From: Andrii Nakryiko <andrii@kernel.org>
To: <bpf@vger.kernel.org>, <ast@kernel.org>, <daniel@iogearbox.net>
Cc: <andrii@kernel.org>, <kernel-team@fb.com>
Subject: [PATCH bpf-next 09/13] selftests/bpf: prevent misaligned memory access in get_stack_raw_tp test
Date: Tue, 23 Nov 2021 16:23:21 -0800 [thread overview]
Message-ID: <20211124002325.1737739-10-andrii@kernel.org> (raw)
In-Reply-To: <20211124002325.1737739-1-andrii@kernel.org>
Perfbuf doesn't guarantee 8-byte alignment of the data like BPF ringbuf
does, so struct get_stack_trace_t can arrive not properly aligned for
subsequent u64 accesses. Easiest fix is to just copy data locally.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
.../selftests/bpf/prog_tests/get_stack_raw_tp.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c
index 4184c399d4c6..977ab433a946 100644
--- a/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c
+++ b/tools/testing/selftests/bpf/prog_tests/get_stack_raw_tp.c
@@ -24,13 +24,19 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size)
{
bool good_kern_stack = false, good_user_stack = false;
const char *nonjit_func = "___bpf_prog_run";
- struct get_stack_trace_t *e = data;
+ /* perfbuf-submitted data is 4-byte aligned, but we need 8-byte
+ * alignment, so copy data into a local variable, for simplicity
+ */
+ struct get_stack_trace_t e;
int i, num_stack;
static __u64 cnt;
struct ksym *ks;
cnt++;
+ memset(&e, 0, sizeof(e));
+ memcpy(&e, data, size <= sizeof(e) ? size : sizeof(e));
+
if (size < sizeof(struct get_stack_trace_t)) {
__u64 *raw_data = data;
bool found = false;
@@ -57,19 +63,19 @@ static void get_stack_print_output(void *ctx, int cpu, void *data, __u32 size)
good_user_stack = true;
}
} else {
- num_stack = e->kern_stack_size / sizeof(__u64);
+ num_stack = e.kern_stack_size / sizeof(__u64);
if (env.jit_enabled) {
good_kern_stack = num_stack > 0;
} else {
for (i = 0; i < num_stack; i++) {
- ks = ksym_search(e->kern_stack[i]);
+ ks = ksym_search(e.kern_stack[i]);
if (ks && (strcmp(ks->name, nonjit_func) == 0)) {
good_kern_stack = true;
break;
}
}
}
- if (e->user_stack_size > 0 && e->user_stack_buildid_size > 0)
+ if (e.user_stack_size > 0 && e.user_stack_buildid_size > 0)
good_user_stack = true;
}
--
2.30.2
next prev parent reply other threads:[~2021-11-24 0:23 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 0:23 [PATCH bpf-next 00/13] Fix sanitizer-reported libbpf and selftest issues Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 01/13] tools/resolve_btf_ids: close ELF file on error Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 02/13] libbpf: fix potential misaligned memory access in btf_ext__new() Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 03/13] libbpf: prevent UBSan from complaining about integer overflow Andrii Nakryiko
2021-11-25 22:21 ` Daniel Borkmann
2021-11-25 23:19 ` Daniel Borkmann
2021-11-26 1:23 ` Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 04/13] libbpf: don't call libc APIs with NULL pointers Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 05/13] libbpf: fix glob_syms memory leak in bpf_linker Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 06/13] libbpf: fix using invalidated memory " Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 07/13] selftests/bpf: fix UBSan complaint about signed __int128 overflow Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 08/13] selftests/bpf: fix possible NULL passed to memcpy() with zero size Andrii Nakryiko
2021-11-24 0:23 ` Andrii Nakryiko [this message]
2021-11-24 0:23 ` [PATCH bpf-next 10/13] selftests/bpf: fix misaligned memory access in queue_stack_map test Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 11/13] selftests/bpf: prevent out-of-bounds stack access in test_bpffs Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 12/13] selftests/bpf: fix misaligned memory accesses in xdp_bonding test Andrii Nakryiko
2021-11-24 0:23 ` [PATCH bpf-next 13/13] selftests/bpf: fix misaligned accesses in xdp and xdp_bpf2bpf tests Andrii Nakryiko
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