kernel/linux.git/include/linux, branch v4.4.41

exec: Ensure mm->user_ns contains the execed files

2017-01-06T10:16:14+00:00

commit f84df2a6f268de584a201e8911384a2d244876e3 upstream. When the user namespace support was merged the need to prevent ptrace from revealing the contents of an unreadable executable was overlooked. Correct this oversight by ensuring that the executed file or files are in mm->user_ns, by adjusting mm->user_ns. Use the new function privileged_wrt_inode_uidgid to see if the executable is a member of the user namespace, and as such if having CAP_SYS_PTRACE in the user namespace should allow tracing the executable. If not update mm->user_ns to the parent user namespace until an appropriate parent is found. Reported-by: Jann Horn Fixes: 9e4a36ece652 ("userns: Fail exec for suid and sgid binaries with ids outside our user namespace.") Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

ptrace: Capture the ptracer's creds not PT_PTRACE_CAP

2017-01-06T10:16:11+00:00

commit 64b875f7ac8a5d60a4e191479299e931ee949b67 upstream. When the flag PT_PTRACE_CAP was added the PTRACE_TRACEME path was overlooked. This can result in incorrect behavior when an application like strace traces an exec of a setuid executable. Further PT_PTRACE_CAP does not have enough information for making good security decisions as it does not report which user namespace the capability is in. This has already allowed one mistake through insufficient granulariy. I found this issue when I was testing another corner case of exec and discovered that I could not get strace to set PT_PTRACE_CAP even when running strace as root with a full set of caps. This change fixes the above issue with strace allowing stracing as root a setuid executable without disabling setuid. More fundamentaly this change allows what is allowable at all times, by using the correct information in it's decision. Fixes: 4214e42f96d4 ("v2.4.9.11 -> v2.4.9.12") Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

mm: Add a user_ns owner to mm_struct and fix ptrace permission checks

2017-01-06T10:16:11+00:00

commit bfedb589252c01fa505ac9f6f2a3d5d68d707ef4 upstream. During exec dumpable is cleared if the file that is being executed is not readable by the user executing the file. A bug in ptrace_may_access allows reading the file if the executable happens to enter into a subordinate user namespace (aka clone(CLONE_NEWUSER), unshare(CLONE_NEWUSER), or setns(fd, CLONE_NEWUSER). This problem is fixed with only necessary userspace breakage by adding a user namespace owner to mm_struct, captured at the time of exec, so it is clear in which user namespace CAP_SYS_PTRACE must be present in to be able to safely give read permission to the executable. The function ptrace_may_access is modified to verify that the ptracer has CAP_SYS_ADMIN in task->mm->user_ns instead of task->cred->user_ns. This ensures that if the task changes it's cred into a subordinate user namespace it does not become ptraceable. The function ptrace_attach is modified to only set PT_PTRACE_CAP when CAP_SYS_PTRACE is held over task->mm->user_ns. The intent of PT_PTRACE_CAP is to be a flag to note that whatever permission changes the task might go through the tracer has sufficient permissions for it not to be an issue. task->cred->user_ns is always the same as or descendent of mm->user_ns. Which guarantees that having CAP_SYS_PTRACE over mm->user_ns is the worst case for the tasks credentials. To prevent regressions mm->dumpable and mm->user_ns are not considered when a task has no mm. As simply failing ptrace_may_attach causes regressions in privileged applications attempting to read things such as /proc//stat Acked-by: Kees Cook Tested-by: Cyrill Gorcunov Fixes: 8409cca70561 ("userns: allow ptrace from non-init user namespaces") Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman

hotplug: Make register and unregister notifier API symmetric

2016-12-15T16:49:23+00:00

commit 777c6e0daebb3fcefbbd6f620410a946b07ef6d0 upstream. Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its notifiers when HOTPLUG_CPU=y while the registration might succeed even when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap might keep a stale notifier on the list on the manual clean up during the pool tear down and thus corrupt the list. Resulting in the following [ 144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78 [ 144.971337] IP: [] raw_notifier_chain_register+0x1b/0x40 [ 145.122628] Call Trace: [ 145.125086] [] __register_cpu_notifier+0x18/0x20 [ 145.131350] [] zswap_pool_create+0x273/0x400 [ 145.137268] [] __zswap_param_set+0x1fc/0x300 [ 145.143188] [] ? trace_hardirqs_on+0xd/0x10 [ 145.149018] [] ? kernel_param_lock+0x28/0x30 [ 145.154940] [] ? __might_fault+0x4f/0xa0 [ 145.160511] [] zswap_compressor_param_set+0x17/0x20 [ 145.167035] [] param_attr_store+0x5c/0xb0 [ 145.172694] [] module_attr_store+0x1d/0x30 [ 145.178443] [] sysfs_kf_write+0x4f/0x70 [ 145.183925] [] kernfs_fop_write+0x149/0x180 [ 145.189761] [] __vfs_write+0x18/0x40 [ 145.194982] [] vfs_write+0xb2/0x1a0 [ 145.200122] [] SyS_write+0x52/0xa0 [ 145.205177] [] entry_SYSCALL_64_fastpath+0x12/0x17 This can be even triggered manually by changing /sys/module/zswap/parameters/compressor multiple times. Fix this issue by making unregister APIs symmetric to the register so there are no surprises. Fixes: 47e627bc8c9a ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU") Reported-and-tested-by: Yu Zhao Signed-off-by: Michal Hocko Cc: linux-mm@kvack.org Cc: Andrew Morton Cc: Dan Streetman Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

constify iov_iter_count() and iter_is_iovec()

2016-12-10T18:07:25+00:00

commit b57332b4105abf1d518d93886e547ee2f98cd414 upstream. [stable note, need this to prevent build warning in commit a0ac402cfcdc904f9772e1762b3fda112dcc56a0] Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

PCI: Export pcie_find_root_port

2016-12-08T06:15:24+00:00

commit e784930bd645e7df78c66e7872fec282b0620075 upstream. Export pcie_find_root_port() so we can use it outside of PCIe-AER error injection. Signed-off-by: Johannes Thumshirn Signed-off-by: Bjorn Helgaas Signed-off-by: Greg Kroah-Hartman

kasan: update kasan_global for gcc 7

2016-12-08T06:15:24+00:00

commit 045d599a286bc01daa3510d59272440a17b23c2e upstream. kasan_global struct is part of compiler/runtime ABI. gcc revision 241983 has added a new field to kasan_global struct. Update kernel definition of kasan_global struct to include the new field. Without this patch KASAN is broken with gcc 7. Link: http://lkml.kernel.org/r/1479219743-28682-1-git-send-email-dvyukov@google.com Signed-off-by: Dmitry Vyukov Acked-by: Andrey Ryabinin Cc: Alexander Potapenko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

iommu/vt-d: Fix PASID table allocation

2016-12-02T08:09:00+00:00

commit 910170442944e1f8674fd5ddbeeb8ccd1877ea98 upstream. Somehow I ended up with an off-by-three error in calculating the size of the PASID and PASID State tables, which triggers allocations failures as those tables unfortunately have to be physically contiguous. In fact, even the *correct* maximum size of 8MiB is problematic and is wont to lead to allocation failures. Since I have extracted a promise that this *will* be fixed in hardware, I'm happy to limit it on the current hardware to a maximum of 0x20000 PASIDs, which gives us 1MiB tables — still not ideal, but better than before. Reported by Mika Kuoppala and also by Xunlei Pang who submitted a simpler patch to fix only the allocation (and not the free) to the "correct" limit... which was still problematic. Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman

tcp: take care of truncations done by sk_filter()

2016-11-21T09:06:40+00:00

[ Upstream commit ac6e780070e30e4c35bd395acfe9191e6268bdd3 ] With syzkaller help, Marco Grassi found a bug in TCP stack, crashing in tcp_collapse() Root cause is that sk_filter() can truncate the incoming skb, but TCP stack was not really expecting this to happen. It probably was expecting a simple DROP or ACCEPT behavior. We first need to make sure no part of TCP header could be removed. Then we need to adjust TCP_SKB_CB(skb)->end_seq Many thanks to syzkaller team and Marco for giving us a reproducer. Signed-off-by: Eric Dumazet Reported-by: Marco Grassi Reported-by: Vladis Dronov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: add recursion limit to GRO

2016-11-15T06:46:38+00:00

[ Upstream commit fcd91dd449867c6bfe56a81cabba76b829fd05cd ] Currently, GRO can do unlimited recursion through the gro_receive handlers. This was fixed for tunneling protocols by limiting tunnel GRO to one level with encap_mark, but both VLAN and TEB still have this problem. Thus, the kernel is vulnerable to a stack overflow, if we receive a packet composed entirely of VLAN headers. This patch adds a recursion counter to the GRO layer to prevent stack overflow. When a gro_receive function hits the recursion limit, GRO is aborted for this skb and it is processed normally. This recursion counter is put in the GRO CB, but could be turned into a percpu counter if we run out of space in the CB. Thanks to Vladimír Beneš for the initial bug report. Fixes: CVE-2016-7039 Fixes: 9b174d88c257 ("net: Add Transparent Ethernet Bridging GRO support.") Fixes: 66e5133f19e9 ("vlan: Add GRO support for non hardware accelerated vlan") Signed-off-by: Sabrina Dubroca Reviewed-by: Jiri Benc Acked-by: Hannes Frederic Sowa Acked-by: Tom Herbert Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman