Description of problem: On x86-64, a 32-bit process (TIFIA32) can switch to 64-bit mode with ljmp, and then use the "syscall" instruction to make a 64-bit system call. A 64-bit process make a 32-bit system call with int $0x80.

In both these cases, auditsyscallentry() will use the wrong system call number table and the wrong system call argument registers. This could be used to circumvent a syscall audit configuration that filters based on the syscall numbers or argument details.

References: http://scary.beasts.org/security/CESA-2009-001.html http://scary.beasts.org/security/CESA-2009-004.html https://bugzilla.redhat.com/showbug.cgi?id=487255 http://lkml.org/lkml/2009/2/27/451 summary http://lkml.org/lkml/2009/2/27/452 syscall-audit