From: Andy Lutomirski Date: Mon, 23 Jun 2014 21:22:15 +0000 (-0700) Subject: x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508) X-Git-Tag: submit/tizen_common/20151126.162616~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e07c81dc9d145b706cc5e137ebb64dc663500ad9;p=sdk%2Femulator%2Femulator-kernel.git 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 Reported-by: Toralf Förster Signed-off-by: Andy Lutomirski Link: http://lkml.kernel.org/r/e09c499eade6fc321266dd6b54da7beb28d6991c.1403558229.git.luto@amacapital.net Signed-off-by: H. Peter Anvin Signed-off-by: Greg Kroah-Hartman Origin: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=554086d85e71f30abe46fc014fea31929a7c6a8a Backported-by: Maciej Wereski Signed-off-by: Maciej Wereski Change-Id: I7fbb024771fb7c33ce97006868fb9224e1d19321 --- diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 15a569a47b4d..61b52dbf76e1 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -434,9 +434,10 @@ 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 @@ -691,7 +692,12 @@ 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 /*