From: Felix Maurer fmaurer@redhat.com
commit 61d06f01f9710b327a53492e5add9f972eb909b3 upstream.
bpf_msg_push_data may return a non-zero value to indicate an error. The return value should be checked to prevent undetected errors.
To indicate an error, the BPF programs now perform a different action than their intended one to make the userspace test program notice the error, i.e., the programs supposed to pass/redirect drop, the program supposed to drop passes.
Fixes: 84fbfe026acaa ("bpf: test_sockmap add options to use msg_push_data") Signed-off-by: Felix Maurer fmaurer@redhat.com Signed-off-by: Alexei Starovoitov ast@kernel.org Acked-by: John Fastabend john.fastabend@gmail.com Link: https://lore.kernel.org/bpf/89f767bb44005d6b4dd1f42038c438f76b3ebfad.1644601... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/bpf/progs/test_sockmap_kern.h | 26 ++++++++++++------ 1 file changed, 18 insertions(+), 8 deletions(-)
--- a/tools/testing/selftests/bpf/progs/test_sockmap_kern.h +++ b/tools/testing/selftests/bpf/progs/test_sockmap_kern.h @@ -235,7 +235,7 @@ SEC("sk_msg1") int bpf_prog4(struct sk_msg_md *msg) { int *bytes, zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5; - int *start, *end, *start_push, *end_push, *start_pop, *pop; + int *start, *end, *start_push, *end_push, *start_pop, *pop, err = 0;
bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero); if (bytes) @@ -249,8 +249,11 @@ int bpf_prog4(struct sk_msg_md *msg) bpf_msg_pull_data(msg, *start, *end, 0); start_push = bpf_map_lookup_elem(&sock_bytes, &two); end_push = bpf_map_lookup_elem(&sock_bytes, &three); - if (start_push && end_push) - bpf_msg_push_data(msg, *start_push, *end_push, 0); + if (start_push && end_push) { + err = bpf_msg_push_data(msg, *start_push, *end_push, 0); + if (err) + return SK_DROP; + } start_pop = bpf_map_lookup_elem(&sock_bytes, &four); pop = bpf_map_lookup_elem(&sock_bytes, &five); if (start_pop && pop) @@ -263,6 +266,7 @@ int bpf_prog6(struct sk_msg_md *msg) { int zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5, key = 0; int *bytes, *start, *end, *start_push, *end_push, *start_pop, *pop, *f; + int err = 0; __u64 flags = 0;
bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero); @@ -279,8 +283,11 @@ int bpf_prog6(struct sk_msg_md *msg)
start_push = bpf_map_lookup_elem(&sock_bytes, &two); end_push = bpf_map_lookup_elem(&sock_bytes, &three); - if (start_push && end_push) - bpf_msg_push_data(msg, *start_push, *end_push, 0); + if (start_push && end_push) { + err = bpf_msg_push_data(msg, *start_push, *end_push, 0); + if (err) + return SK_DROP; + }
start_pop = bpf_map_lookup_elem(&sock_bytes, &four); pop = bpf_map_lookup_elem(&sock_bytes, &five); @@ -338,7 +345,7 @@ SEC("sk_msg5") int bpf_prog10(struct sk_msg_md *msg) { int *bytes, *start, *end, *start_push, *end_push, *start_pop, *pop; - int zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5; + int zero = 0, one = 1, two = 2, three = 3, four = 4, five = 5, err = 0;
bytes = bpf_map_lookup_elem(&sock_apply_bytes, &zero); if (bytes) @@ -352,8 +359,11 @@ int bpf_prog10(struct sk_msg_md *msg) bpf_msg_pull_data(msg, *start, *end, 0); start_push = bpf_map_lookup_elem(&sock_bytes, &two); end_push = bpf_map_lookup_elem(&sock_bytes, &three); - if (start_push && end_push) - bpf_msg_push_data(msg, *start_push, *end_push, 0); + if (start_push && end_push) { + err = bpf_msg_push_data(msg, *start_push, *end_push, 0); + if (err) + return SK_PASS; + } start_pop = bpf_map_lookup_elem(&sock_bytes, &four); pop = bpf_map_lookup_elem(&sock_bytes, &five); if (start_pop && pop)