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| author | Mark Rutland <mark.rutland@arm.com> | 2022-04-27 20:31:26 +0300 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2022-05-08 11:33:09 +0300 |
| commit | f171d695f3adfd8093272fa5776ef4a2c6b9cf08 (patch) | |
| tree | f1bca1298a914dfe84352c07ec1394c815ff067d /drivers/misc/lkdtm | |
| parent | f03a50938decaa601f02294e4d057fb0048ca9ca (diff) | |
| download | linux-f171d695f3adfd8093272fa5776ef4a2c6b9cf08.tar.xz | |
lkdtm/stackleak: check stack boundaries
The stackleak code relies upon the current SP and lowest recorded SP
falling within expected task stack boundaries.
Check this at the start of the test.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-12-mark.rutland@arm.com
Diffstat (limited to 'drivers/misc/lkdtm')
| -rw-r--r-- | drivers/misc/lkdtm/stackleak.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/drivers/misc/lkdtm/stackleak.c b/drivers/misc/lkdtm/stackleak.c index 46c60761a05e..52800583fd05 100644 --- a/drivers/misc/lkdtm/stackleak.c +++ b/drivers/misc/lkdtm/stackleak.c @@ -36,6 +36,25 @@ static void noinstr check_stackleak_irqoff(void) bool test_failed = false; /* + * Check that the current and lowest recorded stack pointer values fall + * within the expected task stack boundaries. These tests should never + * fail unless the boundaries are incorrect or we're clobbering the + * STACK_END_MAGIC, and in either casee something is seriously wrong. + */ + if (current_sp < task_stack_low || current_sp >= task_stack_high) { + pr_err("FAIL: current_stack_pointer (0x%lx) outside of task stack bounds [0x%lx..0x%lx]\n", + current_sp, task_stack_low, task_stack_high - 1); + test_failed = true; + goto out; + } + if (lowest_sp < task_stack_low || lowest_sp >= task_stack_high) { + pr_err("FAIL: current->lowest_stack (0x%lx) outside of task stack bounds [0x%lx..0x%lx]\n", + lowest_sp, task_stack_low, task_stack_high - 1); + test_failed = true; + goto out; + } + + /* * Depending on what has run prior to this test, the lowest recorded * stack pointer could be above or below the current stack pointer. * Start from the lowest of the two. @@ -87,6 +106,7 @@ static void noinstr check_stackleak_irqoff(void) poison_high - task_stack_low, task_stack_low - task_stack_base); +out: if (test_failed) { pr_err("FAIL: the thread stack is NOT properly erased!\n"); pr_expected_config(CONFIG_GCC_PLUGIN_STACKLEAK); |