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lkdtm/stackleak: Make the test more verbose

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Make the stack erasing test more verbose about the errors that it
can detect.

Signed-off-by: Alexander Popov <alex.popov@linux.com>
Cc: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200102234907.585508-1-alex.popov@linux.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Popov 2020-01-03 02:49:07 +03:00 committed by Greg Kroah-Hartman
parent ff5cd9accb
commit 01c0514ec8
1 changed files with 17 additions and 8 deletions
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25
drivers/misc/lkdtm/stackleak.c
View File

@ -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");
}
}