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authorAndy Lutomirski <luto@amacapital.net>2014-06-23 14:22:15 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-30 20:01:34 -0700
commitd3007333170435135f0620fb52386aad3fb2a14f (patch)
tree49119ee6b35c669467978312f5c54900da80516e
parent3b0d0894ebaede13481207275e075f2975fb30a3 (diff)
x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508)
commit 554086d85e71f30abe46fc014fea31929a7c6a8a upstream. The bad syscall nr paths are their own incomprehensible route through the entry control flow. Rearrange them to work just like syscalls that return -ENOSYS. This fixes an OOPS in the audit code when fast-path auditing is enabled and sysenter gets a bad syscall nr (CVE-2014-4508). This has probably been broken since Linux 2.6.27: af0575bba0 i386 syscall audit fast-path Cc: Roland McGrath <roland@redhat.com> Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Link: http://lkml.kernel.org/r/e09c499eade6fc321266dd6b54da7beb28d6991c.1403558229.git.luto@amacapital.net Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/kernel/entry_32.S10
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index 3a463f9dba06..e1e7f9c831da 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -426,9 +426,10 @@ sysenter_past_esp:
jnz sysenter_audit
sysenter_do_call:
cmpl $(NR_syscalls), %eax
- jae syscall_badsys
+ jae sysenter_badsys
call *sys_call_table(,%eax,4)
movl %eax,PT_EAX(%esp)
+sysenter_after_call:
LOCKDEP_SYS_EXIT
DISABLE_INTERRUPTS(CLBR_ANY)
TRACE_IRQS_OFF
@@ -678,7 +679,12 @@ END(syscall_fault)
syscall_badsys:
movl $-ENOSYS,PT_EAX(%esp)
- jmp resume_userspace
+ jmp syscall_exit
+END(syscall_badsys)
+
+sysenter_badsys:
+ movl $-ENOSYS,PT_EAX(%esp)
+ jmp sysenter_after_call
END(syscall_badsys)
CFI_ENDPROC
/*