Messages in this thread Patch in this message | | | Date | Sun, 16 Nov 2014 22:53:29 +0100 | From | Willy Tarreau <> | Subject | [ 01/48] x86_32, entry: Do syscall exit work on badsys |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------ (CVE-2014-4508)
From: Andy Lutomirski <luto@amacapital.net>
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: stable@vger.kernel.org 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> (cherry picked from commit 554086d85e71f30abe46fc014fea31929a7c6a8a) [WT: this fix is incorrect and requires the two following patches] Signed-off-by: Willy Tarreau <w@1wt.eu> --- arch/x86/kernel/entry_32.S | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index c097e7d..40a0d02 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -445,9 +445,10 @@ 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 @@ -702,7 +703,12 @@ 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 -- 1.7.12.2.21.g234cd45.dirty
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