[PATCH 3.2 051/152] x86/syscalls/64: Add compat_sys_keyctl for 32-bit userspace

[Ben Hutchings]

3.2.84-rc1 review patch.  If anyone has any objections, please let me know.

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

From: David Howells <dhowells@xxxxxxxxxx>

commit f7d665627e103e82d34306c7d3f6f46f387c0d8b upstream.

x86_64 needs to use compat_sys_keyctl for 32-bit userspace rather than
calling sys_keyctl(). The latter will work in a lot of cases, thereby
hiding the issue.

Reported-by: Stephan Mueller <smueller@xxxxxxxxxx>
Tested-by: Stephan Mueller <smueller@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: keyrings@xxxxxxxxxxxxxxx
Cc: linux-security-module@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/146961615805.14395.5581949237156769439.stgit@xxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
[bwh: Backported to 3.2: compat system call table is in ia32entry.S]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -791,7 +791,7 @@ ia32_sys_call_table:
 	.quad quiet_ni_syscall		/* 285: sys_altroot */
 	.quad sys_add_key
 	.quad sys_request_key
-	.quad sys_keyctl
+	.quad compat_sys_keyctl
 	.quad sys_ioprio_set
 	.quad sys_ioprio_get		/* 290 */
 	.quad sys_inotify_init