Currently in validate_extra_context() we assert both that the extra data
pointed to by the EXTRA_CONTEXT is 16 byte aligned and that it immediately
follows the struct _aarch64_ctx providing the terminator for the linked
list of contexts in the signal frame. Since struct _aarch64_ctx is an 8
byte structure which must be 16 byte aligned these cannot both be true. As
documented in sigcontext.h and implemented by the kernel the extra data
should be at the next 16 byte aligned address after the terminator so fix
the validation to match.
Signed-off-by: Mark Brown <broonie(a)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 b2cce9afaaf3..0b3c9b4b1d39 100644
--- a/tools/testing/selftests/arm64/signal/testcases/testcases.c
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c
@@ -42,7 +42,7 @@ bool validate_extra_context(struct extra_context *extra, char **err)
*err = "Extra DATAP misaligned";
else if (extra->size & 0x0fUL)
*err = "Extra SIZE misaligned";
- else if (extra->datap != (uint64_t)term + sizeof(*term))
+ else if (extra->datap != (uint64_t)term + 0x10UL)
*err = "Extra DATAP misplaced (not contiguous)";
if (*err)
return false;
--
2.30.2
In handle_input_signal_copyctx() we use ASSERT_GOOD_CONTEXT() to validate
that the context we are saving meets expectations however we do this on
the saved copy rather than on the actual signal context passed in. This
breaks validation of EXTRA_CONTEXT since we attempt to validate the ABI
requirement that the additional space supplied is immediately after the
termination record in the standard context which will not be the case
after it has been copied to another location.
Fix this by doing the validation before we copy. Note that nothing actually
looks inside the EXTRA_CONTEXT at present.
Signed-off-by: Mark Brown <broonie(a)kernel.org>
---
.../testing/selftests/arm64/signal/test_signals_utils.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.c b/tools/testing/selftests/arm64/signal/test_signals_utils.c
index b588d10afd5b..a54dc1b6f35c 100644
--- a/tools/testing/selftests/arm64/signal/test_signals_utils.c
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.c
@@ -165,12 +165,15 @@ static bool handle_signal_ok(struct tdescr *td,
}
static bool handle_signal_copyctx(struct tdescr *td,
- siginfo_t *si, void *uc)
+ siginfo_t *si, void *uc_in)
{
+ ucontext_t *uc = uc_in;
+
+ ASSERT_GOOD_CONTEXT(uc);
+
/* Mangling PC to avoid loops on original BRK instr */
- ((ucontext_t *)uc)->uc_mcontext.pc += 4;
+ uc->uc_mcontext.pc += 4;
memcpy(td->live_uc, uc, td->live_sz);
- ASSERT_GOOD_CONTEXT(td->live_uc);
td->live_uc_valid = 1;
fprintf(stderr,
"GOOD CONTEXT grabbed from sig_copyctx handler\n");
--
2.30.2
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 terminator 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(a)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