[RESEND,v3,bpf-next,04/14] bpf: add BPF token support to BPF_MAP_CREATE command

Message ID	20230629051832.897119-5-andrii@kernel.org (mailing list archive)
State	Changes Requested
Delegated to:	Paul Moore
Headers	show Return-Path: <linux-security-module-owner@vger.kernel.org> From: Andrii Nakryiko <andrii@kernel.org> To: <bpf@vger.kernel.org> CC: <linux-security-module@vger.kernel.org>, <keescook@chromium.org>, <brauner@kernel.org>, <lennart@poettering.net>, <cyphar@cyphar.com>, <luto@kernel.org>, <kernel-team@meta.com>, <sargun@sargun.me> Subject: [PATCH RESEND v3 bpf-next 04/14] bpf: add BPF token support to BPF_MAP_CREATE command Date: Wed, 28 Jun 2023 22:18:22 -0700 Message-ID: <20230629051832.897119-5-andrii@kernel.org> In-Reply-To: <20230629051832.897119-1-andrii@kernel.org> References: <20230629051832.897119-1-andrii@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain Precedence: bulk
Series	BPF token \| expand [RESEND,v3,bpf-next,00/14] BPF token [RESEND,v3,bpf-next,01/14] bpf: introduce BPF token object [RESEND,v3,bpf-next,02/14] libbpf: add bpf_token_create() API [RESEND,v3,bpf-next,03/14] selftests/bpf: add BPF_TOKEN_CREATE test [RESEND,v3,bpf-next,04/14] bpf: add BPF token support to BPF_MAP_CREATE command [RESEND,v3,bpf-next,05/14] libbpf: add BPF token support to bpf_map_create() API [RESEND,v3,bpf-next,06/14] selftests/bpf: add BPF token-enabled test for BPF_MAP_CREATE command [RESEND,v3,bpf-next,07/14] bpf: add BPF token support to BPF_BTF_LOAD command [RESEND,v3,bpf-next,08/14] libbpf: add BPF token support to bpf_btf_load() API [RESEND,v3,bpf-next,09/14] selftests/bpf: add BPF token-enabled BPF_BTF_LOAD selftest [RESEND,v3,bpf-next,10/14] bpf: add BPF token support to BPF_PROG_LOAD command [RESEND,v3,bpf-next,11/14] bpf: take into account BPF token when fetching helper protos [RESEND,v3,bpf-next,12/14] bpf: consistenly use BPF token throughout BPF verifier logic [RESEND,v3,bpf-next,13/14] libbpf: add BPF token support to bpf_prog_load() API [RESEND,v3,bpf-next,14/14] selftests/bpf: add BPF token-enabled BPF_PROG_LOAD tests

diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c4f1684aa138..856a147c8ce8 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -251,6 +251,7 @@ struct bpf_map { u32 btf_value_type_id; u32 btf_vmlinux_value_type_id; struct btf *btf; + struct bpf_token *token; #ifdef CONFIG_MEMCG_KMEM struct obj_cgroup *objcg; #endif @@ -1538,6 +1539,7 @@ struct bpf_token { struct work_struct work; atomic64_t refcnt; u64 allowed_cmds; + u64 allowed_map_types; }; struct bpf_struct_ops_value; @@ -2096,6 +2098,7 @@ int bpf_token_new_fd(struct bpf_token *token); struct bpf_token *bpf_token_get_from_fd(u32 ufd); bool bpf_token_allow_cmd(const struct bpf_token *token, enum bpf_cmd cmd); +bool bpf_token_allow_map_type(const struct bpf_token *token, enum bpf_map_type type); enum bpf_type { BPF_TYPE_UNSPEC = 0, diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3ff91f52745d..59764ba48ec9 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -962,6 +962,7 @@ enum bpf_map_type { BPF_MAP_TYPE_BLOOM_FILTER, BPF_MAP_TYPE_USER_RINGBUF, BPF_MAP_TYPE_CGRP_STORAGE, + __MAX_BPF_MAP_TYPE }; /* Note that tracing related programs such as @@ -1368,6 +1369,7 @@ union bpf_attr { * to using 5 hash functions). */ __u64 map_extra; + __u32 map_token_fd; }; struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */ @@ -1658,6 +1660,10 @@ union bpf_attr { * programs */ __u64 allowed_cmds; + /* similarly to allowed_cmds, a bit set of BPF map types that + * are allowed to be created by requested BPF token; + */ + __u64 allowed_map_types; } token_create; } __attribute__((aligned(8))); diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 745b605fad8e..cc15b1d5dc26 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -691,6 +691,7 @@ static void bpf_map_free_deferred(struct work_struct *work) { struct bpf_map *map = container_of(work, struct bpf_map, work); struct btf_record *rec = map->record; + struct bpf_token *token = map->token; security_bpf_map_free(map); bpf_map_release_memcg(map); @@ -706,6 +707,7 @@ static void bpf_map_free_deferred(struct work_struct *work) * template bpf_map struct used during verification. */ btf_record_free(rec); + bpf_token_put(token); } static void bpf_map_put_uref(struct bpf_map *map) @@ -1010,7 +1012,7 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, if (!IS_ERR_OR_NULL(map->record)) { int i; - if (!bpf_capable()) { + if (!bpf_token_capable(map->token, CAP_BPF)) { ret = -EPERM; goto free_map_tab; } @@ -1092,11 +1094,12 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf, return ret; } -#define BPF_MAP_CREATE_LAST_FIELD map_extra +#define BPF_MAP_CREATE_LAST_FIELD map_token_fd /* called via syscall */ static int map_create(union bpf_attr *attr) { const struct bpf_map_ops *ops; + struct bpf_token *token = NULL; int numa_node = bpf_map_attr_numa_node(attr); u32 map_type = attr->map_type; struct bpf_map *map; @@ -1147,14 +1150,32 @@ static int map_create(union bpf_attr *attr) if (!ops->map_mem_usage) return -EINVAL; + if (attr->map_token_fd) { + token = bpf_token_get_from_fd(attr->map_token_fd); + if (IS_ERR(token)) + return PTR_ERR(token); + + /* if current token doesn't grant map creation permissions, + * then we can't use this token, so ignore it and rely on + * system-wide capabilities checks + */ + if (!bpf_token_allow_cmd(token, BPF_MAP_CREATE) || + !bpf_token_allow_map_type(token, attr->map_type)) { + bpf_token_put(token); + token = NULL; + } + } + + err = -EPERM; + /* Intent here is for unprivileged_bpf_disabled to block BPF map * creation for unprivileged users; other actions depend * on fd availability and access to bpffs, so are dependent on * object creation success. Even with unprivileged BPF disabled, * capability checks are still carried out. */ - if (sysctl_unprivileged_bpf_disabled && !bpf_capable()) - return -EPERM; + if (sysctl_unprivileged_bpf_disabled && !bpf_token_capable(token, CAP_BPF)) + goto put_token; /* check privileged map type permissions */ switch (map_type) { @@ -1187,28 +1208,36 @@ static int map_create(union bpf_attr *attr) case BPF_MAP_TYPE_LRU_PERCPU_HASH: case BPF_MAP_TYPE_STRUCT_OPS: case BPF_MAP_TYPE_CPUMAP: - if (!bpf_capable()) - return -EPERM; + if (!bpf_token_capable(token, CAP_BPF)) + goto put_token; break; case BPF_MAP_TYPE_SOCKMAP: case BPF_MAP_TYPE_SOCKHASH: case BPF_MAP_TYPE_DEVMAP: case BPF_MAP_TYPE_DEVMAP_HASH: case BPF_MAP_TYPE_XSKMAP: - if (!capable(CAP_NET_ADMIN)) - return -EPERM; + if (!bpf_token_capable(token, CAP_NET_ADMIN)) + goto put_token; break; default: WARN(1, "unsupported map type %d", map_type); - return -EPERM; + goto put_token; } map = ops->map_alloc(attr); - if (IS_ERR(map)) - return PTR_ERR(map); + if (IS_ERR(map)) { + err = PTR_ERR(map); + goto put_token; + } map->ops = ops; map->map_type = map_type; + if (token) { + /* move token reference into map->token, reuse our refcnt */ + map->token = token; + token = NULL; + } + err = bpf_obj_name_cpy(map->name, attr->map_name, sizeof(attr->map_name)); if (err < 0) @@ -1281,8 +1310,11 @@ static int map_create(union bpf_attr *attr) free_map_sec: security_bpf_map_free(map); free_map: + bpf_token_put(map->token); btf_put(map->btf); map->ops->map_free(map); +put_token: + bpf_token_put(token); return err; } @@ -5095,7 +5127,7 @@ static int bpf_prog_bind_map(union bpf_attr *attr) return ret; } -#define BPF_TOKEN_CREATE_LAST_FIELD token_create.allowed_cmds +#define BPF_TOKEN_CREATE_LAST_FIELD token_create.allowed_map_types static int token_create(union bpf_attr *attr) { diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c index 1ece52439701..91d8d987faea 100644 --- a/kernel/bpf/token.c +++ b/kernel/bpf/token.c @@ -110,6 +110,10 @@ int bpf_token_create(union bpf_attr *attr) /* requested cmds should be a subset of associated token's set */ if (token && !is_bit_subset_of(attr->token_create.allowed_cmds, token->allowed_cmds)) goto out; + /* requested map types should be a subset of associated token's set */ + if (token && !is_bit_subset_of(attr->token_create.allowed_map_types, + token->allowed_map_types)) + goto out; new_token = bpf_token_alloc(); if (!new_token) { @@ -118,6 +122,7 @@ int bpf_token_create(union bpf_attr *attr) } new_token->allowed_cmds = attr->token_create.allowed_cmds; + new_token->allowed_map_types = attr->token_create.allowed_map_types; ret = bpf_obj_pin_any(attr->token_create.pin_path_fd, u64_to_user_ptr(attr->token_create.pin_pathname), @@ -165,3 +170,11 @@ bool bpf_token_allow_cmd(const struct bpf_token *token, enum bpf_cmd cmd) return token->allowed_cmds & (1ULL << cmd); } + +bool bpf_token_allow_map_type(const struct bpf_token *token, enum bpf_map_type type) +{ + if (!token || type >= __MAX_BPF_MAP_TYPE) + return false; + + return token->allowed_map_types & (1ULL << type); +} diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 3ff91f52745d..59764ba48ec9 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -962,6 +962,7 @@ enum bpf_map_type { BPF_MAP_TYPE_BLOOM_FILTER, BPF_MAP_TYPE_USER_RINGBUF, BPF_MAP_TYPE_CGRP_STORAGE, + __MAX_BPF_MAP_TYPE }; /* Note that tracing related programs such as @@ -1368,6 +1369,7 @@ union bpf_attr { * to using 5 hash functions). */ __u64 map_extra; + __u32 map_token_fd; }; struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */ @@ -1658,6 +1660,10 @@ union bpf_attr { * programs */ __u64 allowed_cmds; + /* similarly to allowed_cmds, a bit set of BPF map types that + * are allowed to be created by requested BPF token; + */ + __u64 allowed_map_types; } token_create; } __attribute__((aligned(8))); diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c index 9f766ddd946a..573249a2814d 100644 --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c @@ -68,6 +68,8 @@ void test_libbpf_probe_map_types(void) if (map_type == BPF_MAP_TYPE_UNSPEC) continue; + if (strcmp(map_type_name, "__MAX_BPF_MAP_TYPE") == 0) + continue; if (!test__start_subtest(map_type_name)) continue; diff --git a/tools/testing/selftests/bpf/prog_tests/libbpf_str.c b/tools/testing/selftests/bpf/prog_tests/libbpf_str.c index efb8bd43653c..e677c0435cec 100644 --- a/tools/testing/selftests/bpf/prog_tests/libbpf_str.c +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_str.c @@ -132,6 +132,9 @@ static void test_libbpf_bpf_map_type_str(void) const char *map_type_str; char buf[256]; + if (map_type == __MAX_BPF_MAP_TYPE) + continue; + map_type_name = btf__str_by_offset(btf, e->name_off); map_type_str = libbpf_bpf_map_type_str(map_type); ASSERT_OK_PTR(map_type_str, map_type_name);

[RESEND,v3,bpf-next,04/14] bpf: add BPF token support to BPF_MAP_CREATE command

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Patch