[PATCH v2 03/10] kselftest/arm64: Fix validatation termination record after EXTRA_CONTEXT

From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Shuah Khan <shuah@kernel.org>,
	Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kselftest@vger.kernel.org, Mark Brown <broonie@kernel.org>
Subject: [PATCH v2 03/10] kselftest/arm64: Fix validatation termination record after EXTRA_CONTEXT
Date: Mon, 29 Aug 2022 17:06:56 +0100	[thread overview]
Message-ID: <20220829160703.874492-4-broonie@kernel.org> (raw)
In-Reply-To: <20220829160703.874492-1-broonie@kernel.org>

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@kernel.org>
---
 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 84c36bee4d82..d98828cb542b 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;
-- 
2.30.2

