From 01c0514ec8226386ce8367dcd8814f86224caaeb Mon Sep 17 00:00:00 2001 From: Alexander Popov Date: Fri, 3 Jan 2020 02:49:07 +0300 Subject: lkdtm/stackleak: Make the test more verbose Make the stack erasing test more verbose about the errors that it can detect. Signed-off-by: Alexander Popov Cc: Kees Cook Link: https://lore.kernel.org/r/20200102234907.585508-1-alex.popov@linux.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/lkdtm/stackleak.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) (limited to 'drivers/misc/lkdtm/stackleak.c') diff --git a/drivers/misc/lkdtm/stackleak.c b/drivers/misc/lkdtm/stackleak.c index d5a084475abc..d1a5c0705be3 100644 --- a/drivers/misc/lkdtm/stackleak.c +++ b/drivers/misc/lkdtm/stackleak.c @@ -16,6 +16,7 @@ void lkdtm_STACKLEAK_ERASING(void) unsigned long *sp, left, found, i; const unsigned long check_depth = STACKLEAK_SEARCH_DEPTH / sizeof(unsigned long); + bool test_failed = false; /* * For the details about the alignment of the poison values, see @@ -34,7 +35,8 @@ void lkdtm_STACKLEAK_ERASING(void) left--; } else { pr_err("FAIL: not enough stack space for the test\n"); - return; + test_failed = true; + goto end; } pr_info("checking unused part of the thread stack (%lu bytes)...\n", @@ -52,22 +54,29 @@ void lkdtm_STACKLEAK_ERASING(void) } if (found <= check_depth) { - pr_err("FAIL: thread stack is not erased (checked %lu bytes)\n", + pr_err("FAIL: the erased part is not found (checked %lu bytes)\n", i * sizeof(unsigned long)); - return; + test_failed = true; + goto end; } - pr_info("first %lu bytes are unpoisoned\n", + pr_info("the erased part begins after %lu not poisoned bytes\n", (i - found) * sizeof(unsigned long)); /* The rest of thread stack should be erased */ for (; i < left; i++) { if (*(sp - i) != STACKLEAK_POISON) { - pr_err("FAIL: thread stack is NOT properly erased\n"); - return; + pr_err("FAIL: bad value number %lu in the erased part: 0x%lx\n", + i, *(sp - i)); + test_failed = true; } } - pr_info("OK: the rest of the thread stack is properly erased\n"); - return; +end: + if (test_failed) { + pr_err("FAIL: the thread stack is NOT properly erased\n"); + dump_stack(); + } else { + pr_info("OK: the rest of the thread stack is properly erased\n"); + } } -- cgit v1.2.3