• Andrea Arcangeli's avatar
    [PATCH] i386: seccomp fix for auditing/ptrace · 4c7fc722
    Andrea Arcangeli authored
    This is the same issue as ppc64 before, when returning to userland we
    shouldn't re-compute the seccomp check or the task could be killed during
    sigreturn when orig_eax is overwritten by the sigreturn syscall.  This was
    found by Roland.
    
    This was harmless from a security standpoint, but some i686 users reported
    failures with auditing enabled system wide (some distro surprisingly makes
    it the default) and I reproduced it too by keeping the whole workload under
    strace -f.
    
    Patch is tested and works for me under strace -f.
    
    nobody@athlon:~/cpushare> strace -o /tmp/o -f python seccomp_test.py
    make: Nothing to be done for `seccomp_test'.
    Starting computing some malicious bytecode
    init
    load
    start
    stop
    receive_data failure
    kill
    exit_code 0 signal 9
    The malicious bytecode has been killed successfully by seccomp
    Starting computing some safe bytecode
    init
    load
    start
    stop
    174 counts
    kill
    exit_code 0 signal 0
    The seccomp_test.py completed successfully, thank you for testing.
    
    (akpm: collaterally cleaned up a bit of do_syscall_trace() too)
    Signed-off-by: default avatarAndrea Arcangeli <andrea@cpushare.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    4c7fc722
ptrace.c 19.3 KB