Extend the test module with a new test case (test1) that intentionally overflows a local u64 buffer to corrupt the stack canary.
Signed-off-by: Jinchao Wang <[email protected]> --- mm/kstackwatch/test.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/mm/kstackwatch/test.c b/mm/kstackwatch/test.c index 1ed98931cc51..740e3c11b3ef 100644 --- a/mm/kstackwatch/test.c +++ b/mm/kstackwatch/test.c @@ -43,6 +43,20 @@ static void test_watch_fire(void) pr_info("exit of %s\n", __func__); } +static void test_canary_overflow(void) +{ + u64 buffer[BUFFER_SIZE]; + + pr_info("entry of %s\n", __func__); + + /* intentionally overflow */ + for (int i = BUFFER_SIZE; i < BUFFER_SIZE + 10; i++) + buffer[i] = 0xdeadbeefdeadbeef; + barrier_data(buffer); + + pr_info("exit of %s\n", __func__); +} + static ssize_t test_proc_write(struct file *file, const char __user *buffer, size_t count, loff_t *pos) @@ -66,6 +80,9 @@ static ssize_t test_proc_write(struct file *file, const char __user *buffer, case 0: test_watch_fire(); break; + case 1: + test_canary_overflow(); + break; default: pr_err("Unknown test number %d\n", test_num); return -EINVAL; @@ -85,7 +102,8 @@ static ssize_t test_proc_read(struct file *file, char __user *buffer, "============ usage ==============\n" "Usage:\n" "echo test{i} > /proc/kstackwatch_test\n" - " test0 - test watch fire\n"; + " test0 - test watch fire\n" + " test1 - test canary overflow\n"; return simple_read_from_buffer(buffer, count, pos, usage, strlen(usage)); -- 2.43.0
