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2019-07-16Merge branch 'proc-cmdline' (/proc/<pid>/cmdline fixes)Linus Torvalds1-57/+75
This fixes two problems reported with the cmdline simplification and cleanup last year: - the setproctitle() special cases didn't quite match the original semantics, and it can be noticeable: https://lore.kernel.org/lkml/alpine.LNX.2.21.1904052326230.3249@kich.toxcorp.com/ - it could leak an uninitialized byte from the temporary buffer under the right (wrong) circustances: https://lore.kernel.org/lkml/20190712160913.17727-1-izbyshev@ispras.ru/ It rewrites the logic entirely, splitting it into two separate commits (and two separate functions) for the two different cases ("unedited cmdline" vs "setproctitle() has been used to change the command line"). * proc-cmdline: /proc/<pid>/cmdline: add back the setproctitle() special case /proc/<pid>/cmdline: remove all the special cases
2019-07-16/proc/<pid>/cmdline: add back the setproctitle() special caseLinus Torvalds1-4/+77
This makes the setproctitle() special case very explicit indeed, and handles it with a separate helper function entirely. In the process, it re-instates the original semantics of simply stopping at the first NUL character when the original last NUL character is no longer there. [ The original semantics can still be seen in mm/util.c: get_cmdline() that is limited to a fixed-size buffer ] This makes the logic about when we use the string lengths etc much more obvious, and makes it easier to see what we do and what the two very different cases are. Note that even when we allow walking past the end of the argument array (because the setproctitle() might have overwritten and overflowed the original argv[] strings), we only allow it when it overflows into the environment region if it is immediately adjacent. [ Fixed for missing 'count' checks noted by Alexey Izbyshev ] Link: https://lore.kernel.org/lkml/alpine.LNX.2.21.1904052326230.3249@kich.toxcorp.com/ Fixes: 5ab827189965 ("fs/proc: simplify and clarify get_mm_cmdline() function") Cc: Jakub Jankowski <shasta@toxcorp.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Alexey Izbyshev <izbyshev@ispras.ru> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-16/proc/<pid>/cmdline: remove all the special casesLinus Torvalds1-63/+8
Start off with a clean slate that only reads exactly from arg_start to arg_end, without any oddities. This simplifies the code and in the process removes the case that caused us to potentially leak an uninitialized byte from the temporary kernel buffer. Note that in order to start from scratch with an understandable base, this simplifies things _too_ much, and removes all the legacy logic to handle setproctitle() having changed the argument strings. We'll add back those special cases very differently in the next commit. Link: https://lore.kernel.org/lkml/20190712160913.17727-1-izbyshev@ispras.ru/ Fixes: f5b65348fd77 ("proc: fix missing final NUL in get_mm_cmdline() rewrite") Cc: Alexey Izbyshev <izbyshev@ispras.ru> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12oom: decouple mems_allowed from oom_unkillable_taskShakeel Butt1-2/+1
Commit ef08e3b4981a ("[PATCH] cpusets: confine oom_killer to mem_exclusive cpuset") introduces a heuristic where a potential oom-killer victim is skipped if the intersection of the potential victim and the current (the process triggered the oom) is empty based on the reason that killing such victim most probably will not help the current allocating process. However the commit 7887a3da753e ("[PATCH] oom: cpuset hint") changed the heuristic to just decrease the oom_badness scores of such potential victim based on the reason that the cpuset of such processes might have changed and previously they may have allocated memory on mems where the current allocating process can allocate from. Unintentionally 7887a3da753e ("[PATCH] oom: cpuset hint") introduced a side effect as the oom_badness is also exposed to the user space through /proc/[pid]/oom_score, so, readers with different cpusets can read different oom_score of the same process. Later, commit 6cf86ac6f36b ("oom: filter tasks not sharing the same cpuset") fixed the side effect introduced by 7887a3da753e by moving the cpuset intersection back to only oom-killer context and out of oom_badness. However the combination of ab290adbaf8f ("oom: make oom_unkillable_task() helper function") and 26ebc984913b ("oom: /proc/<pid>/oom_score treat kernel thread honestly") unintentionally brought back the cpuset intersection check into the oom_badness calculation function. Other than doing cpuset/mempolicy intersection from oom_badness, the memcg oom context is also doing cpuset/mempolicy intersection which is quite wrong and is caught by syzcaller with the following report: kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 28426 Comm: syz-executor.5 Not tainted 5.2.0-rc3-next-20190607 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff RSP: 0018:ffff888000127490 EFLAGS: 00010a03 RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000607304 CR3: 000000009237e000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: oom_evaluate_task+0x49/0x520 mm/oom_kill.c:321 mem_cgroup_scan_tasks+0xcc/0x180 mm/memcontrol.c:1169 select_bad_process mm/oom_kill.c:374 [inline] out_of_memory mm/oom_kill.c:1088 [inline] out_of_memory+0x6b2/0x1280 mm/oom_kill.c:1035 mem_cgroup_out_of_memory+0x1ca/0x230 mm/memcontrol.c:1573 mem_cgroup_oom mm/memcontrol.c:1905 [inline] try_charge+0xfbe/0x1480 mm/memcontrol.c:2468 mem_cgroup_try_charge+0x24d/0x5e0 mm/memcontrol.c:6073 mem_cgroup_try_charge_delay+0x1f/0xa0 mm/memcontrol.c:6088 do_huge_pmd_wp_page_fallback+0x24f/0x1680 mm/huge_memory.c:1201 do_huge_pmd_wp_page+0x7fc/0x2160 mm/huge_memory.c:1359 wp_huge_pmd mm/memory.c:3793 [inline] __handle_mm_fault+0x164c/0x3eb0 mm/memory.c:4006 handle_mm_fault+0x3b7/0xa90 mm/memory.c:4053 do_user_addr_fault arch/x86/mm/fault.c:1455 [inline] __do_page_fault+0x5ef/0xda0 arch/x86/mm/fault.c:1521 do_page_fault+0x71/0x57d arch/x86/mm/fault.c:1552 page_fault+0x1e/0x30 arch/x86/entry/entry_64.S:1156 RIP: 0033:0x400590 Code: 06 e9 49 01 00 00 48 8b 44 24 10 48 0b 44 24 28 75 1f 48 8b 14 24 48 8b 7c 24 20 be 04 00 00 00 e8 f5 56 00 00 48 8b 74 24 08 <89> 06 e9 1e 01 00 00 48 8b 44 24 08 48 8b 14 24 be 04 00 00 00 8b RSP: 002b:00007fff7bc49780 EFLAGS: 00010206 RAX: 0000000000000001 RBX: 0000000000760000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000000002000cffc RDI: 0000000000000001 RBP: fffffffffffffffe R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000760008 R13: 00000000004c55f2 R14: 0000000000000000 R15: 00007fff7bc499b0 Modules linked in: ---[ end trace a65689219582ffff ]--- RIP: 0010:__read_once_size include/linux/compiler.h:194 [inline] RIP: 0010:has_intersects_mems_allowed mm/oom_kill.c:84 [inline] RIP: 0010:oom_unkillable_task mm/oom_kill.c:168 [inline] RIP: 0010:oom_unkillable_task+0x180/0x400 mm/oom_kill.c:155 Code: c1 ea 03 80 3c 02 00 0f 85 80 02 00 00 4c 8b a3 10 07 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8d 74 24 10 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 67 02 00 00 49 8b 44 24 10 4c 8d a0 68 fa ff ff RSP: 0018:ffff888000127490 EFLAGS: 00010a03 RAX: dffffc0000000000 RBX: ffff8880a4cd5438 RCX: ffffffff818dae9c RDX: 100000000c3cc602 RSI: ffffffff818dac8d RDI: 0000000000000001 RBP: ffff8880001274d0 R08: ffff888000086180 R09: ffffed1015d26be0 R10: ffffed1015d26bdf R11: ffff8880ae935efb R12: 8000000061e63007 R13: 0000000000000000 R14: 8000000061e63017 R15: 1ffff11000024ea6 FS: 00005555561f5940(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2f823000 CR3: 000000009237e000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 The fix is to decouple the cpuset/mempolicy intersection check from oom_unkillable_task() and make sure cpuset/mempolicy intersection check is only done in the global oom context. [shakeelb@google.com: change function name and update comment] Link: http://lkml.kernel.org/r/20190628152421.198994-3-shakeelb@google.com Link: http://lkml.kernel.org/r/20190624212631.87212-3-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Reported-by: syzbot+d0fc9d3c166bc5e4a94b@syzkaller.appspotmail.com Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Paul Jackson <pj@sgi.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12mm, oom: remove redundant task_in_mem_cgroup() checkShakeel Butt1-1/+1
oom_unkillable_task() can be called from three different contexts i.e. global OOM, memcg OOM and oom_score procfs interface. At the moment oom_unkillable_task() does a task_in_mem_cgroup() check on the given process. Since there is no reason to perform task_in_mem_cgroup() check for global OOM and oom_score procfs interface, those contexts provide NULL memcg and skips the task_in_mem_cgroup() check. However for memcg OOM context, the oom_unkillable_task() is always called from mem_cgroup_scan_tasks() and thus task_in_mem_cgroup() check becomes redundant and effectively dead code. So, just remove the task_in_mem_cgroup() check altogether. Link: http://lkml.kernel.org/r/20190624212631.87212-2-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Paul Jackson <pj@sgi.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-12proc: use down_read_killable mmap_sem for /proc/pid/map_filesKonstantin Khlebnikov1-6/+22
Do not remain stuck forever if something goes wrong. Using a killable lock permits cleanup of stuck tasks and simplifies investigation. It seems ->d_revalidate() could return any error (except ECHILD) to abort validation and pass error as result of lookup sequence. [akpm@linux-foundation.org: fix proc_map_files_lookup() return value, per Andrei] Link: http://lkml.kernel.org/r/156007493995.3335.9595044802115356911.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Roman Gushchin <guro@fb.com> Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com> Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-09Merge branch 'x86-core-for-linus' of ↵Linus Torvalds1-0/+6
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 AVX512 status update from Ingo Molnar: "This adds a new ABI that the main scheduler probably doesn't want to deal with but HPC job schedulers might want to use: the AVX512_elapsed_ms field in the new /proc/<pid>/arch_status task status file, which allows the user-space job scheduler to cluster such tasks, to avoid turbo frequency drops" * 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation/filesystems/proc.txt: Add arch_status file x86/process: Add AVX-512 usage elapsed time to /proc/pid/arch_status proc: Add /proc/<pid>/arch_status
2019-06-27proc: remove useless d_is_dir() checkChristian Brauner1-2/+1
Remove the d_is_dir() check from tgid_pidfd_to_pid(). It is pointless since you should never get &proc_tgid_base_operations for f_op on a non-directory. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Christian Brauner <christian@brauner.io>
2019-06-12proc: Add /proc/<pid>/arch_statusAubrey Li1-0/+6
Exposing architecture specific per process information is useful for various reasons. An example is the AVX512 usage on x86 which is important for task placement for power/performance optimizations. Adding this information to the existing /prcc/pid/status file would be the obvious choise, but it has been agreed on that a explicit arch_status file is better in separating the generic and architecture specific information. [ tglx: Massage changelog ] Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andrew Morton <akpm@linux-foundation.org> Cc: peterz@infradead.org Cc: hpa@zytor.com Cc: ak@linux.intel.com Cc: tim.c.chen@linux.intel.com Cc: dave.hansen@intel.com Cc: arjan@linux.intel.com Cc: adobriyan@gmail.com Cc: aubrey.li@intel.com Cc: linux-api@vger.kernel.org Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Linux API <linux-api@vger.kernel.org> Link: https://lkml.kernel.org/r/20190606012236.9391-1-aubrey.li@linux.intel.com
2019-05-15kernel/latencytop.c: rename clear_all_latency_tracing to ↵Lin Feng1-1/+1
clear_tsk_latency_tracing The name clear_all_latency_tracing is misleading, in fact which only clear per task's latency_record[], and we do have another function named clear_global_latency_tracing which clear the global latency_record[] buffer. Link: http://lkml.kernel.org/r/20190226114602.16902-1-linf@wangsu.com Signed-off-by: Lin Feng <linf@wangsu.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-08Merge tag 'selinux-pr-20190507' of ↵Linus Torvalds1-0/+5
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux Pull selinux updates from Paul Moore: "We've got a few SELinux patches for the v5.2 merge window, the highlights are below: - Add LSM hooks, and the SELinux implementation, for proper labeling of kernfs. While we are only including the SELinux implementation here, the rest of the LSM folks have given the hooks a thumbs-up. - Update the SELinux mdp (Make Dummy Policy) script to actually work on a modern system. - Disallow userspace to change the LSM credentials via /proc/self/attr when the task's credentials are already overridden. The change was made in procfs because all the LSM folks agreed this was the Right Thing To Do and duplicating it across each LSM was going to be annoying" * tag 'selinux-pr-20190507' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux: proc: prevent changes to overridden credentials selinux: Check address length before reading address family kernfs: fix xattr name handling in LSM helpers MAINTAINERS: update SELinux file patterns selinux: avoid uninitialized variable warning selinux: remove useless assignments LSM: lsm_hooks.h - fix missing colon in docstring selinux: Make selinux_kernfs_init_security static kernfs: initialize security of newly created nodes selinux: implement the kernfs_init_security hook LSM: add new hook for kernfs node initialization kernfs: use simple_xattrs for security attributes selinux: try security xattr after genfs for kernfs filesystems kernfs: do not alloc iattrs in kernfs_xattr_get kernfs: clean up struct kernfs_iattrs scripts/selinux: fix build selinux: use kernel linux/socket.h for genheaders and mdp scripts/selinux: modernize mdp
2019-04-29proc: prevent changes to overridden credentialsPaul Moore1-0/+5
Prevent userspace from changing the the /proc/PID/attr values if the task's credentials are currently overriden. This not only makes sense conceptually, it also prevents some really bizarre error cases caused when trying to commit credentials to a task with overridden credentials. Cc: <stable@vger.kernel.org> Reported-by: "chengjian (D)" <cj.chengjian@huawei.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Acked-by: John Johansen <john.johansen@canonical.com> Acked-by: James Morris <james.morris@microsoft.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com>
2019-04-29proc: Simplify task stack retrievalThomas Gleixner1-9/+5
Replace the indirection through struct stack_trace with an invocation of the storage array based interface. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094801.589304463@linutronix.de
2019-04-14latency_top: Remove the ULONG_MAX stack trace hackeryThomas Gleixner1-2/+1
No architecture terminates the stack trace with ULONG_MAX anymore. The consumer terminates on the first zero entry or at the number of entries, so no functional change. Remove the cruft. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Link: https://lkml.kernel.org/r/20190410103644.853527514@linutronix.de
2019-04-04ptrace: Remove maxargs from task_current_syscall()Steven Rostedt (Red Hat)1-8/+9
task_current_syscall() has a single user that passes in 6 for maxargs, which is the maximum arguments that can be used to get system calls from syscall_get_arguments(). Instead of passing in a number of arguments to grab, just get 6 arguments. The args argument even specifies that it's an array of 6 items. This will also allow changing syscall_get_arguments() to not get a variable number of arguments, but always grab 6. Linus also suggested not passing in a bunch of arguments to task_current_syscall() but to instead pass in a pointer to a structure, and just fill the structure. struct seccomp_data has almost all the parameters that is needed except for the stack pointer (sp). As seccomp_data is part of uapi, and I'm afraid to change it, a new structure was created "syscall_info", which includes seccomp_data and adds the "sp" field. Link: http://lkml.kernel.org/r/20161107213233.466776454@goodmis.org Cc: Andy Lutomirski <luto@kernel.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2019-03-16Merge tag 'pidfd-v5.1-rc1' of ↵Linus Torvalds1-0/+9
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull pidfd system call from Christian Brauner: "This introduces the ability to use file descriptors from /proc/<pid>/ as stable handles on struct pid. Even if a pid is recycled the handle will not change. For a start these fds can be used to send signals to the processes they refer to. With the ability to use /proc/<pid> fds as stable handles on struct pid we can fix a long-standing issue where after a process has exited its pid can be reused by another process. If a caller sends a signal to a reused pid it will end up signaling the wrong process. With this patchset we enable a variety of use cases. One obvious example is that we can now safely delegate an important part of process management - sending signals - to processes other than the parent of a given process by sending file descriptors around via scm rights and not fearing that the given process will have been recycled in the meantime. It also allows for easy testing whether a given process is still alive or not by sending signal 0 to a pidfd which is quite handy. There has been some interest in this feature e.g. from systems management (systemd, glibc) and container managers. I have requested and gotten comments from glibc to make sure that this syscall is suitable for their needs as well. In the future I expect it to take on most other pid-based signal syscalls. But such features are left for the future once they are needed. This has been sitting in linux-next for quite a while and has not caused any issues. It comes with selftests which verify basic functionality and also test that a recycled pid cannot be signaled via a pidfd. Jon has written about a prior version of this patchset. It should cover the basic functionality since not a lot has changed since then: https://lwn.net/Articles/773459/ The commit message for the syscall itself is extensively documenting the syscall, including it's functionality and extensibility" * tag 'pidfd-v5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: selftests: add tests for pidfd_send_signal() signal: add pidfd_send_signal() syscall
2019-03-12proc: commit to genradixKent Overstreet1-28/+15
The new generic radix trees have a simpler API and implementation, and no limitations on number of elements, so all flex_array users are being converted Link: http://lkml.kernel.org/r/20181217131929.11727-6-kent.overstreet@gmail.com Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Eric Paris <eparis@parisplace.org> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Paul Moore <paul@paul-moore.com> Cc: Pravin B Shelar <pshelar@ovn.org> Cc: Shaohua Li <shli@kernel.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-12proc: calculate end pointer for /proc/*/* lookup at compile timeAlexey Dobriyan1-9/+10
Compilers like to transform loops like for (i = 0; i < n; i++) { [use p[i]] } into for (p = p0; p < end; p++) { ... } Do it by hand, so that it results in overall simpler loop and smaller code. Space savings: $ ./scripts/bloat-o-meter ../vmlinux-001 ../obj/vmlinux add/remove: 0/0 grow/shrink: 2/1 up/down: 4/-9 (-5) Function old new delta proc_tid_base_lookup 17 19 +2 proc_tgid_base_lookup 17 19 +2 proc_pident_lookup 179 170 -9 The same could be done to proc_pident_readdir(), but the code becomes bigger for some reason. [sfr@canb.auug.org.au: merge fix for proc_pident_lookup() API change] Link: http://lkml.kernel.org/r/20190131160135.4a8ae70b@canb.auug.org.au Link: http://lkml.kernel.org/r/20190114200422.GB9680@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: James Morris <jmorris@namei.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07Merge tag 'audit-pr-20190305' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit Pull audit updates from Paul Moore: "A lucky 13 audit patches for v5.1. Despite the rather large diffstat, most of the changes are from two bug fix patches that move code from one Kconfig option to another. Beyond that bit of churn, the remaining changes are largely cleanups and bug-fixes as we slowly march towards container auditing. It isn't all boring though, we do have a couple of new things: file capabilities v3 support, and expanded support for filtering on filesystems to solve problems with remote filesystems. All changes pass the audit-testsuite. Please merge for v5.1" * tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit: audit: mark expected switch fall-through audit: hide auditsc_get_stamp and audit_serial prototypes audit: join tty records to their syscall audit: remove audit_context when CONFIG_ AUDIT and not AUDITSYSCALL audit: remove unused actx param from audit_rule_match audit: ignore fcaps on umount audit: clean up AUDITSYSCALL prototypes and stubs audit: more filter PATH records keyed on filesystem magic audit: add support for fcaps v3 audit: move loginuid and sessionid from CONFIG_AUDITSYSCALL to CONFIG_AUDIT audit: add syscall information to CONFIG_CHANGE records audit: hand taken context to audit_kill_trees for syscall logging audit: give a clue what CONFIG_CHANGE op was involved
2019-03-07Merge branch 'next-general' of ↵Linus Torvalds1-9/+55
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: - Extend LSM stacking to allow sharing of cred, file, ipc, inode, and task blobs. This paves the way for more full-featured LSMs to be merged, and is specifically aimed at LandLock and SARA LSMs. This work is from Casey and Kees. - There's a new LSM from Micah Morton: "SafeSetID gates the setid family of syscalls to restrict UID/GID transitions from a given UID/GID to only those approved by a system-wide whitelist." This feature is currently shipping in ChromeOS. * 'next-general' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (62 commits) keys: fix missing __user in KEYCTL_PKEY_QUERY LSM: Update list of SECURITYFS users in Kconfig LSM: Ignore "security=" when "lsm=" is specified LSM: Update function documentation for cap_capable security: mark expected switch fall-throughs and add a missing break tomoyo: Bump version. LSM: fix return value check in safesetid_init_securityfs() LSM: SafeSetID: add selftest LSM: SafeSetID: remove unused include LSM: SafeSetID: 'depend' on CONFIG_SECURITY LSM: Add 'name' field for SafeSetID in DEFINE_LSM LSM: add SafeSetID module that gates setid calls LSM: add SafeSetID module that gates setid calls tomoyo: Allow multiple use_group lines. tomoyo: Coding style fix. tomoyo: Swicth from cred->security to task_struct->security. security: keys: annotate implicit fall throughs security: keys: annotate implicit fall throughs security: keys: annotate implicit fall through capabilities:: annotate implicit fall through ...
2019-03-06proc: use seq_puts() everywhereAlexey Dobriyan1-1/+1
seq_printf() without format specifiers == faster seq_puts() Link: http://lkml.kernel.org/r/20190114200545.GC9680@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-06proc: remove unused argument in proc_pid_lookup()Zhikang Zhang1-1/+1
[adobriyan@gmail.com: delete "extern" from prototype] Link: http://lkml.kernel.org/r/20190114195635.GA9372@avx2 Signed-off-by: Zhikang Zhang <zhangzhikang1@huawei.com> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05signal: add pidfd_send_signal() syscallChristian Brauner1-0/+9
The kill() syscall operates on process identifiers (pid). After a process has exited its pid can be reused by another process. If a caller sends a signal to a reused pid it will end up signaling the wrong process. This issue has often surfaced and there has been a push to address this problem [1]. This patch uses file descriptors (fd) from proc/<pid> as stable handles on struct pid. Even if a pid is recycled the handle will not change. The fd can be used to send signals to the process it refers to. Thus, the new syscall pidfd_send_signal() is introduced to solve this problem. Instead of pids it operates on process fds (pidfd). /* prototype and argument /* long pidfd_send_signal(int pidfd, int sig, siginfo_t *info, unsigned int flags); /* syscall number 424 */ The syscall number was chosen to be 424 to align with Arnd's rework in his y2038 to minimize merge conflicts (cf. [25]). In addition to the pidfd and signal argument it takes an additional siginfo_t and flags argument. If the siginfo_t argument is NULL then pidfd_send_signal() is equivalent to kill(<positive-pid>, <signal>). If it is not NULL pidfd_send_signal() is equivalent to rt_sigqueueinfo(). The flags argument is added to allow for future extensions of this syscall. It currently needs to be passed as 0. Failing to do so will cause EINVAL. /* pidfd_send_signal() replaces multiple pid-based syscalls */ The pidfd_send_signal() syscall currently takes on the job of rt_sigqueueinfo(2) and parts of the functionality of kill(2), Namely, when a positive pid is passed to kill(2). It will however be possible to also replace tgkill(2) and rt_tgsigqueueinfo(2) if this syscall is extended. /* sending signals to threads (tid) and process groups (pgid) */ Specifically, the pidfd_send_signal() syscall does currently not operate on process groups or threads. This is left for future extensions. In order to extend the syscall to allow sending signal to threads and process groups appropriately named flags (e.g. PIDFD_TYPE_PGID, and PIDFD_TYPE_TID) should be added. This implies that the flags argument will determine what is signaled and not the file descriptor itself. Put in other words, grouping in this api is a property of the flags argument not a property of the file descriptor (cf. [13]). Clarification for this has been requested by Eric (cf. [19]). When appropriate extensions through the flags argument are added then pidfd_send_signal() can additionally replace the part of kill(2) which operates on process groups as well as the tgkill(2) and rt_tgsigqueueinfo(2) syscalls. How such an extension could be implemented has been very roughly sketched in [14], [15], and [16]. However, this should not be taken as a commitment to a particular implementation. There might be better ways to do it. Right now this is intentionally left out to keep this patchset as simple as possible (cf. [4]). /* naming */ The syscall had various names throughout iterations of this patchset: - procfd_signal() - procfd_send_signal() - taskfd_send_signal() In the last round of reviews it was pointed out that given that if the flags argument decides the scope of the signal instead of different types of fds it might make sense to either settle for "procfd_" or "pidfd_" as prefix. The community was willing to accept either (cf. [17] and [18]). Given that one developer expressed strong preference for the "pidfd_" prefix (cf. [13]) and with other developers less opinionated about the name we should settle for "pidfd_" to avoid further bikeshedding. The "_send_signal" suffix was chosen to reflect the fact that the syscall takes on the job of multiple syscalls. It is therefore intentional that the name is not reminiscent of neither kill(2) nor rt_sigqueueinfo(2). Not the fomer because it might imply that pidfd_send_signal() is a replacement for kill(2), and not the latter because it is a hassle to remember the correct spelling - especially for non-native speakers - and because it is not descriptive enough of what the syscall actually does. The name "pidfd_send_signal" makes it very clear that its job is to send signals. /* zombies */ Zombies can be signaled just as any other process. No special error will be reported since a zombie state is an unreliable state (cf. [3]). However, this can be added as an extension through the @flags argument if the need ever arises. /* cross-namespace signals */ The patch currently enforces that the signaler and signalee either are in the same pid namespace or that the signaler's pid namespace is an ancestor of the signalee's pid namespace. This is done for the sake of simplicity and because it is unclear to what values certain members of struct siginfo_t would need to be set to (cf. [5], [6]). /* compat syscalls */ It became clear that we would like to avoid adding compat syscalls (cf. [7]). The compat syscall handling is now done in kernel/signal.c itself by adding __copy_siginfo_from_user_generic() which lets us avoid compat syscalls (cf. [8]). It should be noted that the addition of __copy_siginfo_from_user_any() is caused by a bug in the original implementation of rt_sigqueueinfo(2) (cf. 12). With upcoming rework for syscall handling things might improve significantly (cf. [11]) and __copy_siginfo_from_user_any() will not gain any additional callers. /* testing */ This patch was tested on x64 and x86. /* userspace usage */ An asciinema recording for the basic functionality can be found under [9]. With this patch a process can be killed via: #define _GNU_SOURCE #include <errno.h> #include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/stat.h> #include <sys/syscall.h> #include <sys/types.h> #include <unistd.h> static inline int do_pidfd_send_signal(int pidfd, int sig, siginfo_t *info, unsigned int flags) { #ifdef __NR_pidfd_send_signal return syscall(__NR_pidfd_send_signal, pidfd, sig, info, flags); #else return -ENOSYS; #endif } int main(int argc, char *argv[]) { int fd, ret, saved_errno, sig; if (argc < 3) exit(EXIT_FAILURE); fd = open(argv[1], O_DIRECTORY | O_CLOEXEC); if (fd < 0) { printf("%s - Failed to open \"%s\"\n", strerror(errno), argv[1]); exit(EXIT_FAILURE); } sig = atoi(argv[2]); printf("Sending signal %d to process %s\n", sig, argv[1]); ret = do_pidfd_send_signal(fd, sig, NULL, 0); saved_errno = errno; close(fd); errno = saved_errno; if (ret < 0) { printf("%s - Failed to send signal %d to process %s\n", strerror(errno), sig, argv[1]); exit(EXIT_FAILURE); } exit(EXIT_SUCCESS); } /* Q&A * Given that it seems the same questions get asked again by people who are * late to the party it makes sense to add a Q&A section to the commit * message so it's hopefully easier to avoid duplicate threads. * * For the sake of progress please consider these arguments settled unless * there is a new point that desperately needs to be addressed. Please make * sure to check the links to the threads in this commit message whether * this has not already been covered. */ Q-01: (Florian Weimer [20], Andrew Morton [21]) What happens when the target process has exited? A-01: Sending the signal will fail with ESRCH (cf. [22]). Q-02: (Andrew Morton [21]) Is the task_struct pinned by the fd? A-02: No. A reference to struct pid is kept. struct pid - as far as I understand - was created exactly for the reason to not require to pin struct task_struct (cf. [22]). Q-03: (Andrew Morton [21]) Does the entire procfs directory remain visible? Just one entry within it? A-03: The same thing that happens right now when you hold a file descriptor to /proc/<pid> open (cf. [22]). Q-04: (Andrew Morton [21]) Does the pid remain reserved? A-04: No. This patchset guarantees a stable handle not that pids are not recycled (cf. [22]). Q-05: (Andrew Morton [21]) Do attempts to signal that fd return errors? A-05: See {Q,A}-01. Q-06: (Andrew Morton [22]) Is there a cleaner way of obtaining the fd? Another syscall perhaps. A-06: Userspace can already trivially retrieve file descriptors from procfs so this is something that we will need to support anyway. Hence, there's no immediate need to add another syscalls just to make pidfd_send_signal() not dependent on the presence of procfs. However, adding a syscalls to get such file descriptors is planned for a future patchset (cf. [22]). Q-07: (Andrew Morton [21] and others) This fd-for-a-process sounds like a handy thing and people may well think up other uses for it in the future, probably unrelated to signals. Are the code and the interface designed to permit such future applications? A-07: Yes (cf. [22]). Q-08: (Andrew Morton [21] and others) Now I think about it, why a new syscall? This thing is looking rather like an ioctl? A-08: This has been extensively discussed. It was agreed that a syscall is preferred for a variety or reasons. Here are just a few taken from prior threads. Syscalls are safer than ioctl()s especially when signaling to fds. Processes are a core kernel concept so a syscall seems more appropriate. The layout of the syscall with its four arguments would require the addition of a custom struct for the ioctl() thereby causing at least the same amount or even more complexity for userspace than a simple syscall. The new syscall will replace multiple other pid-based syscalls (see description above). The file-descriptors-for-processes concept introduced with this syscall will be extended with other syscalls in the future. See also [22], [23] and various other threads already linked in here. Q-09: (Florian Weimer [24]) What happens if you use the new interface with an O_PATH descriptor? A-09: pidfds opened as O_PATH fds cannot be used to send signals to a process (cf. [2]). Signaling processes through pidfds is the equivalent of writing to a file. Thus, this is not an operation that operates "purely at the file descriptor level" as required by the open(2) manpage. See also [4]. /* References */ [1]: https://lore.kernel.org/lkml/20181029221037.87724-1-dancol@google.com/ [2]: https://lore.kernel.org/lkml/874lbtjvtd.fsf@oldenburg2.str.redhat.com/ [3]: https://lore.kernel.org/lkml/20181204132604.aspfupwjgjx6fhva@brauner.io/ [4]: https://lore.kernel.org/lkml/20181203180224.fkvw4kajtbvru2ku@brauner.io/ [5]: https://lore.kernel.org/lkml/20181121213946.GA10795@mail.hallyn.com/ [6]: https://lore.kernel.org/lkml/20181120103111.etlqp7zop34v6nv4@brauner.io/ [7]: https://lore.kernel.org/lkml/36323361-90BD-41AF-AB5B-EE0D7BA02C21@amacapital.net/ [8]: https://lore.kernel.org/lkml/87tvjxp8pc.fsf@xmission.com/ [9]: https://asciinema.org/a/IQjuCHew6bnq1cr78yuMv16cy [11]: https://lore.kernel.org/lkml/F53D6D38-3521-4C20-9034-5AF447DF62FF@amacapital.net/ [12]: https://lore.kernel.org/lkml/87zhtjn8ck.fsf@xmission.com/ [13]: https://lore.kernel.org/lkml/871s6u9z6u.fsf@xmission.com/ [14]: https://lore.kernel.org/lkml/20181206231742.xxi4ghn24z4h2qki@brauner.io/ [15]: https://lore.kernel.org/lkml/20181207003124.GA11160@mail.hallyn.com/ [16]: https://lore.kernel.org/lkml/20181207015423.4miorx43l3qhppfz@brauner.io/ [17]: https://lore.kernel.org/lkml/CAGXu5jL8PciZAXvOvCeCU3wKUEB_dU-O3q0tDw4uB_ojMvDEew@mail.gmail.com/ [18]: https://lore.kernel.org/lkml/20181206222746.GB9224@mail.hallyn.com/ [19]: https://lore.kernel.org/lkml/20181208054059.19813-1-christian@brauner.io/ [20]: https://lore.kernel.org/lkml/8736rebl9s.fsf@oldenburg.str.redhat.com/ [21]: https://lore.kernel.org/lkml/20181228152012.dbf0508c2508138efc5f2bbe@linux-foundation.org/ [22]: https://lore.kernel.org/lkml/20181228233725.722tdfgijxcssg76@brauner.io/ [23]: https://lwn.net/Articles/773459/ [24]: https://lore.kernel.org/lkml/8736rebl9s.fsf@oldenburg.str.redhat.com/ [25]: https://lore.kernel.org/lkml/CAK8P3a0ej9NcJM8wXNPbcGUyOUZYX+VLoDFdbenW3s3114oQZw@mail.gmail.com/ Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Jann Horn <jannh@google.com> Cc: Andy Lutomirsky <luto@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Florian Weimer <fweimer@redhat.com> Signed-off-by: Christian Brauner <christian@brauner.io> Reviewed-by: Tycho Andersen <tycho@tycho.ws> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Serge Hallyn <serge@hallyn.com> Acked-by: Aleksa Sarai <cyphar@cyphar.com>
2019-02-21proc, oom: do not report alien mms when setting oom_score_adjMichal Hocko1-4/+0
Tetsuo has reported that creating a thousands of processes sharing MM without SIGHAND (aka alien threads) and setting /proc/<pid>/oom_score_adj will swamp the kernel log and takes ages [1] to finish. This is especially worrisome that all that printing is done under RCU lock and this can potentially trigger RCU stall or softlockup detector. The primary reason for the printk was to catch potential users who might depend on the behavior prior to 44a70adec910 ("mm, oom_adj: make sure processes sharing mm have same view of oom_score_adj") but after more than 2 years without a single report I guess it is safe to simply remove the printk altogether. The next step should be moving oom_score_adj over to the mm struct and remove all the tasks crawling as suggested by [2] [1] http://lkml.kernel.org/r/97fce864-6f75-bca5-14bc-12c9f890e740@i-love.sakura.ne.jp [2] http://lkml.kernel.org/r/20190117155159.GA4087@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20190212102129.26288-1-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: David Rientjes <rientjes@google.com> Cc: Yong-Taek Lee <ytk.lee@samsung.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-25audit: move loginuid and sessionid from CONFIG_AUDITSYSCALL to CONFIG_AUDITRichard Guy Briggs1-3/+3
loginuid and sessionid (and audit_log_session_info) should be part of CONFIG_AUDIT scope and not CONFIG_AUDITSYSCALL since it is used in CONFIG_CHANGE, ANOM_LINK, FEATURE_CHANGE (and INTEGRITY_RULE), none of which are otherwise dependent on AUDITSYSCALL. Please see github issue https://github.com/linux-audit/audit-kernel/issues/104 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: tweaked subject line for better grep'ing] Signed-off-by: Paul Moore <paul@paul-moore.com>
2019-01-09procfs: add smack subdir to attrsCasey Schaufler1-9/+55
Back in 2007 I made what turned out to be a rather serious mistake in the implementation of the Smack security module. The SELinux module used an interface in /proc to manipulate the security context on processes. Rather than use a similar interface, I used the same interface. The AppArmor team did likewise. Now /proc/.../attr/current will tell you the security "context" of the process, but it will be different depending on the security module you're using. This patch provides a subdirectory in /proc/.../attr for Smack. Smack user space can use the "current" file in this subdirectory and never have to worry about getting SELinux attributes by mistake. Programs that use the old interface will continue to work (or fail, as the case may be) as before. The proposed S.A.R.A security module is dependent on the mechanism to create its own attr subdirectory. The original implementation is by Kees Cook. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
2019-01-05fs/proc/base.c: slightly faster /proc/*/limitsAlexey Dobriyan1-2/+4
Header of /proc/*/limits is a fixed string, so print it directly without formatting specifiers. Link: http://lkml.kernel.org/r/20181203164242.GB6904@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-05fs/proc/base.c: use ns_capable instead of capable for timerslack_nsBenjamin Gordon1-3/+9
Access to timerslack_ns is controlled by a process having CAP_SYS_NICE in its effective capability set, but the current check looks in the root namespace instead of the process' user namespace. Since a process is allowed to do other activities controlled by CAP_SYS_NICE inside a namespace, it should also be able to adjust timerslack_ns. Link: http://lkml.kernel.org/r/20181030180012.232896-1-bmgordon@google.com Signed-off-by: Benjamin Gordon <bmgordon@google.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: John Stultz <john.stultz@linaro.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Oren Laadan <orenl@cellrox.com> Cc: Ruchi Kandoi <kandoiruchi@google.com> Cc: Rom Lemarchand <romlem@android.com> Cc: Todd Kjos <tkjos@google.com> Cc: Colin Cross <ccross@android.com> Cc: Nick Kralevich <nnk@google.com> Cc: Dmitry Shmidt <dimitrysh@google.com> Cc: Elliott Hughes <enh@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28mm: convert totalram_pages and totalhigh_pages variables to atomicArun KS1-1/+1
totalram_pages and totalhigh_pages are made static inline function. Main motivation was that managed_page_count_lock handling was complicating things. It was discussed in length here, https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes better to remove the lock and convert variables to atomic, with preventing poteintial store-to-read tearing as a bonus. [akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.org Signed-off-by: Arun KS <arunks@codeaurora.org> Suggested-by: Michal Hocko <mhocko@suse.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-11-01Merge tag 'stackleak-v4.20-rc1' of ↵Linus Torvalds1-0/+18
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull stackleak gcc plugin from Kees Cook: "Please pull this new GCC plugin, stackleak, for v4.20-rc1. This plugin was ported from grsecurity by Alexander Popov. It provides efficient stack content poisoning at syscall exit. This creates a defense against at least two classes of flaws: - Uninitialized stack usage. (We continue to work on improving the compiler to do this in other ways: e.g. unconditional zero init was proposed to GCC and Clang, and more plugin work has started too). - Stack content exposure. By greatly reducing the lifetime of valid stack contents, exposures via either direct read bugs or unknown cache side-channels become much more difficult to exploit. This complements the existing buddy and heap poisoning options, but provides the coverage for stacks. The x86 hooks are included in this series (which have been reviewed by Ingo, Dave Hansen, and Thomas Gleixner). The arm64 hooks have already been merged through the arm64 tree (written by Laura Abbott and reviewed by Mark Rutland and Will Deacon). With VLAs having been removed this release, there is no need for alloca() protection, so it has been removed from the plugin" * tag 'stackleak-v4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: arm64: Drop unneeded stackleak_check_alloca() stackleak: Allow runtime disabling of kernel stack erasing doc: self-protection: Add information about STACKLEAK feature fs/proc: Show STACKLEAK metrics in the /proc file system lkdtm: Add a test for STACKLEAK gcc-plugins: Add STACKLEAK plugin for tracking the kernel stack x86/entry: Add STACKLEAK erasing the kernel stack at the end of syscalls
2018-10-06proc: restrict kernel stack dumps to rootJann Horn1-0/+14
Currently, you can use /proc/self/task/*/stack to cause a stack walk on a task you control while it is running on another CPU. That means that the stack can change under the stack walker. The stack walker does have guards against going completely off the rails and into random kernel memory, but it can interpret random data from your kernel stack as instruction pointers and stack pointers. This can cause exposure of kernel stack contents to userspace. Restrict the ability to inspect kernel stacks of arbitrary tasks to root in order to prevent a local attacker from exploiting racy stack unwinding to leak kernel task stack contents. See the added comment for a longer rationale. There don't seem to be any users of this userspace API that can't gracefully bail out if reading from the file fails. Therefore, I believe that this change is unlikely to break things. In the case that this patch does end up needing a revert, the next-best solution might be to fake a single-entry stack based on wchan. Link: http://lkml.kernel.org/r/20180927153316.200286-1-jannh@google.com Fixes: 2ec220e27f50 ("proc: add /proc/*/stack") Signed-off-by: Jann Horn <jannh@google.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ken Chen <kenchen@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-04fs/proc: Show STACKLEAK metrics in the /proc file systemAlexander Popov1-0/+18
Introduce CONFIG_STACKLEAK_METRICS providing STACKLEAK information about tasks via the /proc file system. In particular, /proc/<pid>/stack_depth shows the maximum kernel stack consumption for the current and previous syscalls. Although this information is not precise, it can be useful for estimating the STACKLEAK performance impact for your workloads. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Alexander Popov <alex.popov@linux.com> Tested-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2018-08-22proc: use macro in /proc/latency hookAlexey Dobriyan1-1/+1
->latency_record is defined as struct latency_record[LT_SAVECOUNT]; so use the same macro whie iterating. Link: http://lkml.kernel.org/r/20180627200534.GA18434@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22proc: save 2 atomic ops on write to "/proc/*/attr/*"Alexey Dobriyan1-19/+19
Code checks if write is done by current to its own attributes. For that get/put pair is unnecessary as it can be done under RCU. Note: rcu_read_unlock() can be done even earlier since pointer to a task is not dereferenced. It depends if /proc code should look scary or not: rcu_read_lock(); task = pid_task(...); rcu_read_unlock(); if (!task) return -ESRCH; if (task != current) return -EACCESS: P.S.: rename "length" variable. Code like this length = -EINVAL; should not exist. Link: http://lkml.kernel.org/r/20180627200218.GF18113@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22proc: put task earlier in /proc/*/fail-nthAlexey Dobriyan1-3/+1
Link: http://lkml.kernel.org/r/20180627195427.GE18113@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-22mm: /proc/pid/*maps remove is_pid and related wrappersVlastimil Babka1-3/+3
Patch series "cleanups and refactor of /proc/pid/smaps*". The recent regression in /proc/pid/smaps made me look more into the code. Especially the issues with smaps_rollup reported in [1] as explained in Patch 4, which fixes them by refactoring the code. Patches 2 and 3 are preparations for that. Patch 1 is me realizing that there's a lot of boilerplate left from times where we tried (unsuccessfuly) to mark thread stacks in the output. Originally I had also plans to rework the translation from /proc/pid/*maps* file offsets to the internal structures. Now the offset means "vma number", which is not really stable (vma's can come and go between read() calls) and there's an extra caching of last vma's address. My idea was that offsets would be interpreted directly as addresses, which would also allow meaningful seeks (see the ugly seek_to_smaps_entry() in tools/testing/selftests/vm/mlock2.h). However loff_t is (signed) long long so that might be insufficient somewhere for the unsigned long addresses. So the result is fixed issues with skewed /proc/pid/smaps_rollup results, simpler smaps code, and a lot of unused code removed. [1] https://marc.info/?l=linux-mm&m=151927723128134&w=2 This patch (of 4): Commit b76437579d13 ("procfs: mark thread stack correctly in proc/<pid>/maps") introduced differences between /proc/PID/maps and /proc/PID/task/TID/maps to mark thread stacks properly, and this was also done for smaps and numa_maps. However it didn't work properly and was ultimately removed by commit b18cb64ead40 ("fs/proc: Stop trying to report thread stacks"). Now the is_pid parameter for the related show_*() functions is unused and we can remove it together with wrapper functions and ops structures that differ for PID and TID cases only in this parameter. Link: http://lkml.kernel.org/r/20180723111933.15443-2-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Daniel Colascione <dancol@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-20proc: fix missing final NUL in get_mm_cmdline() rewriteLinus Torvalds1-5/+23
The rewrite of the cmdline fetching missed the fact that we used to also return the final terminating NUL character of the last argument. I hadn't noticed, and none of the tools I tested cared, but something obviously must care, because Michal Kubecek noticed the change in behavior. Tweak the "find the end" logic to actually include the NUL character, and once past the eend of argv, always start the strnlen() at the expected (original) argument end. This whole "allow people to rewrite their arguments in place" is a nasty hack and requires that odd slop handling at the end of the argv array, but it's our traditional model, so we continue to support it. Repored-and-bisected-by: Michal Kubecek <mkubecek@suse.cz> Reviewed-and-tested-by: Michal Kubecek <mkubecek@suse.cz> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-15proc: skip branch in /proc/*/* lookupAlexey Dobriyan1-6/+3
Code is structured like this: for ( ... p < last; p++) { if (memcmp == 0) break; } if (p >= last) ERROR OK gcc doesn't see that if if lookup succeeds than post loop branch will never be taken and skip it. [akpm@linux-foundation.org: proc_pident_instantiate() no longer takes an inode*] Link: http://lkml.kernel.org/r/20180423213954.GD9043@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-13treewide: kmalloc() -> kmalloc_array()Kees Cook1-1/+2
The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-10Merge branch 'proc-cmdline'Linus Torvalds1-112/+99
Merge proc_cmdline simplifications. This re-writes the get_mm_cmdline() logic to be rather simpler than it used to be, and makes the semantics for "cmdline goes past the end of the original area" more natural. You _can_ use prctl(PR_SET_MM) to just point your command line somewhere else entirely, but the traditional model is to just edit things in place and that still needs to continue to work. At least this way the code makes some sense. * proc-cmdline: fs/proc: simplify and clarify get_mm_cmdline() function fs/proc: re-factor proc_pid_cmdline_read() a bit
2018-06-08Merge branch 'work.lookup' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull proc_fill_cache regression fix from Al Viro: "Regression fix for proc_fill_cache() braino introduced when switching instantiate() callback to d_splice_alias()" * 'work.lookup' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fix proc_fill_cache() in case of d_alloc_parallel() failure
2018-06-08fix proc_fill_cache() in case of d_alloc_parallel() failureAl Viro1-3/+3
If d_alloc_parallel() returns ERR_PTR(...), we don't want to dput() that. Small reorganization allows to have all error-in-lookup cases rejoin the main codepath after dput(child), avoiding the entire problem. Spotted-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Fixes: 0168b9e38c42 "procfs: switch instantiate_t to d_splice_alias()" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-06-08proc: use "unsigned int" for /proc/*/stackAlexey Dobriyan1-1/+2
struct stack_trace::nr_entries is defined as "unsigned int" (YAY!) so the iterator should be unsigned as well. It saves 1 byte of code or something like that. Link: http://lkml.kernel.org/r/20180423215248.GG9043@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08proc: use "unsigned int" in proc_fill_cache()Alexey Dobriyan1-3/+3
All those lengths are unsigned as they should be. Link: http://lkml.kernel.org/r/20180423213751.GC9043@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08proc: smaller RCU section in ->getattr()Alexey Dobriyan1-1/+1
struct kstat is thread local. Link: http://lkml.kernel.org/r/20180423213626.GB9043@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08proc: deduplicate /proc/*/cmdline implementationAlexey Dobriyan1-33/+20
Code can be sonsolidated if a dummy region of 0 length is used in normal case of \0-separated command line: 1) [arg_start, arg_end) + [dummy len=0] 2) [arg_start, arg_end) + [env_start, env_end) Link: http://lkml.kernel.org/r/20180221193335.GB28678@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08proc: simpler iterations for /proc/*/cmdlineAlexey Dobriyan1-19/+14
"rv" variable is used both as a counter of bytes transferred and an error value holder but it can be reduced solely to error values if original start of userspace buffer is stashed and used at the very end. [akpm@linux-foundation.org: simplify cleanup code] Link: http://lkml.kernel.org/r/20180221193009.GA28678@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08proc: somewhat simpler code for /proc/*/cmdlineAlexey Dobriyan1-15/+9
"final" variable is OK but we can get away with less lines. Link: http://lkml.kernel.org/r/20180221192751.GC28548@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08proc: more "unsigned int" in /proc/*/cmdlineAlexey Dobriyan1-17/+12
access_remote_vm() doesn't return negative errors, it returns number of bytes read/written (0 if error occurs). This allows to delete some comparisons which never trigger. Reuse "nr_read" variable while I'm at it. Link: http://lkml.kernel.org/r/20180221192605.GB28548@avx2 Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-08mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_structYang Shi1-4/+4
mmap_sem is on the hot path of kernel, and it very contended, but it is abused too. It is used to protect arg_start|end and evn_start|end when reading /proc/$PID/cmdline and /proc/$PID/environ, but it doesn't make sense since those proc files just expect to read 4 values atomically and not related to VM, they could be set to arbitrary values by C/R. And, the mmap_sem contention may cause unexpected issue like below: INFO: task ps:14018 blocked for more than 120 seconds. Tainted: G E 4.9.79-009.ali3000.alios7.x86_64 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ps D 0 14018 1 0x00000004 Call Trace: schedule+0x36/0x80 rwsem_down_read_failed+0xf0/0x150 call_rwsem_down_read_failed+0x18/0x30 down_read+0x20/0x40 proc_pid_cmdline_read+0xd9/0x4e0 __vfs_read+0x37/0x150 vfs_read+0x96/0x130 SyS_read+0x55/0xc0 entry_SYSCALL_64_fastpath+0x1a/0xc5 Both Alexey Dobriyan and Michal Hocko suggested to use dedicated lock for them to mitigate the abuse of mmap_sem. So, introduce a new spinlock in mm_struct to protect the concurrent access to arg_start|end, env_start|end and others, as well as replace write map_sem to read to protect the race condition between prctl and sys_brk which might break check_data_rlimit(), and makes prctl more friendly to other VM operations. This patch just eliminates the abuse of mmap_sem, but it can't resolve the above hung task warning completely since the later access_remote_vm() call needs acquire mmap_sem. The mmap_sem scalability issue will be solved in the future. [yang.shi@linux.alibaba.com: add comment about mmap_sem and arg_lock] Link: http://lkml.kernel.org/r/1524077799-80690-1-git-send-email-yang.shi@linux.alibaba.com Link: http://lkml.kernel.org/r/1523730291-109696-1-git-send-email-yang.shi@linux.alibaba.com Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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