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authorJan Beulich <JBeulich@novell.com>2009-10-26 15:20:29 +0000
committerIngo Molnar <mingo@elte.hu>2009-10-26 16:23:26 +0100
commit81766741fe1eee3884219e8daaf03f466f2ed52f (patch)
tree0afde40852f608ed101d03a83ef49ef74ccbb434
parent72ed7de74e8f0fad0d8e567ae1f987b740accb3f (diff)
x86-64: Fix register leak in 32-bit syscall audting
Restoring %ebp after the call to audit_syscall_exit() is not only unnecessary (because the register didn't get clobbered), but in the sysenter case wasn't even doing the right thing: It loaded %ebp from a location below the top of stack (RBP < ARGOFFSET), i.e. arbitrary kernel data got passed back to user mode in the register. Signed-off-by: Jan Beulich <jbeulich@novell.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: <stable@kernel.org> LKML-Reference: <4AE5CC4D020000780001BD13@vpn.id2.novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--arch/x86/ia32/ia32entry.S5
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
index 1733f9f65e8..581b0568fe1 100644
--- a/arch/x86/ia32/ia32entry.S
+++ b/arch/x86/ia32/ia32entry.S
@@ -204,7 +204,7 @@ sysexit_from_sys_call:
movl RDI-ARGOFFSET(%rsp),%r8d /* reload 5th syscall arg */
.endm
- .macro auditsys_exit exit,ebpsave=RBP
+ .macro auditsys_exit exit
testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10)
jnz ia32_ret_from_sys_call
TRACE_IRQS_ON
@@ -217,7 +217,6 @@ sysexit_from_sys_call:
call audit_syscall_exit
GET_THREAD_INFO(%r10)
movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall return value */
- movl \ebpsave-ARGOFFSET(%rsp),%ebp /* reload user register value */
movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
cli
TRACE_IRQS_OFF
@@ -351,7 +350,7 @@ cstar_auditsys:
jmp cstar_dispatch
sysretl_audit:
- auditsys_exit sysretl_from_sys_call, RCX /* user %ebp in RCX slot */
+ auditsys_exit sysretl_from_sys_call
#endif
cstar_tracesys: