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| author | Kees Cook <keescook@chromium.org> | 2017-03-23 15:46:16 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-08 09:30:35 +0200 |
| commit | 673dfb6d1bb4e16cd6416f6a9a90c58908539bcf (patch) | |
| tree | f8b981f55d3aedbd35c745dae920b6765e6eb57d /lib/syscall.c | |
| parent | af5ef6dafea0e9a9f6bd40ebf12c89366cd530ff (diff) | |
| download | linux-stable-673dfb6d1bb4e16cd6416f6a9a90c58908539bcf.tar.gz linux-stable-673dfb6d1bb4e16cd6416f6a9a90c58908539bcf.tar.bz2 linux-stable-673dfb6d1bb4e16cd6416f6a9a90c58908539bcf.zip | |
lib/syscall: Clear return values when no stack
commit 854fbd6e5f60fe99e8e3a569865409fca378f143 upstream.
Commit:
aa1f1a639621 ("lib/syscall: Pin the task stack in collect_syscall()")
... added logic to handle a process stack not existing, but left sp and pc
uninitialized, which can be later reported via /proc/$pid/syscall for zombie
processes, potentially exposing kernel memory to userspace.
Zombie /proc/$pid/syscall before:
-1 0xffffffff9a060100 0xffff92f42d6ad900
Zombie /proc/$pid/syscall after:
-1 0x0 0x0
Reported-by: Robert Święcki <robert@swiecki.net>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: aa1f1a639621 ("lib/syscall: Pin the task stack in collect_syscall()")
Link: http://lkml.kernel.org/r/20170323224616.GA92694@beast
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/syscall.c')
| -rw-r--r-- | lib/syscall.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/syscall.c b/lib/syscall.c index 63239e097b13..a72cd0996230 100644 --- a/lib/syscall.c +++ b/lib/syscall.c @@ -11,6 +11,7 @@ static int collect_syscall(struct task_struct *target, long *callno, if (!try_get_task_stack(target)) { /* Task has no stack, so the task isn't in a syscall. */ + *sp = *pc = 0; *callno = -1; return 0; } |