linux/tools/testing/selftests/sysctl/common_tests
Kees Cook 24fe831c17 tools/testing/selftests/sysctl: validate sysctl_writes_strict
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: Kees Cook <keescook@chromium.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:13 -07:00

110 lines
1.8 KiB
Bash

#!/bin/sh
TEST_FILE=$(mktemp)
echo "== Testing sysctl behavior against ${TARGET} =="
set_orig()
{
echo "${ORIG}" > "${TARGET}"
}
set_test()
{
echo "${TEST_STR}" > "${TARGET}"
}
verify()
{
local seen
seen=$(cat "$1")
if [ "${seen}" != "${TEST_STR}" ]; then
return 1
fi
return 0
}
trap 'set_orig; rm -f "${TEST_FILE}"' EXIT
rc=0
echo -n "Writing test file ... "
echo "${TEST_STR}" > "${TEST_FILE}"
if ! verify "${TEST_FILE}"; then
echo "FAIL" >&2
exit 1
else
echo "ok"
fi
echo -n "Checking sysctl is not set to test value ... "
if verify "${TARGET}"; then
echo "FAIL" >&2
exit 1
else
echo "ok"
fi
echo -n "Writing sysctl from shell ... "
set_test
if ! verify "${TARGET}"; then
echo "FAIL" >&2
exit 1
else
echo "ok"
fi
echo -n "Resetting sysctl to original value ... "
set_orig
if verify "${TARGET}"; then
echo "FAIL" >&2
exit 1
else
echo "ok"
fi
# Now that we've validated the sanity of "set_test" and "set_orig",
# we can use those functions to set starting states before running
# specific behavioral tests.
echo -n "Writing entire sysctl in single write ... "
set_orig
dd if="${TEST_FILE}" of="${TARGET}" bs=4096 2>/dev/null
if ! verify "${TARGET}"; then
echo "FAIL" >&2
rc=1
else
echo "ok"
fi
echo -n "Writing middle of sysctl after synchronized seek ... "
set_test
dd if="${TEST_FILE}" of="${TARGET}" bs=1 seek=1 skip=1 2>/dev/null
if ! verify "${TARGET}"; then
echo "FAIL" >&2
rc=1
else
echo "ok"
fi
echo -n "Writing beyond end of sysctl ... "
set_orig
dd if="${TEST_FILE}" of="${TARGET}" bs=20 seek=2 2>/dev/null
if verify "${TARGET}"; then
echo "FAIL" >&2
rc=1
else
echo "ok"
fi
echo -n "Writing sysctl with multiple long writes ... "
set_orig
(perl -e 'print "A" x 50;'; echo "${TEST_STR}") | \
dd of="${TARGET}" bs=50 2>/dev/null
if verify "${TARGET}"; then
echo "FAIL" >&2
rc=1
else
echo "ok"
fi