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authorZev Weiss <zev@bewilderbeest.net>2019-03-11 23:27:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-12 10:04:00 -0700
commitfec52486682f7b3af2ffc28bcacc6e2ad6f7e1e6 (patch)
treefe71e6f77f514a186429d4313140c7b023c205fd /tools
parenta089e4fed5c5e8717f233d71bb750fbf9e1f38e0 (diff)
tools/testing/selftests/sysctl/sysctl.sh: add tests for >32-bit values written to 32-bit integers
Patch series "sysctl: fix range-checking in do_proc_dointvec_minmax_conv()", v2. After being left with an unusable system after a typo executing something like 'echo $((1<<24)) > /proc/sys/vm/max_map_count', I found that do_proc_dointvec_minmax_conv() was missing a check to ensure that the converted value actually fits in an int. The first of the following patches enhances the sysctl selftest such that it detects this problem; the second provides a minimal fix (suitable for -stable) such that the selftest passes. The third patch then performs a more thorough refactoring to eliminate the code duplication that led to the bug in the first place (maintaining the passing status of the selftest). This patch (of 3): At present this exposes a bug in do_proc_dointvec_minmax_conv() (it fails to check for values that are too wide to fit in an int). Link: http://lkml.kernel.org/r/20190207123426.9202-2-zev@bewilderbeest.net Signed-off-by: Zev Weiss <zev@bewilderbeest.net> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Iurii Zaikin <yzaikin@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'tools')
-rwxr-xr-xtools/testing/selftests/sysctl/sysctl.sh55
1 files changed, 55 insertions, 0 deletions
diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh
index 584eb8ea780a..780ce7123374 100755
--- a/tools/testing/selftests/sysctl/sysctl.sh
+++ b/tools/testing/selftests/sysctl/sysctl.sh
@@ -290,6 +290,58 @@ run_numerictests()
test_rc
}
+check_failure()
+{
+ echo -n "Testing that $1 fails as expected..."
+ reset_vals
+ TEST_STR="$1"
+ orig="$(cat $TARGET)"
+ echo -n "$TEST_STR" > $TARGET 2> /dev/null
+
+ # write should fail and $TARGET should retain its original value
+ if [ $? = 0 ] || [ "$(cat $TARGET)" != "$orig" ]; then
+ echo "FAIL" >&2
+ rc=1
+ else
+ echo "ok"
+ fi
+ test_rc
+}
+
+run_wideint_tests()
+{
+ # sysctl conversion functions receive a boolean sign and ulong
+ # magnitude; here we list the magnitudes we want to test (each of
+ # which will be tested in both positive and negative forms). Since
+ # none of these values fit in 32 bits, writing them to an int- or
+ # uint-typed sysctl should fail.
+ local magnitudes=(
+ # common boundary-condition values (zero, +1, -1, INT_MIN,
+ # and INT_MAX respectively) if truncated to lower 32 bits
+ # (potential for being falsely deemed in range)
+ 0x0000000100000000
+ 0x0000000100000001
+ 0x00000001ffffffff
+ 0x0000000180000000
+ 0x000000017fffffff
+
+ # these look like negatives, but without a leading '-' are
+ # actually large positives (should be rejected as above
+ # despite being zero/+1/-1/INT_MIN/INT_MAX in the lower 32)
+ 0xffffffff00000000
+ 0xffffffff00000001
+ 0xffffffffffffffff
+ 0xffffffff80000000
+ 0xffffffff7fffffff
+ )
+
+ for sign in '' '-'; do
+ for mag in "${magnitudes[@]}"; do
+ check_failure "${sign}${mag}"
+ done
+ done
+}
+
# Your test must accept digits 3 and 4 to use this
run_limit_digit()
{
@@ -556,6 +608,7 @@ sysctl_test_0001()
TEST_STR=$(( $ORIG + 1 ))
run_numerictests
+ run_wideint_tests
run_limit_digit
}
@@ -580,6 +633,7 @@ sysctl_test_0003()
TEST_STR=$(( $ORIG + 1 ))
run_numerictests
+ run_wideint_tests
run_limit_digit
run_limit_digit_int
}
@@ -592,6 +646,7 @@ sysctl_test_0004()
TEST_STR=$(( $ORIG + 1 ))
run_numerictests
+ run_wideint_tests
run_limit_digit
run_limit_digit_uint
}