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| author | Kees Cook <keescook@chromium.org> | 2018-04-11 01:34:53 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-04-11 19:28:37 +0200 |
| commit | 8f2af155b513583e8b149a384551f13e1ac5dc72 (patch) | |
| tree | e9a274d97cf4a21f4189343a46b3cd0ddb0e4c79 /include | |
| parent | seq_file: account everything to kmemcg (diff) | |
| download | linux-8f2af155b513583e8b149a384551f13e1ac5dc72.tar.xz linux-8f2af155b513583e8b149a384551f13e1ac5dc72.zip | |
exec: pass stack rlimit into mm layout functions
Patch series "exec: Pin stack limit during exec".
Attempts to solve problems with the stack limit changing during exec
continue to be frustrated[1][2]. In addition to the specific issues
around the Stack Clash family of flaws, Andy Lutomirski pointed out[3]
other places during exec where the stack limit is used and is assumed to
be unchanging. Given the many places it gets used and the fact that it
can be manipulated/raced via setrlimit() and prlimit(), I think the only
way to handle this is to move away from the "current" view of the stack
limit and instead attach it to the bprm, and plumb this down into the
functions that need to know the stack limits. This series implements
the approach.
[1] 04e35f4495dd ("exec: avoid RLIMIT_STACK races with prlimit()")
[2] 779f4e1c6c7c ("Revert "exec: avoid RLIMIT_STACK races with prlimit()"")
[3] to security@kernel.org, "Subject: existing rlimit races?"
This patch (of 3):
Since it is possible that the stack rlimit can change externally during
exec (either via another thread calling setrlimit() or another process
calling prlimit()), provide a way to pass the rlimit down into the
per-architecture mm layout functions so that the rlimit can stay in the
bprm structure instead of sitting in the signal structure until exec is
finalized.
Link: http://lkml.kernel.org/r/1518638796-20819-2-git-send-email-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Hugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Greg KH <greg@kroah.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched/mm.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 9806184bb3d5..2c570cd934af 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -104,7 +104,8 @@ static inline void mm_update_next_owner(struct mm_struct *mm) #endif /* CONFIG_MEMCG */ #ifdef CONFIG_MMU -extern void arch_pick_mmap_layout(struct mm_struct *mm); +extern void arch_pick_mmap_layout(struct mm_struct *mm, + struct rlimit *rlim_stack); extern unsigned long arch_get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); @@ -113,7 +114,8 @@ arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); #else -static inline void arch_pick_mmap_layout(struct mm_struct *mm) {} +static inline void arch_pick_mmap_layout(struct mm_struct *mm, + struct rlimit *rlim_stack) {} #endif static inline bool in_vfork(struct task_struct *tsk) |