On Mon, Sep 02, 2019 at 12:29:30pm +0100, Cristian Marussi wrote:
> Add a simple fake_sigreturn testcase which builds a ucontext_t with
> an anomalous additional fpsimd_context and place it onto the stack.
> Expects a SIGSEGV on test PASS.
>
> Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
> ---
> v3 --> v4
> - fix commit
> - missing include
> - using new get_starting_head() helper
> - added test description
> ---
> .../fake_sigreturn_duplicated_fpsimd.c | 52 +++++++++++++++++++
> 1 file changed, 52 insertions(+)
> create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
>
> diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
> new file mode 100644
> index 000000000000..c7122c44f53f
> --- /dev/null
> +++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_duplicated_fpsimd.c
> @@ -0,0 +1,52 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 ARM Limited
> + *
> + * Place a fake sigframe on the stack including an additional FPSIMD
> + * record: on sigreturn Kernel must spot this attempt and the test
> + * case is expected to be terminated via SEGV.
> + */
> +
> +#include <signal.h>
> +#include <ucontext.h>
> +
> +#include "test_signals_utils.h"
> +#include "testcases.h"
> +
> +struct fake_sigframe sf;
> +
> +static int fake_sigreturn_duplicated_fpsimd_run(struct tdescr *td,
> + siginfo_t *si, ucontext_t *uc)
> +{
> + size_t resv_sz, need_sz;
> + struct _aarch64_ctx *shead = GET_SF_RESV_HEAD(sf), *head;
> +
> + /* just to fill the ucontext_t with something real */
> + if (!get_current_context(td, &sf.uc))
> + return 1;
> +
> + resv_sz = GET_SF_RESV_SIZE(sf);
> + need_sz = HDR_SZ + sizeof(struct fpsimd_context);
Nit: Maybe write this sum in the same order as the records we're going
o append, i.e.:
need_sz = sizeof(struct fpsimd_context) + HDR_SZ; /* for terminator */
Also, maybe fail this test if there is no fpsimd_context in the initial
frame from get_current_context(): that would be a kernel bug, but we
wouldn't be giving fake_sigreturn() duplicate fpsimd_contexts in that
case -- so this test wouldn't test the thing it's supposed to test.
> +
> + head = get_starting_head(shead, need_sz, resv_sz, NULL);
> + if (head) {
> + /* Add a spurios fpsimd_context */
> + head->magic = FPSIMD_MAGIC;
> + head->size = sizeof(struct fpsimd_context);
> + /* and terminate */
> + write_terminator_record(GET_RESV_NEXT_HEAD(head));
> +
> + ASSERT_BAD_CONTEXT(&sf.uc);
> + fake_sigreturn(&sf, sizeof(sf), 0);
> + }
> +
> + return 1;
[...]
Cheers
---Dave
