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2018-07-17fs, elf: make sure to page align bss in load_elf_libraryOscar Salvador1-3/+2
commit 24962af7e1041b7e50c1bc71d8d10dc678c556b5 upstream. The current code does not make sure to page align bss before calling vm_brk(), and this can lead to a VM_BUG_ON() in __mm_populate() due to the requested lenght not being correctly aligned. Let us make sure to align it properly. Kees: only applicable to CONFIG_USELIB kernels: 32-bit and configured for libc5. Link: http://lkml.kernel.org/r/20180705145539.9627-1-osalvador@techadventures.net Signed-off-by: Oscar Salvador <osalvador@suse.de> Reported-by: syzbot+5dcb560fe12aa5091c06@syzkaller.appspotmail.com Tested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Acked-by: Kees Cook <keescook@chromium.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Nicolas Pitre <nicolas.pitre@linaro.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-21fs, elf: don't complain MAP_FIXED_NOREPLACE unless -EEXIST errorTetsuo Handa1-4/+4
Commit 4ed28639519c ("fs, elf: drop MAP_FIXED usage from elf_map") is printing spurious messages under memory pressure due to map_addr == -ENOMEM. 9794 (a.out): Uhuuh, elf segment at 00007f2e34738000(fffffffffffffff4) requested but the memory is mapped already 14104 (a.out): Uhuuh, elf segment at 00007f34fd76c000(fffffffffffffff4) requested but the memory is mapped already 16843 (a.out): Uhuuh, elf segment at 00007f930ecc7000(fffffffffffffff4) requested but the memory is mapped already Complain only if -EEXIST, and use %px for printing the address. Link: http://lkml.kernel.org/r/201804182307.FAC17665.SFMOFJVFtHOLOQ@I-love.SAKURA.ne.jp Fixes: 4ed28639519c7bad ("fs, elf: drop MAP_FIXED usage from elf_map") is Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Andrei Vagin <avagin@openvz.org> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Kees Cook <keescook@chromium.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Joel Stanley <joel@jms.id.au> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11elf: enforce MAP_FIXED on overlaying elf segmentsMichal Hocko1-3/+10
Anshuman has reported that with "fs, elf: drop MAP_FIXED usage from elf_map" applied, some ELF binaries in his environment fail to start with [ 23.423642] 9148 (sed): Uhuuh, elf segment at 0000000010030000 requested but the memory is mapped already [ 23.423706] requested [10030000, 10040000] mapped [10030000, 10040000] 100073 anon The reason is that the above binary has overlapping elf segments: LOAD 0x0000000000000000 0x0000000010000000 0x0000000010000000 0x0000000000013a8c 0x0000000000013a8c R E 10000 LOAD 0x000000000001fd40 0x000000001002fd40 0x000000001002fd40 0x00000000000002c0 0x00000000000005e8 RW 10000 LOAD 0x0000000000020328 0x0000000010030328 0x0000000010030328 0x0000000000000384 0x00000000000094a0 RW 10000 That binary has two RW LOAD segments, the first crosses a page border into the second 0x1002fd40 (LOAD2-vaddr) + 0x5e8 (LOAD2-memlen) == 0x10030328 (LOAD3-vaddr) Handle this situation by enforcing MAP_FIXED when we establish a temporary brk VMA to handle overlapping segments. All other mappings will still use MAP_FIXED_NOREPLACE. Link: http://lkml.kernel.org/r/20180213100440.GM3443@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Cc: Andrei Vagin <avagin@openvz.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Kees Cook <keescook@chromium.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Joel Stanley <joel@jms.id.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11fs, elf: drop MAP_FIXED usage from elf_mapMichal Hocko1-4/+9
Both load_elf_interp and load_elf_binary rely on elf_map to map segments on a controlled address and they use MAP_FIXED to enforce that. This is however dangerous thing prone to silent data corruption which can be even exploitable. Let's take CVE-2017-1000253 as an example. At the time (before commit eab09532d400: "binfmt_elf: use ELF_ET_DYN_BASE only for PIE") ELF_ET_DYN_BASE was at TASK_SIZE / 3 * 2 which is not that far away from the stack top on 32b (legacy) memory layout (only 1GB away). Therefore we could end up mapping over the existing stack with some luck. The issue has been fixed since then (a87938b2e246: "fs/binfmt_elf.c: fix bug in loading of PIE binaries"), ELF_ET_DYN_BASE moved moved much further from the stack (eab09532d400 and later by c715b72c1ba4: "mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes") and excessive stack consumption early during execve fully stopped by da029c11e6b1 ("exec: Limit arg stack to at most 75% of _STK_LIM"). So we should be safe and any attack should be impractical. On the other hand this is just too subtle assumption so it can break quite easily and hard to spot. I believe that the MAP_FIXED usage in load_elf_binary (et. al) is still fundamentally dangerous. Moreover it shouldn't be even needed. We are at the early process stage and so there shouldn't be unrelated mappings (except for stack and loader) existing so mmap for a given address should succeed even without MAP_FIXED. Something is terribly wrong if this is not the case and we should rather fail than silently corrupt the underlying mapping. Address this issue by changing MAP_FIXED to the newly added MAP_FIXED_NOREPLACE. This will mean that mmap will fail if there is an existing mapping clashing with the requested one without clobbering it. [mhocko@suse.com: fix build] [akpm@linux-foundation.org: coding-style fixes] [avagin@openvz.org: don't use the same value for MAP_FIXED_NOREPLACE and MAP_SYNC] Link: http://lkml.kernel.org/r/20171218184916.24445-1-avagin@openvz.org Link: http://lkml.kernel.org/r/20171213092550.2774-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrei Vagin <avagin@openvz.org> Signed-off-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Acked-by: Kees Cook <keescook@chromium.org> Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com> Cc: Joel Stanley <joel@jms.id.au> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11exec: introduce finalize_exec() before start_thread()Kees Cook1-0/+1
Provide a final callback into fs/exec.c before start_thread() takes over, to handle any last-minute changes, like the coming restoration of the stack limit. Link: http://lkml.kernel.org/r/1518638796-20819-3-git-send-email-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Ben Hutchings <ben.hutchings@codethink.co.uk> Cc: Brad Spengler <spender@grsecurity.net> Cc: Greg KH <greg@kroah.com> Cc: Hugh Dickins <hughd@google.com> Cc: "Jason A. Donenfeld" <Jason@zx2c4.com> Cc: Laura Abbott <labbott@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-07elf: fix NT_FILE integer overflowAlexey Dobriyan1-0/+2
If vm.max_map_count bumped above 2^26 (67+ mil) and system has enough RAM to allocate all the VMAs (~12.8 GB on Fedora 27 with 200-byte VMAs), then it should be possible to overflow 32-bit "size", pass paranoia check, allocate very little vmalloc space and oops while writing into vmalloc guard page... But I didn't test this, only coredump of regular process. Link: http://lkml.kernel.org/r/20180112203427.GA9109@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>
2017-11-16Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds1-2/+13
Pull ARM updates from Russell King: - add support for ELF fdpic binaries on both MMU and noMMU platforms - linker script cleanups - support for compressed .data section for XIP images - discard memblock arrays when possible - various cleanups - atomic DMA pool updates - better diagnostics of missing/corrupt device tree - export information to allow userspace kexec tool to place images more inteligently, so that the device tree isn't overwritten by the booting kernel - make early_printk more efficient on semihosted systems - noMMU cleanups - SA1111 PCMCIA update in preparation for further cleanups * 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (38 commits) ARM: 8719/1: NOMMU: work around maybe-uninitialized warning ARM: 8717/2: debug printch/printascii: translate '\n' to "\r\n" not "\n\r" ARM: 8713/1: NOMMU: Support MPU in XIP configuration ARM: 8712/1: NOMMU: Use more MPU regions to cover memory ARM: 8711/1: V7M: Add support for MPU to M-class ARM: 8710/1: Kconfig: Kill CONFIG_VECTORS_BASE ARM: 8709/1: NOMMU: Disallow MPU for XIP ARM: 8708/1: NOMMU: Rework MPU to be mostly done in C ARM: 8707/1: NOMMU: Update MPU accessors to use cp15 helpers ARM: 8706/1: NOMMU: Move out MPU setup in separate module ARM: 8702/1: head-common.S: Clear lr before jumping to start_kernel() ARM: 8705/1: early_printk: use printascii() rather than printch() ARM: 8703/1: debug.S: move hexbuf to a writable section ARM: add additional table to compressed kernel ARM: decompressor: fix BSS size calculation pcmcia: sa1111: remove special sa1111 mmio accessors pcmcia: sa1111: use sa1111_get_irq() to obtain IRQ resources ARM: better diagnostics with missing/corrupt dtb ARM: 8699/1: dma-mapping: Remove init_dma_coherent_pool_size() ARM: 8698/1: dma-mapping: Mark atomic_pool as __ro_after_init ..
2017-11-03regset: Add support for dynamically sized regsetsDave Martin1-5/+5
Currently the regset API doesn't allow for the possibility that regsets (or at least, the amount of meaningful data in a regset) may change in size. In particular, this results in useless padding being added to coredumps if a regset's current size is smaller than its theoretical maximum size. This patch adds a get_size() function to struct user_regset. Individual regset implementations can implement this function to return the current size of the regset data. A regset_size() function is added to provide callers with an abstract interface for determining the size of a regset without needing to know whether the regset is dynamically sized or not. The only affected user of this interface is the ELF coredump code: This patch ports ELF coredump to dump regsets with their actual size in the coredump. This has no effect except for new regsets that are dynamically sized and provide a get_size() implementation. Signed-off-by: Dave Martin <Dave.Martin@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: H. J. Lu <hjl.tools@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2017-10-03Merge branch 'fdpic' of http://git.linaro.org/people/nicolas.pitre/linux ↵Russell King1-2/+13
into devel-stable This series provides the needed changes to suport the ELF_FDPIC binary format on ARM. Both MMU and non-MMU systems are supported. This format has many advantages over the BFLT format used on MMU-less systems, such as being real ELF that can be parsed by standard tools, can support shared dynamic libs, etc.
2017-09-15Merge branch 'work.set_fs' of ↵Linus Torvalds1-10/+13
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more set_fs removal from Al Viro: "Christoph's 'use kernel_read and friends rather than open-coding set_fs()' series" * 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: unexport vfs_readv and vfs_writev fs: unexport vfs_read and vfs_write fs: unexport __vfs_read/__vfs_write lustre: switch to kernel_write gadget/f_mass_storage: stop messing with the address limit mconsole: switch to kernel_read btrfs: switch write_buf to kernel_write net/9p: switch p9_fd_read to kernel_write mm/nommu: switch do_mmap_private to kernel_read serial2002: switch serial2002_tty_write to kernel_{read/write} fs: make the buf argument to __kernel_write a void pointer fs: fix kernel_write prototype fs: fix kernel_read prototype fs: move kernel_read to fs/read_write.c fs: move kernel_write to fs/read_write.c autofs4: switch autofs4_write to __kernel_write ashmem: switch to ->read_iter
2017-09-11binfmt_elf: don't attempt to load FDPIC binariesNicolas Pitre1-2/+13
On platforms where both ELF and ELF-FDPIC variants are available, the regular ELF loader will happily identify FDPIC binaries as proper ELF and load them without the necessary FDPIC fixups, resulting in an immediate user space crash. Let's prevent binflt_elf from loading those binaries so binfmt_elf_fdpic has a chance to pick them up. For those architectures that don't define elf_check_fdpic(), a default version returning false is provided. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Mickael GUENE <mickael.guene@st.com> Tested-by: Vincent Abriou <vincent.abriou@st.com> Tested-by: Andras Szemzo <szemzo.andras@gmail.com>
2017-09-08Merge tag 'secureexec-v4.14-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull secureexec update from Kees Cook: "This series has the ultimate goal of providing a sane stack rlimit when running set*id processes. To do this, the bprm_secureexec LSM hook is collapsed into the bprm_set_creds hook so the secureexec-ness of an exec can be determined early enough to make decisions about rlimits and the resulting memory layouts. Other logic acting on the secureexec-ness of an exec is similarly consolidated. Capabilities needed some special handling, but the refactoring removed other special handling, so that was a wash" * tag 'secureexec-v4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: exec: Consolidate pdeath_signal clearing exec: Use sane stack rlimit under secureexec exec: Consolidate dumpability logic smack: Remove redundant pdeath_signal clearing exec: Use secureexec for clearing pdeath_signal exec: Use secureexec for setting dumpability LSM: drop bprm_secureexec hook commoncap: Move cap_elevated calculation into bprm_set_creds commoncap: Refactor to remove bprm_secureexec hook smack: Refactor to remove bprm_secureexec hook selinux: Refactor to remove bprm_secureexec hook apparmor: Refactor to remove bprm_secureexec hook binfmt: Introduce secureexec flag exec: Correct comments about "point of no return" exec: Rename bprm->cred_prepared to called_set_creds
2017-09-05fs: fix kernel_read prototypeChristoph Hellwig1-10/+13
Use proper ssize_t and size_t types for the return value and count argument, move the offset last and make it an in/out argument like all other read/write helpers, and make the buf argument a void pointer to get rid of lots of casts in the callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-08-16x86/elf: Remove the unnecessary ADDR_NO_RANDOMIZE checksOleg Nesterov1-2/+1
The ADDR_NO_RANDOMIZE checks in stack_maxrandom_size() and randomize_stack_top() are not required. PF_RANDOMIZE is set by load_elf_binary() only if ADDR_NO_RANDOMIZE is not set, no need to re-check after that. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: stable@vger.kernel.org Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Link: http://lkml.kernel.org/r/20170815154011.GB1076@redhat.com
2017-08-01binfmt: Introduce secureexec flagKees Cook1-1/+1
The bprm_secureexec hook can be moved earlier. Right now, it is called during create_elf_tables(), via load_binary(), via search_binary_handler(), via exec_binprm(). Nearly all (see exception below) state used by bprm_secureexec is created during the bprm_set_creds hook, called from prepare_binprm(). For all LSMs (except commoncaps described next), only the first execution of bprm_set_creds takes any effect (they all check bprm->called_set_creds which prepare_binprm() sets after the first call to the bprm_set_creds hook). However, all these LSMs also only do anything with bprm_secureexec when they detected a secure state during their first run of bprm_set_creds. Therefore, it is functionally identical to move the detection into bprm_set_creds, since the results from secureexec here only need to be based on the first call to the LSM's bprm_set_creds hook. The single exception is that the commoncaps secureexec hook also examines euid/uid and egid/gid differences which are controlled by bprm_fill_uid(), via prepare_binprm(), which can be called multiple times (e.g. binfmt_script, binfmt_misc), and may clear the euid/egid for the final load (i.e. the script interpreter). However, while commoncaps specifically ignores bprm->cred_prepared, and runs its bprm_set_creds hook each time prepare_binprm() may get called, it needs to base the secureexec decision on the final call to bprm_set_creds. As a result, it will need special handling. To begin this refactoring, this adds the secureexec flag to the bprm struct, and calls the secureexec hook during setup_new_exec(). This is safe since all the cred work is finished (and past the point of no return). This explicit call will be removed in later patches once the hook has been removed. Cc: David Howells <dhowells@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: John Johansen <john.johansen@canonical.com> Acked-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: James Morris <james.l.morris@oracle.com>
2017-07-11binfmt_elf: safely increment argv pointersKees Cook1-11/+9
When building the argv/envp pointers, the envp is needlessly pre-incremented instead of just continuing after the argv pointers are finished. In some (likely impossible) race where the strings could be changed from userspace between copy_strings() and here, it might be possible to confuse the envp position. Instead, just use sp like everything else. Link: http://lkml.kernel.org/r/20170622173838.GA43308@beast Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Rik van Riel <riel@redhat.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: Qualys Security Advisory <qsa@qualys.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11binfmt_elf: use ELF_ET_DYN_BASE only for PIEKees Cook1-8/+51
The ELF_ET_DYN_BASE position was originally intended to keep loaders away from ET_EXEC binaries. (For example, running "/lib/ld-linux.so.2 /bin/cat" might cause the subsequent load of /bin/cat into where the loader had been loaded.) With the advent of PIE (ET_DYN binaries with an INTERP Program Header), ELF_ET_DYN_BASE continued to be used since the kernel was only looking at ET_DYN. However, since ELF_ET_DYN_BASE is traditionally set at the top 1/3rd of the TASK_SIZE, a substantial portion of the address space is unused. For 32-bit tasks when RLIMIT_STACK is set to RLIM_INFINITY, programs are loaded above the mmap region. This means they can be made to collide (CVE-2017-1000370) or nearly collide (CVE-2017-1000371) with pathological stack regions. Lowering ELF_ET_DYN_BASE solves both by moving programs below the mmap region in all cases, and will now additionally avoid programs falling back to the mmap region by enforcing MAP_FIXED for program loads (i.e. if it would have collided with the stack, now it will fail to load instead of falling back to the mmap region). To allow for a lower ELF_ET_DYN_BASE, loaders (ET_DYN without INTERP) are loaded into the mmap region, leaving space available for either an ET_EXEC binary with a fixed location or PIE being loaded into mmap by the loader. Only PIE programs are loaded offset from ELF_ET_DYN_BASE, which means architectures can now safely lower their values without risk of loaders colliding with their subsequently loaded programs. For 64-bit, ELF_ET_DYN_BASE is best set to 4GB to allow runtimes to use the entire 32-bit address space for 32-bit pointers. Thanks to PaX Team, Daniel Micay, and Rik van Riel for inspiration and suggestions on how to implement this solution. Fixes: d1fd836dcf00 ("mm: split ET_DYN ASLR from mmap ASLR") Link: http://lkml.kernel.org/r/20170621173201.GA114489@beast Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: Qualys Security Advisory <qsa@qualys.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Grzegorz Andrejczuk <grzegorz.andrejczuk@intel.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Pratyush Anand <panand@redhat.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Will Deacon <will.deacon@arm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-02sched/headers: Prepare to move cputime functionality from <linux/sched.h> ↵Ingo Molnar1-0/+1
into <linux/sched/cputime.h> Introduce a trivial, mostly empty <linux/sched/cputime.h> header to prepare for the moving of cputime functionality out of sched.h. Update all code that relies on these facilities. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar1-0/+1
<linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>Ingo Molnar1-0/+1
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h doing that for them. Note that even if the count where we need to add extra headers seems high, it's still a net win, because <linux/sched.h> is included in over 2,200 files ... Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar1-0/+1
<linux/sched/coredump.h> We are going to split <linux/sched/coredump.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/coredump.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-23powerpc: do not make the entire heap executableDenys Vlasenko1-8/+22
On 32-bit powerpc the ELF PLT sections of binaries (built with --bss-plt, or with a toolchain which defaults to it) look like this: [17] .sbss NOBITS 0002aff8 01aff8 000014 00 WA 0 0 4 [18] .plt NOBITS 0002b00c 01aff8 000084 00 WAX 0 0 4 [19] .bss NOBITS 0002b090 01aff8 0000a4 00 WA 0 0 4 Which results in an ELF load header: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align LOAD 0x019c70 0x00029c70 0x00029c70 0x01388 0x014c4 RWE 0x10000 This is all correct, the load region containing the PLT is marked as executable. Note that the PLT starts at 0002b00c but the file mapping ends at 0002aff8, so the PLT falls in the 0 fill section described by the load header, and after a page boundary. Unfortunately the generic ELF loader ignores the X bit in the load headers when it creates the 0 filled non-file backed mappings. It assumes all of these mappings are RW BSS sections, which is not the case for PPC. gcc/ld has an option (--secure-plt) to not do this, this is said to incur a small performance penalty. Currently, to support 32-bit binaries with PLT in BSS kernel maps *entire brk area* with executable rights for all binaries, even --secure-plt ones. Stop doing that. Teach the ELF loader to check the X bit in the relevant load header and create 0 filled anonymous mappings that are executable if the load header requests that. Test program showing the difference in /proc/$PID/maps: int main() { char buf[16*1024]; char *p = malloc(123); /* make "[heap]" mapping appear */ int fd = open("/proc/self/maps", O_RDONLY); int len = read(fd, buf, sizeof(buf)); write(1, buf, len); printf("%p\n", p); return 0; } Compiled using: gcc -mbss-plt -m32 -Os test.c -otest Unpatched ppc64 kernel: 00100000-00120000 r-xp 00000000 00:00 0 [vdso] 0fe10000-0ffd0000 r-xp 00000000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffd0000-0ffe0000 r--p 001b0000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffe0000-0fff0000 rw-p 001c0000 fd:00 67898094 /usr/lib/libc-2.17.so 10000000-10010000 r-xp 00000000 fd:00 100674505 /home/user/test 10010000-10020000 r--p 00000000 fd:00 100674505 /home/user/test 10020000-10030000 rw-p 00010000 fd:00 100674505 /home/user/test 10690000-106c0000 rwxp 00000000 00:00 0 [heap] f7f70000-f7fa0000 r-xp 00000000 fd:00 67898089 /usr/lib/ld-2.17.so f7fa0000-f7fb0000 r--p 00020000 fd:00 67898089 /usr/lib/ld-2.17.so f7fb0000-f7fc0000 rw-p 00030000 fd:00 67898089 /usr/lib/ld-2.17.so ffa90000-ffac0000 rw-p 00000000 00:00 0 [stack] 0x10690008 Patched ppc64 kernel: 00100000-00120000 r-xp 00000000 00:00 0 [vdso] 0fe10000-0ffd0000 r-xp 00000000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffd0000-0ffe0000 r--p 001b0000 fd:00 67898094 /usr/lib/libc-2.17.so 0ffe0000-0fff0000 rw-p 001c0000 fd:00 67898094 /usr/lib/libc-2.17.so 10000000-10010000 r-xp 00000000 fd:00 100674505 /home/user/test 10010000-10020000 r--p 00000000 fd:00 100674505 /home/user/test 10020000-10030000 rw-p 00010000 fd:00 100674505 /home/user/test 10180000-101b0000 rw-p 00000000 00:00 0 [heap] ^^^^ this has changed f7c60000-f7c90000 r-xp 00000000 fd:00 67898089 /usr/lib/ld-2.17.so f7c90000-f7ca0000 r--p 00020000 fd:00 67898089 /usr/lib/ld-2.17.so f7ca0000-f7cb0000 rw-p 00030000 fd:00 67898089 /usr/lib/ld-2.17.so ff860000-ff890000 rw-p 00000000 00:00 0 [stack] 0x10180008 The patch was originally posted in 2012 by Jason Gunthorpe and apparently ignored: https://lkml.org/lkml/2012/9/30/138 Lightly run-tested. Link: http://lkml.kernel.org/r/20161215131950.23054-1-dvlasenk@redhat.com Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Tested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Florian Weimer <fweimer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-01fs/binfmt: Convert obsolete cputime type to nsecsFrederic Weisbecker1-16/+10
Use the new nsec based cputime accessors as part of the whole cputime conversion from cputime_t to nsecs. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-12-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01sched/cputime: Convert task/group cputime to nsecsFrederic Weisbecker1-2/+9
Now that most cputime readers use the transition API which return the task cputime in old style cputime_t, we can safely store the cputime in nsecs. This will eventually make cputime statistics less opaque and more granular. Back and forth convertions between cputime_t and nsecs in order to deal with cputime_t random granularity won't be needed anymore. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-8-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01sched/cputime: Introduce special task_cputime_t() API to return old-typed ↵Frederic Weisbecker1-3/+3
cputime This API returns a task's cputime in cputime_t in order to ease the conversion of cputime internals to use nsecs units instead. Blindly converting all cputime readers to use this API now will later let us convert more smoothly and step by step all these places to use the new nsec based cputime. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1485832191-26889-7-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-15coredump: Ensure proper size of sparse core filesDave Kleikamp1-0/+1
If the last section of a core file ends with an unmapped or zero page, the size of the file does not correspond with the last dump_skip() call. gdb complains that the file is truncated and can be confusing to users. After all of the vma sections are written, make sure that the file size is no smaller than the current file position. This problem can be demonstrated with gdb's bigcore testcase on the sparc architecture. Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds1-1/+1
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-13binfmt_elf: use vmalloc() for allocation of vma_fileszJason Baron1-2/+4
We have observed page allocations failures of order 4 during core dump while trying to allocate vma_filesz. This results in a useless core file of size 0. To improve reliability use vmalloc(). Note that the vmalloc() allocation is bounded by sysctl_max_map_count, which is 65,530 by default. So with a 4k page size, and 8 bytes per seg, this is a max of 128 pages or an order 7 allocation. Other parts of the core dump path, such as fill_files_note() are already using vmalloc() for presumably similar reasons. Link: http://lkml.kernel.org/r/1479745791-17611-1-git-send-email-jbaron@akamai.com Signed-off-by: Jason Baron <jbaron@akamai.com> 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>
2016-09-14x86/coredump: Use pr_reg size, rather that TIF_IA32 flagDmitry Safonov1-15/+8
Killed PR_REG_SIZE and PR_REG_PTR macro as we can get regset size from regset view. I wish I could also kill PRSTATUS_SIZE nicely. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com> Cc: 0x7f454c46@gmail.com Cc: linux-mm@kvack.org Cc: luto@kernel.org Cc: gorcunov@openvz.org Cc: xemul@virtuozzo.com Link: http://lkml.kernel.org/r/20160905133308.28234-5-dsafonov@virtuozzo.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-08-31binfmt_elf: switch to new creds when switching to new mmLinus Torvalds1-1/+1
We used to delay switching to the new credentials until after we had mapped the executable (and possible elf interpreter). That was kind of odd to begin with, since the new executable will actually then _run_ with the new creds, but whatever. The bigger problem was that we also want to make sure that we turn off prof events and tracing before we start mapping the new executable state. So while this is a cleanup, it's also a fix for a possible information leak. Reported-by: Robert Święcki <robert@swiecki.net> Tested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: David Howells <dhowells@redhat.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-03binfmt_elf: fix calculations for bss paddingKees Cook1-16/+18
A double-bug exists in the bss calculation code, where an overflow can happen in the "last_bss - elf_bss" calculation, but vm_brk internally aligns the argument, underflowing it, wrapping back around safe. We shouldn't depend on these bugs staying in sync, so this cleans up the bss padding handling to avoid the overflow. This moves the bss padzero() before the last_bss > elf_bss case, since the zero-filling of the ELF_PAGE should have nothing to do with the relationship of last_bss and elf_bss: any trailing portion should be zeroed, and a zero size is already handled by padzero(). Then it handles the math on elf_bss vs last_bss correctly. These need to both be ELF_PAGE aligned to get the comparison correct, since that's the expected granularity of the mappings. Since elf_bss already had alignment-based padding happen in padzero(), the "start" of the new vm_brk() should be moved forward as done in the original code. However, since the "end" of the vm_brk() area will already become PAGE_ALIGNed in vm_brk() then last_bss should get aligned here to avoid hiding it as a side-effect. Additionally makes a cosmetic change to the initial last_bss calculation so it's easier to read in comparison to the load_addr calculation above it (i.e. the only difference is p_filesz vs p_memsz). Link: http://lkml.kernel.org/r/1468014494-25291-2-git-send-email-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Reported-by: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Ismael Ripoll Ripoll <iripoll@upv.es> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Chen Gang <gang.chen.5i5j@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-08coredump: fix dumping through pipesMateusz Guzik1-1/+1
The offset in the core file used to be tracked with ->written field of the coredump_params structure. The field was retired in favour of file->f_pos. However, ->f_pos is not maintained for pipes which leads to breakage. Restore explicit tracking of the offset in coredump_params. Introduce ->pos field for this purpose since ->written was already reused. Fixes: a00839395103 ("get rid of coredump_params->written"). Reported-by: Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-05-28mm: remove more IS_ERR_VALUE abusesLinus Torvalds1-6/+5
The do_brk() and vm_brk() return value was "unsigned long" and returned the starting address on success, and an error value on failure. The reasons are entirely historical, and go back to it basically behaving like the mmap() interface does. However, nobody actually wanted that interface, and it causes totally pointless IS_ERR_VALUE() confusion. What every single caller actually wants is just the simpler integer return of zero for success and negative error number on failure. So just convert to that much clearer and more common calling convention, and get rid of all the IS_ERR_VALUE() uses wrt vm_brk(). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-24mm, elf: handle vm_brk errorMichal Hocko1-2/+5
load_elf_library doesn't handle vm_brk failure although nothing really indicates it cannot do that because the function is allowed to fail due to vm_mmap failures already. This might be not a problem now but later patch will make vm_brk killable (resp. mmap_sem for write waiting will become killable) and so the failure will be more probable. Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-18Merge branch 'work.misc' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs cleanups from Al Viro: "Assorted cleanups and fixes all over the place" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: coredump: only charge written data against RLIMIT_CORE coredump: get rid of coredump_params->written ecryptfs_lookup(): try either only encrypted or plaintext name ecryptfs: avoid multiple aliases for directories bpf: reject invalid names right in ->lookup() __d_alloc(): treat NULL name as QSTR("/", 1) mtd: switch ubi_open_volume_path() to vfs_stat() mtd: switch open_mtd_by_chdev() to use of vfs_stat()
2016-05-12coredump: get rid of coredump_params->writtenOmar Sandoval1-1/+1
cprm->written is redundant with cprm->file->f_pos, so use that instead. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-1/+1
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-27mm: ASLR: use get_random_long()Daniel Cashman1-1/+1
Replace calls to get_random_int() followed by a cast to (unsigned long) with calls to get_random_long(). Also address shifting bug which, in case of x86 removed entropy mask for mmap_rnd_bits values > 31 bits. Signed-off-by: Daniel Cashman <dcashman@android.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: David S. Miller <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Nick Kralevich <nnk@google.com> Cc: Jeff Vander Stoep <jeffv@google.com> Cc: Mark Salyzyn <salyzyn@android.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-20ELF: Also pass any interpreter's file header to `arch_check_elf'Maciej W. Rozycki1-1/+5
Also pass any interpreter's file header to `arch_check_elf' so that any architecture handler can have a look at it if needed. Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Acked-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Matthew Fortune <Matthew.Fortune@imgtec.com> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11478/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-11-11Merge branch 'for-linus-2' of ↵Linus Torvalds1-6/+6
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs update from Al Viro: - misc stable fixes - trivial kernel-doc and comment fixups - remove never-used block_page_mkwrite() wrapper function, and rename the function that is _actually_ used to not have double underscores. * 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: 9p: cache.h: Add #define of include guard vfs: remove stale comment in inode_operations vfs: remove unused wrapper block_page_mkwrite() binfmt_elf: Correct `arch_check_elf's description fs: fix writeback.c kernel-doc warnings fs: fix inode.c kernel-doc warning fs/pipe.c: return error code rather than 0 in pipe_write() fs/pipe.c: preserve alloc_file() error code binfmt_elf: Don't clobber passed executable's file header FS-Cache: Handle a write to the page immediately beyond the EOF marker cachefiles: perform test on s_blocksize when opening cache file. FS-Cache: Don't override netfs's primary_index if registering failed FS-Cache: Increase reference of parent after registering, netfs success debugfs: fix refcount imbalance in start_creating
2015-11-11binfmt_elf: Correct `arch_check_elf's descriptionMaciej W. Rozycki1-1/+1
Correct `arch_check_elf's description, mistakenly copied and pasted from `arch_elf_pt_proc'. Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-11binfmt_elf: Don't clobber passed executable's file headerMaciej W. Rozycki1-5/+5
Do not clobber the buffer space passed from `search_binary_handler' and originally preloaded by `prepare_binprm' with the executable's file header by overwriting it with its interpreter's file header. Instead keep the buffer space intact and directly use the data structure locally allocated for the interpreter's file header, fixing a bug introduced in 2.1.14 with loadable module support (linux-mips.org commit beb11695 [Import of Linux/MIPS 2.1.14], predating kernel.org repo's history). Adjust the amount of data read from the interpreter's file accordingly. This was not an issue before loadable module support, because back then `load_elf_binary' was executed only once for a given ELF executable, whether the function succeeded or failed. With loadable module support supported and enabled, upon a failure of `load_elf_binary' -- which may for example be caused by architecture code rejecting an executable due to a missing hardware feature requested in the file header -- a module load is attempted and then the function reexecuted by `search_binary_handler'. With the executable's file header replaced with its interpreter's file header the executable can then be erroneously accepted in this subsequent attempt. Cc: stable@vger.kernel.org # all the way back Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-09coredump: add DAX filtering for ELF coredumpsRoss Zwisler1-0/+10
Add two new flags to the existing coredump mechanism for ELF files to allow us to explicitly filter DAX mappings. This is desirable because DAX mappings, like hugetlb mappings, have the potential to be very large. Update the coredump_filter documentation in Documentation/filesystems/proc.txt so that it addresses the new DAX coredump flags. Also update the documented default value of coredump_filter to be consistent with the core(5) man page. The documentation being updated talks about bit 4, Dump ELF headers, which is enabled if CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is turned on in the kernel config. This kernel config option defaults to "y" if both ELF binaries and coredump are enabled. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2015-07-05Merge branch 'for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
2015-06-24vfs: add file_path() helperMiklos Szeredi1-2/+2
Turn d_path(&file->f_path, ...); into file_path(file, ...); Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-29fs/binfmt_elf.c:load_elf_binary(): return -EINVAL on zero-length mappingsAndrew Morton1-1/+1
load_elf_binary() returns `retval', not `error'. Fixes: a87938b2e246b81b4fb ("fs/binfmt_elf.c: fix bug in loading of PIE binaries") Reported-by: James Hogan <james.hogan@imgtec.com> Cc: Michael Davidson <md@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZEKees Cook1-3/+1
The arch_randomize_brk() function is used on several architectures, even those that don't support ET_DYN ASLR. To avoid bulky extern/#define tricks, consolidate the support under CONFIG_ARCH_HAS_ELF_RANDOMIZE for the architectures that support it, while still handling CONFIG_COMPAT_BRK. Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: "David A. Long" <dave.long@linaro.org> Cc: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Arun Chandran <achandran@mvista.com> Cc: Yann Droneaud <ydroneaud@opteya.com> Cc: Min-Hua Chen <orca.chen@gmail.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Vineeth Vijayan <vvijayan@mvista.com> Cc: Jeff Bailey <jeffbailey@google.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Behan Webster <behanw@converseincode.com> Cc: Ismael Ripoll <iripoll@upv.es> Cc: Jan-Simon Mller <dl9pf@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15mm: split ET_DYN ASLR from mmap ASLRKees Cook1-14/+4
This fixes the "offset2lib" weakness in ASLR for arm, arm64, mips, powerpc, and x86. The problem is that if there is a leak of ASLR from the executable (ET_DYN), it means a leak of shared library offset as well (mmap), and vice versa. Further details and a PoC of this attack is available here: http://cybersecurity.upv.es/attacks/offset2lib/offset2lib.html With this patch, a PIE linked executable (ET_DYN) has its own ASLR region: $ ./show_mmaps_pie 54859ccd6000-54859ccd7000 r-xp ... /tmp/show_mmaps_pie 54859ced6000-54859ced7000 r--p ... /tmp/show_mmaps_pie 54859ced7000-54859ced8000 rw-p ... /tmp/show_mmaps_pie 7f75be764000-7f75be91f000 r-xp ... /lib/x86_64-linux-gnu/libc.so.6 7f75be91f000-7f75beb1f000 ---p ... /lib/x86_64-linux-gnu/libc.so.6 7f75beb1f000-7f75beb23000 r--p ... /lib/x86_64-linux-gnu/libc.so.6 7f75beb23000-7f75beb25000 rw-p ... /lib/x86_64-linux-gnu/libc.so.6 7f75beb25000-7f75beb2a000 rw-p ... 7f75beb2a000-7f75beb4d000 r-xp ... /lib64/ld-linux-x86-64.so.2 7f75bed45000-7f75bed46000 rw-p ... 7f75bed46000-7f75bed47000 r-xp ... 7f75bed47000-7f75bed4c000 rw-p ... 7f75bed4c000-7f75bed4d000 r--p ... /lib64/ld-linux-x86-64.so.2 7f75bed4d000-7f75bed4e000 rw-p ... /lib64/ld-linux-x86-64.so.2 7f75bed4e000-7f75bed4f000 rw-p ... 7fffb3741000-7fffb3762000 rw-p ... [stack] 7fffb377b000-7fffb377d000 r--p ... [vvar] 7fffb377d000-7fffb377f000 r-xp ... [vdso] The change is to add a call the newly created arch_mmap_rnd() into the ELF loader for handling ET_DYN ASLR in a separate region from mmap ASLR, as was already done on s390. Removes CONFIG_BINFMT_ELF_RANDOMIZE_PIE, which is no longer needed. Signed-off-by: Kees Cook <keescook@chromium.org> Reported-by: Hector Marco-Gisbert <hecmargi@upv.es> Cc: Russell King <linux@arm.linux.org.uk> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: "David A. Long" <dave.long@linaro.org> Cc: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Arun Chandran <achandran@mvista.com> Cc: Yann Droneaud <ydroneaud@opteya.com> Cc: Min-Hua Chen <orca.chen@gmail.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Alex Smith <alex@alex-smith.me.uk> Cc: Markos Chandras <markos.chandras@imgtec.com> Cc: Vineeth Vijayan <vvijayan@mvista.com> Cc: Jeff Bailey <jeffbailey@google.com> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Behan Webster <behanw@converseincode.com> Cc: Ismael Ripoll <iripoll@upv.es> Cc: Jan-Simon Mller <dl9pf@gmx.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-04-15fs/binfmt_elf.c: fix bug in loading of PIE binariesMichael Davidson1-1/+8
With CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE enabled, and a normal top-down address allocation strategy, load_elf_binary() will attempt to map a PIE binary into an address range immediately below mm->mmap_base. Unfortunately, load_elf_ binary() does not take account of the need to allocate sufficient space for the entire binary which means that, while the first PT_LOAD segment is mapped below mm->mmap_base, the subsequent PT_LOAD segment(s) end up being mapped above mm->mmap_base into the are that is supposed to be the "gap" between the stack and the binary. Since the size of the "gap" on x86_64 is only guaranteed to be 128MB this means that binaries with large data segments > 128MB can end up mapping part of their data segment over their stack resulting in corruption of the stack (and the data segment once the binary starts to run). Any PIE binary with a data segment > 128MB is vulnerable to this although address randomization means that the actual gap between the stack and the end of the binary is normally greater than 128MB. The larger the data segment of the binary the higher the probability of failure. Fix this by calculating the total size of the binary in the same way as load_elf_interp(). Signed-off-by: Michael Davidson <md@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-02-19x86, mm/ASLR: Fix stack randomization on 64-bit systemsHector Marco-Gisbert1-2/+3
The issue is that the stack for processes is not properly randomized on 64 bit architectures due to an integer overflow. The affected function is randomize_stack_top() in file "fs/binfmt_elf.c": static unsigned long randomize_stack_top(unsigned long stack_top) { unsigned int random_variable = 0; if ((current->flags & PF_RANDOMIZE) && !(current->personality & ADDR_NO_RANDOMIZE)) { random_variable = get_random_int() & STACK_RND_MASK; random_variable <<= PAGE_SHIFT; } return PAGE_ALIGN(stack_top) + random_variable; return PAGE_ALIGN(stack_top) - random_variable; } Note that, it declares the "random_variable" variable as "unsigned int". Since the result of the shifting operation between STACK_RND_MASK (which is 0x3fffff on x86_64, 22 bits) and PAGE_SHIFT (which is 12 on x86_64): random_variable <<= PAGE_SHIFT; then the two leftmost bits are dropped when storing the result in the "random_variable". This variable shall be at least 34 bits long to hold the (22+12) result. These two dropped bits have an impact on the entropy of process stack. Concretely, the total stack entropy is reduced by four: from 2^28 to 2^30 (One fourth of expected entropy). This patch restores back the entropy by correcting the types involved in the operations in the functions randomize_stack_top() and stack_maxrandom_size(). The successful fix can be tested with: $ for i in `seq 1 10`; do cat /proc/self/maps | grep stack; done 7ffeda566000-7ffeda587000 rw-p 00000000 00:00 0 [stack] 7fff5a332000-7fff5a353000 rw-p 00000000 00:00 0 [stack] 7ffcdb7a1000-7ffcdb7c2000 rw-p 00000000 00:00 0 [stack] 7ffd5e2c4000-7ffd5e2e5000 rw-p 00000000 00:00 0 [stack] ... Once corrected, the leading bytes should be between 7ffc and 7fff, rather than always being 7fff. Signed-off-by: Hector Marco-Gisbert <hecmargi@upv.es> Signed-off-by: Ismael Ripoll <iripoll@upv.es> [ Rebased, fixed 80 char bugs, cleaned up commit message, added test example and CVE ] Signed-off-by: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Fixes: CVE-2015-1593 Link: http://lkml.kernel.org/r/20150214173350.GA18393@www.outflux.net Signed-off-by: Borislav Petkov <bp@suse.de>
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