diff options
| author |   Paul Chaignon <paul.chaignon@gmail.com> | 2025-07-22 16:33:37 +0200 |
|---|---|---|
| committer |   Martin KaFai Lau <martin.lau@kernel.org> | 2025-07-23 19:35:56 -0700 |
| commit | ba578b87fe2beef95b37264f8a98c0b505b93de9 (patch) | |
| tree | 712d3d17bf1d7b9fe8afd37d8a0eff096d017ed2 | |
| parent | bpf: Reject narrower access to pointer ctx fields (diff) | |
| download | wireguard-linux-ba578b87fe2beef95b37264f8a98c0b505b93de9.tar.xz wireguard-linux-ba578b87fe2beef95b37264f8a98c0b505b93de9.zip | |
selftests/bpf: Test invalid narrower ctx load
This patch adds selftests to cover invalid narrower loads on the
context. These used to cause kernel warnings before the previous patch.
To trigger the warning, the load had to be aligned, to read an affected
context field (ex., skb->sk), and not starting at the beginning of the
field.
The nine new cases all fail without the previous patch.
Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://patch.msgid.link/44cd83ea9c6868079943f0a436c6efa850528cc1.1753194596.git.paul.chaignon@gmail.com
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_ctx.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_ctx.c b/tools/testing/selftests/bpf/progs/verifier_ctx.c index a83809a1dbbf..0450840c92d9 100644 --- a/tools/testing/selftests/bpf/progs/verifier_ctx.c +++ b/tools/testing/selftests/bpf/progs/verifier_ctx.c @@ -218,4 +218,29 @@ __naked void null_check_8_null_bind(void) : __clobber_all); } +#define narrow_load(type, ctx, field) \ + SEC(type) \ + __description("narrow load on field " #field " of " #ctx) \ + __failure __msg("invalid bpf_context access") \ + __naked void invalid_narrow_load##ctx##field(void) \ + { \ + asm volatile (" \ + r1 = *(u32 *)(r1 + %[off]); \ + r0 = 0; \ + exit;" \ + : \ + : __imm_const(off, offsetof(struct ctx, field) + 4) \ + : __clobber_all); \ + } + +narrow_load("cgroup/getsockopt", bpf_sockopt, sk); +narrow_load("cgroup/getsockopt", bpf_sockopt, optval); +narrow_load("cgroup/getsockopt", bpf_sockopt, optval_end); +narrow_load("tc", __sk_buff, sk); +narrow_load("cgroup/bind4", bpf_sock_addr, sk); +narrow_load("sockops", bpf_sock_ops, sk); +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); + char _license[] SEC("license") = "GPL"; |