[PATCH AUTOSEL 5.15 11/26] kselftest/arm64: Fix validatation termination record after EXTRA_CONTEXT

[Sasha Levin]

From: Mark Brown <broonie@xxxxxxxxxx>

[ Upstream commit 5c152c2f66f9368394b89ac90dc7483476ef7b88 ]

When arm64 signal context data overflows the base struct sigcontext it gets
placed in an extra buffer pointed to by a record of type EXTRA_CONTEXT in
the base struct sigcontext which is required to be the last record in the
base struct sigframe. The current validation code attempts to check this
by using GET_RESV_NEXT_HEAD() to step forward from the current record to
the next but that is a macro which assumes it is being provided with a
struct _aarch64_ctx and uses the size there to skip forward to the next
record. Instead validate_extra_context() passes it a struct extra_context
which has a separate size field. This compiles but results in us trying
to validate a termination record in completely the wrong place, at best
failing validation and at worst just segfaulting. Fix this by passing
the struct _aarch64_ctx we meant to into the macro.

Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220829160703.874492-4-broonie@xxxxxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 tools/testing/selftests/arm64/signal/testcases/testcases.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.c b/tools/testing/selftests/arm64/signal/testcases/testcases.c
index 8c2a57fc2f9c..341b3d5200bd 100644
--- a/tools/testing/selftests/arm64/signal/testcases/testcases.c
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c
@@ -33,7 +33,7 @@ bool validate_extra_context(struct extra_context *extra, char **err)
 		return false;
 
 	fprintf(stderr, "Validating EXTRA...\n");
-	term = GET_RESV_NEXT_HEAD(extra);
+	term = GET_RESV_NEXT_HEAD(&extra->head);
 	if (!term || term->magic || term->size) {
 		*err = "Missing terminator after EXTRA context";
 		return false;
-- 
2.35.1