On Thu, Jun 13, 2019 at 12:13:25PM +0100, Cristian Marussi wrote:
Added a simple mangle testcase which messes with the ucontext_t from within the sig_handler, trying to badly modify and misalign the SP. Expects SIGBUS on test PASS.
Signed-off-by: Cristian Marussi cristian.marussi@arm.com
.../arm64/signal/testcases/.gitignore | 1 + .../signal/testcases/mangle_sp_misaligned.c | 24 +++++++++++++++++++ 2 files changed, 25 insertions(+) create mode 100644 tools/testing/selftests/arm64/signal/testcases/.gitignore create mode 100644 tools/testing/selftests/arm64/signal/testcases/mangle_sp_misaligned.c
diff --git a/tools/testing/selftests/arm64/signal/testcases/.gitignore b/tools/testing/selftests/arm64/signal/testcases/.gitignore new file mode 100644 index 000000000000..7f7414d241f2 --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/.gitignore @@ -0,0 +1 @@ +mangle_sp_misaligned diff --git a/tools/testing/selftests/arm64/signal/testcases/mangle_sp_misaligned.c b/tools/testing/selftests/arm64/signal/testcases/mangle_sp_misaligned.c new file mode 100644 index 000000000000..41bd27312e54 --- /dev/null +++ b/tools/testing/selftests/arm64/signal/testcases/mangle_sp_misaligned.c @@ -0,0 +1,24 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2019 ARM Limited */
+#include "test_signals_utils.h" +#include "testcases.h"
+static int mangle_misaligned_sp_run(struct tdescr *td, siginfo_t *si,
ucontext_t *uc)+{
- ASSERT_GOOD_CONTEXT(uc);
- uc->uc_mcontext.sp += 3;
What are we testing here?
It is archietcturally permitted (if unusual) to have a misaligned sp in userspace.
So are we just getting a SIGBUS after the sigreturn, when the thread tries to dereference sp? If so, we aren't really testing anything about sigreturn here -- I don't see any check in the kernel when restoring sp in sigreturn.
Even if there were no SIGBUS, the thread stack is now corrupt (due to wrong sp), so the interrupted code is unlikely to continue running successfully.
Am I missing something?
[...]
Cheers ---Dave