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Miller" , Jakub Kicinski , Simon Horman , Jonathan Corbet , Shuah Khan , Randy Dunlap , Stanislav Fomichev Cc: Michal Luczaj , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, Sashiko X-Mailer: b4 0.15.2 Among tracing progs, allow only iter/sockmap to update sockmaps and sockhashes. Previously, any BPF_TRACE_ITER program could perform these updates, which caused locking issues in specific scenarios [1][2][3]. This tightening is part of the broader effort to lock down the BPF API [4]. [1]: commit 4d328dd69538 ("bpf, sockmap: Fix af_unix iter deadlock") [2]: commit 64c2f93fc325 ("bpf, sockmap: Take state lock for af_unix iter") [3]: https://msgid.link/87echn2fhd.fsf@cloudflare.com [4]: https://msgid.link/akRZ_e7DJh2aP-2i@john-p8 Reported-by: Sashiko Closes: https://msgid.link/20260626205814.BAC3C1F000E9@smtp.kernel.org Suggested-by: Jakub Sitnicki Signed-off-by: Michal Luczaj --- I was tempted to define BTF_ID_LIST_SINGLE(bpf_iter_sockmap_id, func, bpf_iter_sockmap) and just compare against env->prog->aux->attach_btf_id, but a single line BTF_ID_LIST_SINGLE quickly turned into a 6-line ifdef-CONFIG_NET-fery, so I've sticked with strcmp(). --- kernel/bpf/verifier.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 09a44723bb2e..e784e4a1e5f2 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10543,6 +10543,7 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) { enum bpf_attach_type eatype = env->prog->expected_attach_type; enum bpf_prog_type type = resolve_prog_type(env->prog); + const char *afname = env->prog->aux->attach_func_name; if (func_id != BPF_FUNC_map_update_elem && func_id != BPF_FUNC_map_delete_elem) @@ -10553,7 +10554,8 @@ static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id) */ switch (type) { case BPF_PROG_TYPE_TRACING: - if (eatype == BPF_TRACE_ITER) + if (eatype == BPF_TRACE_ITER && + !strcmp(afname + strlen(BPF_ITER_FUNC_PREFIX), "sockmap")) return true; break; case BPF_PROG_TYPE_SOCK_OPS: -- 2.56.0