summaryrefslogtreecommitdiffstats
path: root/drivers/scsi
diff options
context:
space:
mode:
authorJann Horn <jannh@google.com>2018-10-05 15:51:58 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-05 16:32:05 -0700
commitf8a00cef17206ecd1b30d3d9f99e10d9fa707aa7 (patch)
tree14c272777b2abd73875efe44b90741408913d334 /drivers/scsi
parent20916d4636a9b3c1bf562b305f91d126771edaf9 (diff)
downloadlinux-f8a00cef17206ecd1b30d3d9f99e10d9fa707aa7.tar.gz
linux-f8a00cef17206ecd1b30d3d9f99e10d9fa707aa7.tar.bz2
linux-f8a00cef17206ecd1b30d3d9f99e10d9fa707aa7.zip
proc: restrict kernel stack dumps to root
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>
Diffstat (limited to 'drivers/scsi')
0 files changed, 0 insertions, 0 deletions