The patch titled
Subject: tools/testing/selftests/sysctl/sysctl.sh: add tests for >32-bit values written to 32-bit integers
has been added to the -mm tree. Its filename is
test_sysctl-add-tests-for-32-bit-values-written-to-32-bit-integers.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/test_sysctl-add-tests-for-32-bit-values-written-to-32-bit-integers.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/test_sysctl-add-tests-for-32-bit-values-written-to-32-bit-integers.patch
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------------------------------------------------------
From: Zev Weiss <zev@xxxxxxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxx
Signed-off-by: Zev Weiss <zev@xxxxxxxxxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Cc: Iurii Zaikin <yzaikin@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/tools/testing/selftests/sysctl/sysctl.sh~test_sysctl-add-tests-for-32-bit-values-written-to-32-bit-integers
+++ a/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
}
_
Patches currently in -mm which might be from zev@xxxxxxxxxxxxxxxxx are
test_sysctl-add-tests-for-32-bit-values-written-to-32-bit-integers.patch
kernel-sysctlc-add-missing-range-check-in-do_proc_dointvec_minmax_conv.patch
kernel-sysctlc-define-minmax-conv-functions-in-terms-of-non-minmax-versions.patch
