• Kees Cook's avatar
    tools/testing/selftests/sysctl: validate sysctl_writes_strict · 24fe831c
    Kees Cook authored
    This adds several behavioral tests to sysctl string and number writing
    to detect unexpected cases that behaved differently when the sysctl
    kernel.sysctl_writes_strict != 1.
    
    [ original ]
        root@localhost:~# make test_num
        == Testing sysctl behavior against /proc/sys/kernel/domainname ==
        Writing test file ... ok
        Checking sysctl is not set to test value ... ok
        Writing sysctl from shell ... ok
        Resetting sysctl to original value ... ok
        Writing entire sysctl in single write ... ok
        Writing middle of sysctl after synchronized seek ... FAIL
        Writing beyond end of sysctl ... FAIL
        Writing sysctl with multiple long writes ... FAIL
        Writing entire sysctl in short writes ... FAIL
        Writing middle of sysctl after unsynchronized seek ... ok
        Checking sysctl maxlen is at least 65 ... ok
        Checking sysctl keeps original string on overflow append ... FAIL
        Checking sysctl stays NULL terminated on write ... ok
        Checking sysctl stays NULL terminated on overwrite ... ok
        make: *** [test_num] Error 1
        root@localhost:~# make test_string
        == Testing sysctl behavior against /proc/sys/vm/swappiness ==
        Writing test file ... ok
        Checking sysctl is not set to test value ... ok
        Writing sysctl from shell ... ok
        Resetting sysctl to original value ... ok
        Writing entire sysctl in single write ... ok
        Writing middle of sysctl after synchronized seek ... FAIL
        Writing beyond end of sysctl ... FAIL
        Writing sysctl with multiple long writes ... ok
        make: *** [test_string] Error 1
    
    [ with CONFIG_PROC_SYSCTL_STRICT_WRITES ]
        root@localhost:~# make run_tests
        == Testing sysctl behavior against /proc/sys/kernel/domainname ==
        Writing test file ... ok
        Checking sysctl is not set to test value ... ok
        Writing sysctl from shell ... ok
        Resetting sysctl to original value ... ok
        Writing entire sysctl in single write ... ok
        Writing middle of sysctl after synchronized seek ... ok
        Writing beyond end of sysctl ... ok
        Writing sysctl with multiple long writes ... ok
        Writing entire sysctl in short writes ... ok
        Writing middle of sysctl after unsynchronized seek ... ok
        Checking sysctl maxlen is at least 65 ... ok
        Checking sysctl keeps original string on overflow append ... ok
        Checking sysctl stays NULL terminated on write ... ok
        Checking sysctl stays NULL terminated on overwrite ... ok
        == Testing sysctl behavior against /proc/sys/vm/swappiness ==
        Writing test file ... ok
        Checking sysctl is not set to test value ... ok
        Writing sysctl from shell ... ok
        Resetting sysctl to original value ... ok
        Writing entire sysctl in single write ... ok
        Writing middle of sysctl after synchronized seek ... ok
        Writing beyond end of sysctl ... ok
        Writing sysctl with multiple long writes ... ok
    Signed-off-by: default avatarKees Cook <keescook@chromium.org>
    Cc: Randy Dunlap <rdunlap@infradead.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    24fe831c
Makefile 472 Bytes