Messages in this thread Patch in this message | | | Date | Mon, 10 Nov 2014 01:48:31 -0800 | From | tip-bot for Andy Lutomirski <> | Subject | [tip:x86/vdso] x86_64/vsyscall: Restore orig_ax after vsyscall seccomp |
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Commit-ID: 26893107aa717cd11010f0c278d02535defa1ac9 Gitweb: http://git.kernel.org/tip/26893107aa717cd11010f0c278d02535defa1ac9 Author: Andy Lutomirski <luto@amacapital.net> AuthorDate: Tue, 4 Nov 2014 15:36:50 -0800 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Mon, 10 Nov 2014 10:46:35 +0100
x86_64/vsyscall: Restore orig_ax after vsyscall seccomp
The vsyscall emulation code sets orig_ax for seccomp's benefit, but it forgot to set it back.
I'm not sure that this is observable at all, but it could cause confusion to various /proc or ptrace users, and it's possible that it could cause minor artifacts if a signal were to be delivered on return from vsyscall emulation.
Signed-off-by: Andy Lutomirski <luto@amacapital.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/cdc6a564517a4df09235572ee5f530ccdcf933f7.1415144089.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/vsyscall_64.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 7d9eb4b..2dcc6ff 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -206,6 +206,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) "seccomp tried to change syscall nr or ip"); do_exit(SIGSYS); } + regs->orig_ax = -1; if (tmp) goto do_ret; /* skip requested */
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