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authorKees Cook <keescook@chromium.org>2014-06-06 14:37:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-06 16:08:13 -0700
commit24fe831c17ab8149413874f2fd4e5c8a41fcd294 (patch)
tree8dfd55de2ff614c628b80e2182ad932e87a83aeb /tools/testing/selftests/sysctl
parentf4aacea2f5d1a5f7e3154e967d70cf3f711bcd61 (diff)
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>
Diffstat (limited to 'tools/testing/selftests/sysctl')
-rw-r--r--tools/testing/selftests/sysctl/Makefile19
-rw-r--r--tools/testing/selftests/sysctl/common_tests109
-rw-r--r--tools/testing/selftests/sysctl/run_numerictests10
-rw-r--r--tools/testing/selftests/sysctl/run_stringtests77
4 files changed, 215 insertions, 0 deletions
diff --git a/tools/testing/selftests/sysctl/Makefile b/tools/testing/selftests/sysctl/Makefile
new file mode 100644
index 000000000000..0a92adaf0865
--- /dev/null
+++ b/tools/testing/selftests/sysctl/Makefile
@@ -0,0 +1,19 @@
+# Makefile for sysctl selftests.
+# Expects kernel.sysctl_writes_strict=1.
+
+# No binaries, but make sure arg-less "make" doesn't trigger "run_tests".
+all:
+
+# Allow specific tests to be selected.
+test_num:
+ @/bin/sh ./run_numerictests
+
+test_string:
+ @/bin/sh ./run_stringtests
+
+run_tests: all test_num test_string
+
+# Nothing to clean up.
+clean:
+
+.PHONY: all run_tests clean test_num test_string
diff --git a/tools/testing/selftests/sysctl/common_tests b/tools/testing/selftests/sysctl/common_tests
new file mode 100644
index 000000000000..17d534b1b7b4
--- /dev/null
+++ b/tools/testing/selftests/sysctl/common_tests
@@ -0,0 +1,109 @@
+#!/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
diff --git a/tools/testing/selftests/sysctl/run_numerictests b/tools/testing/selftests/sysctl/run_numerictests
new file mode 100644
index 000000000000..8510f93f2d14
--- /dev/null
+++ b/tools/testing/selftests/sysctl/run_numerictests
@@ -0,0 +1,10 @@
+#!/bin/sh
+
+SYSCTL="/proc/sys"
+TARGET="${SYSCTL}/vm/swappiness"
+ORIG=$(cat "${TARGET}")
+TEST_STR=$(( $ORIG + 1 ))
+
+. ./common_tests
+
+exit $rc
diff --git a/tools/testing/selftests/sysctl/run_stringtests b/tools/testing/selftests/sysctl/run_stringtests
new file mode 100644
index 000000000000..90a9293d520c
--- /dev/null
+++ b/tools/testing/selftests/sysctl/run_stringtests
@@ -0,0 +1,77 @@
+#!/bin/sh
+
+SYSCTL="/proc/sys"
+TARGET="${SYSCTL}/kernel/domainname"
+ORIG=$(cat "${TARGET}")
+TEST_STR="Testing sysctl"
+
+. ./common_tests
+
+# Only string sysctls support seeking/appending.
+MAXLEN=65
+
+echo -n "Writing entire sysctl in short writes ... "
+set_orig
+dd if="${TEST_FILE}" of="${TARGET}" bs=1 2>/dev/null
+if ! verify "${TARGET}"; then
+ echo "FAIL" >&2
+ rc=1
+else
+ echo "ok"
+fi
+
+echo -n "Writing middle of sysctl after unsynchronized seek ... "
+set_test
+dd if="${TEST_FILE}" of="${TARGET}" bs=1 seek=1 2>/dev/null
+if verify "${TARGET}"; then
+ echo "FAIL" >&2
+ rc=1
+else
+ echo "ok"
+fi
+
+echo -n "Checking sysctl maxlen is at least $MAXLEN ... "
+set_orig
+perl -e 'print "A" x ('"${MAXLEN}"'-2), "B";' | \
+ dd of="${TARGET}" bs="${MAXLEN}" 2>/dev/null
+if ! grep -q B "${TARGET}"; then
+ echo "FAIL" >&2
+ rc=1
+else
+ echo "ok"
+fi
+
+echo -n "Checking sysctl keeps original string on overflow append ... "
+set_orig
+perl -e 'print "A" x ('"${MAXLEN}"'-1), "B";' | \
+ dd of="${TARGET}" bs=$(( MAXLEN - 1 )) 2>/dev/null
+if grep -q B "${TARGET}"; then
+ echo "FAIL" >&2
+ rc=1
+else
+ echo "ok"
+fi
+
+echo -n "Checking sysctl stays NULL terminated on write ... "
+set_orig
+perl -e 'print "A" x ('"${MAXLEN}"'-1), "B";' | \
+ dd of="${TARGET}" bs="${MAXLEN}" 2>/dev/null
+if grep -q B "${TARGET}"; then
+ echo "FAIL" >&2
+ rc=1
+else
+ echo "ok"
+fi
+
+echo -n "Checking sysctl stays NULL terminated on overwrite ... "
+set_orig
+perl -e 'print "A" x ('"${MAXLEN}"'-1), "BB";' | \
+ dd of="${TARGET}" bs=$(( $MAXLEN + 1 )) 2>/dev/null
+if grep -q B "${TARGET}"; then
+ echo "FAIL" >&2
+ rc=1
+else
+ echo "ok"
+fi
+
+exit $rc