[patch 69/96] x86-64: syscall-audit: fix 32/64 syscall hole

Greg KH
2009-03-14T00:42:46Z

[-- Attachment #1: x86-64-syscall-audit-fix-32-64-syscall-hole.patch --]
[-- Type: text/plain, Size: 1241 bytes --]

2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------

From: Roland McGrath <roland@redhat.com>

commit ccbe495caa5e604b04d5a31d7459a6f6a76a756c upstream.

On x86-64, a 32-bit process (TIF_IA32) can switch to 64-bit mode with
ljmp, and then use the "syscall" instruction to make a 64-bit system
call. A 64-bit process make a 32-bit system call with int $0x80.

In both these cases, audit_syscall_entry() will use the wrong system
call number table and the wrong system call argument registers. This
could be used to circumvent a syscall audit configuration that filters
based on the syscall numbers or argument details.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/kernel/ptrace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -1403,7 +1403,7 @@ static void syscall_trace(struct pt_regs
#ifdef CONFIG_X86_32
# define IS_IA32 1
#elif defined CONFIG_IA32_EMULATION
-# define IS_IA32 test_thread_flag(TIF_IA32)
+# define IS_IA32 is_compat_task()
#else
# define IS_IA32 0
#endif