From patchwork Wed Jan 24 02:21:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 13528394 X-Patchwork-Delegate: paul@paul-moore.com Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8749B17988; Wed, 24 Jan 2024 02:22:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706062972; cv=none; b=FFnOYogASsnzgSBvrI3HRVg3L838sUaVwnUvY4xa7f8Q/e9JdabbJsdA6ABtOlCMdegYaGqISX2yeh++Bp5IRc2IwcE9SQN5y5rpQSFdbr7gGUh8Woxt+dFgff1KvXmvhtIGRYlIQ5Q0ZfQ8gLwGBi/nnT3jnXu4ZCEaPmG0PKA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706062972; c=relaxed/simple; bh=pJx50yIhysHqQeApMLc3gwc/InM12I7RbYNRwzPuBkg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=gNWCRcySUXHbGA3sPvHnZjVjfyKTit61fDUDkBsAH2jy7az1ZxYyu3DdtdEuKRyDonBqeRMraMDebmR4+jIxh9miB+yqeAnc+TB9zIgxec3yoyQDDdl1eJea9HyueiI++pGRMU2L4et/u8fH3IlpbTxfAYBaFkGM18sBUbEgLD0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Oz5ML2st; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Oz5ML2st" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D5D25C433F1; Wed, 24 Jan 2024 02:22:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706062972; bh=pJx50yIhysHqQeApMLc3gwc/InM12I7RbYNRwzPuBkg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Oz5ML2stiQTZ84qLHdcXx/Xe4PRPOYjnZtodPwgnWJ8MTSpge5Kd1DaRfncTSm3wY 3cpLoTaJeRsoTN9/68BrBTDMbvyQuVJnY+NsZSvQx0z+Wvc58IEsCwiZwv4INeMYnu kFJOE5RoNowuPvnCp3yf+L4TiiZmCjq0DI4e7j8RMq0hNV47aoW47VoQDdVgmc+5x2 B/5Lo6WB5bcHml27i8DWQReSB+nLOmyTGBEA4HxuLciKfJTahP/GHzTXExtez0NAX8 MurlDs7YJGC0jpRTBtSuWXZNIBqx7mdn6ZYnaLoh4Kc1k3HAKK7KTPg3OJU4Zmya9q e83lXAXmYA5nA== From: Andrii Nakryiko To: bpf@vger.kernel.org, netdev@vger.kernel.org, paul@paul-moore.com, brauner@kernel.org Cc: torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, kernel-team@meta.com Subject: [PATCH v2 bpf-next 22/30] libbpf: further decouple feature checking logic from bpf_object Date: Tue, 23 Jan 2024 18:21:19 -0800 Message-Id: <20240124022127.2379740-23-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240124022127.2379740-1-andrii@kernel.org> References: <20240124022127.2379740-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add feat_supported() helper that accepts feature cache instead of bpf_object. This allows low-level code in bpf.c to not know or care about higher-level concept of bpf_object, yet it will be able to utilize custom feature checking in cases where BPF token might influence the outcome. Acked-by: John Fastabend Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/bpf.c | 6 +++--- tools/lib/bpf/libbpf.c | 22 +++++++++++++++------- tools/lib/bpf/libbpf_internal.h | 5 ++++- 3 files changed, 22 insertions(+), 11 deletions(-) diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c index d69137459abf..10bf11a758bf 100644 --- a/tools/lib/bpf/bpf.c +++ b/tools/lib/bpf/bpf.c @@ -146,7 +146,7 @@ int bump_rlimit_memlock(void) struct rlimit rlim; /* if kernel supports memcg-based accounting, skip bumping RLIMIT_MEMLOCK */ - if (memlock_bumped || kernel_supports(NULL, FEAT_MEMCG_ACCOUNT)) + if (memlock_bumped || feat_supported(NULL, FEAT_MEMCG_ACCOUNT)) return 0; memlock_bumped = true; @@ -181,7 +181,7 @@ int bpf_map_create(enum bpf_map_type map_type, return libbpf_err(-EINVAL); attr.map_type = map_type; - if (map_name && kernel_supports(NULL, FEAT_PROG_NAME)) + if (map_name && feat_supported(NULL, FEAT_PROG_NAME)) libbpf_strlcpy(attr.map_name, map_name, sizeof(attr.map_name)); attr.key_size = key_size; attr.value_size = value_size; @@ -265,7 +265,7 @@ int bpf_prog_load(enum bpf_prog_type prog_type, attr.kern_version = OPTS_GET(opts, kern_version, 0); attr.prog_token_fd = OPTS_GET(opts, token_fd, 0); - if (prog_name && kernel_supports(NULL, FEAT_PROG_NAME)) + if (prog_name && feat_supported(NULL, FEAT_PROG_NAME)) libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name)); attr.license = ptr_to_u64(license); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 4fc9dfd28f61..4bfc504815d5 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -5019,17 +5019,14 @@ static struct kern_feature_desc { }, }; -bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) +bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id) { struct kern_feature_desc *feat = &feature_probes[feat_id]; - struct kern_feature_cache *cache = &feature_cache; int ret; - if (obj && obj->gen_loader) - /* To generate loader program assume the latest kernel - * to avoid doing extra prog_load, map_create syscalls. - */ - return true; + /* assume global feature cache, unless custom one is provided */ + if (!cache) + cache = &feature_cache; if (READ_ONCE(cache->res[feat_id]) == FEAT_UNKNOWN) { ret = feat->probe(); @@ -5046,6 +5043,17 @@ bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) return READ_ONCE(cache->res[feat_id]) == FEAT_SUPPORTED; } +bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) +{ + if (obj && obj->gen_loader) + /* To generate loader program assume the latest kernel + * to avoid doing extra prog_load, map_create syscalls. + */ + return true; + + return feat_supported(NULL, feat_id); +} + static bool map_is_reuse_compat(const struct bpf_map *map, int map_fd) { struct bpf_map_info map_info; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 58c547d473e0..622892fc841d 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -361,8 +361,11 @@ enum kern_feature_id { __FEAT_CNT, }; -int probe_memcg_account(void); +struct kern_feature_cache; +bool feat_supported(struct kern_feature_cache *cache, enum kern_feature_id feat_id); bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id); + +int probe_memcg_account(void); int bump_rlimit_memlock(void); int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz);