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| author | Paul Chaignon <paul.chaignon@gmail.com> | 2025-08-01 11:49:44 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-08-01 14:47:39 -0700 |
| commit | d8d2d9d12f141302aaec3ff9a3a8cbed4ac0546c (patch) | |
| tree | 34f31c251bb0a900926a740a3ec5f811a207f1b6 | |
| parent | f914876eec9e72ae94b5cee81a9dc7935c255b2f (diff) | |
selftests/bpf: Test for unaligned flow_dissector ctx access
This patch adds tests for two context fields where unaligned accesses
were not properly rejected.
Note the new macro is similar to the existing narrow_load macro, but we
need a different description and access offset. Combining the two
macros into one is probably doable but I don't think it would help
readability.
vmlinux.h is included in place of bpf.h so we have the definition of
struct bpf_nf_ctx.
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/bf014046ddcf41677fb8b98d150c14027e9fddba.1754039605.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_ctx.c | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_ctx.c b/tools/testing/selftests/bpf/progs/verifier_ctx.c index 0450840c92d9..424463094760 100644 --- a/tools/testing/selftests/bpf/progs/verifier_ctx.c +++ b/tools/testing/selftests/bpf/progs/verifier_ctx.c @@ -1,10 +1,12 @@ // SPDX-License-Identifier: GPL-2.0 /* Converted from tools/testing/selftests/bpf/verifier/ctx.c */ -#include <linux/bpf.h> +#include "vmlinux.h" #include <bpf/bpf_helpers.h> #include "bpf_misc.h" +#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER)) + SEC("tc") __description("context stores via BPF_ATOMIC") __failure __msg("BPF_ATOMIC stores into R1 ctx is not allowed") @@ -243,4 +245,23 @@ narrow_load("sockops", bpf_sock_ops, skb_data); narrow_load("sockops", bpf_sock_ops, skb_data_end); narrow_load("sockops", bpf_sock_ops, skb_hwtstamp); +#define unaligned_access(type, ctx, field) \ + SEC(type) \ + __description("unaligned access on field " #field " of " #ctx) \ + __failure __msg("invalid bpf_context access") \ + __naked void unaligned_ctx_access_##ctx##field(void) \ + { \ + asm volatile (" \ + r1 = *(u%[size] *)(r1 + %[off]); \ + r0 = 0; \ + exit;" \ + : \ + : __imm_const(size, sizeof_field(struct ctx, field) * 8), \ + __imm_const(off, offsetof(struct ctx, field) + 1) \ + : __clobber_all); \ + } + +unaligned_access("flow_dissector", __sk_buff, data); +unaligned_access("netfilter", bpf_nf_ctx, skb); + char _license[] SEC("license") = "GPL"; |