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| author | Kees Cook <keescook@chromium.org> | 2020-06-25 13:37:01 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-06-29 18:41:39 +0200 |
| commit | 464e86b4abadfc490f426954b431e2ec6a9d7bd2 (patch) | |
| tree | 0f383cba11e1e20a74cea7c8652cfa1309d8128d /drivers/misc/lkdtm/bugs.c | |
| parent | 4afc339ef0d259d415993d3d96f707a92489d91e (diff) | |
| download | linux-stable-464e86b4abadfc490f426954b431e2ec6a9d7bd2.tar.gz linux-stable-464e86b4abadfc490f426954b431e2ec6a9d7bd2.tar.bz2 linux-stable-464e86b4abadfc490f426954b431e2ec6a9d7bd2.zip | |
lkdtm: Avoid more compiler optimizations for bad writes
It seems at least Clang is able to throw away writes it knows are
destined for read-only memory, which makes things like the WRITE_RO test
fail, as the write gets elided. Instead, force the variable to be
volatile, and make similar changes through-out other tests in an effort
to avoid needing to repeat fixing these kinds of problems. Also includes
pr_err() calls in failure paths so that kernel logs are more clear in
the failure case.
Reported-by: Prasad Sodagudi <psodagud@codeaurora.org>
Suggested-by: Sami Tolvanen <samitolvanen@google.com>
Fixes: 9ae113ce5faf ("lkdtm: add tests for additional page permissions")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200625203704.317097-2-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc/lkdtm/bugs.c')
| -rw-r--r-- | drivers/misc/lkdtm/bugs.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 736675f0a246..08c70281c380 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -118,9 +118,8 @@ noinline void lkdtm_CORRUPT_STACK(void) /* Use default char array length that triggers stack protection. */ char data[8] __aligned(sizeof(void *)); - __lkdtm_CORRUPT_STACK(&data); - - pr_info("Corrupted stack containing char array ...\n"); + pr_info("Corrupting stack containing char array ...\n"); + __lkdtm_CORRUPT_STACK((void *)&data); } /* Same as above but will only get a canary with -fstack-protector-strong */ @@ -131,9 +130,8 @@ noinline void lkdtm_CORRUPT_STACK_STRONG(void) unsigned long *ptr; } data __aligned(sizeof(void *)); - __lkdtm_CORRUPT_STACK(&data); - - pr_info("Corrupted stack containing union ...\n"); + pr_info("Corrupting stack containing union ...\n"); + __lkdtm_CORRUPT_STACK((void *)&data); } void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void) @@ -248,6 +246,7 @@ void lkdtm_ARRAY_BOUNDS(void) kfree(not_checked); kfree(checked); + pr_err("FAIL: survived array bounds overflow!\n"); } void lkdtm_CORRUPT_LIST_ADD(void) |