[RESEND,v3,bpf-next,10/14] bpf: add BPF token support to BPF_PROG_LOAD command

Message ID	20230629051832.897119-11-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 10/14] bpf: add BPF token support to BPF_PROG_LOAD command Date: Wed, 28 Jun 2023 22:18:28 -0700 Message-ID: <20230629051832.897119-11-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 856a147c8ce8..64dcdc18f09a 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1411,6 +1411,7 @@ struct bpf_prog_aux { #ifdef CONFIG_SECURITY void *security; #endif + struct bpf_token *token; struct bpf_prog_offload *offload; struct btf *btf; struct bpf_func_info *func_info; @@ -1540,6 +1541,8 @@ struct bpf_token { atomic64_t refcnt; u64 allowed_cmds; u64 allowed_map_types; + u64 allowed_prog_types; + u64 allowed_attach_types; }; struct bpf_struct_ops_value; @@ -2099,6 +2102,9 @@ 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); +bool bpf_token_allow_prog_type(const struct bpf_token *token, + enum bpf_prog_type prog_type, + enum bpf_attach_type attach_type); enum bpf_type { BPF_TYPE_UNSPEC = 0, diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index fa6a9e2396e6..6a37ba2f422d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1007,6 +1007,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_SK_LOOKUP, BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */ BPF_PROG_TYPE_NETFILTER, + __MAX_BPF_PROG_TYPE }; enum bpf_attach_type { @@ -1439,6 +1440,7 @@ union bpf_attr { * truncated), or smaller (if log buffer wasn't filled completely). */ __u32 log_true_size; + __u32 prog_token_fd; }; struct { /* anonymous struct used by BPF_OBJ_* commands */ @@ -1665,6 +1667,12 @@ union bpf_attr { * are allowed to be created by requested BPF token; */ __u64 allowed_map_types; + /* similarly to allowed_map_types, bit sets of BPF program + * types and BPF program attach types that are allowed to be + * loaded by requested BPF token + */ + __u64 allowed_prog_types; + __u64 allowed_attach_types; } token_create; } __attribute__((aligned(8))); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index dc85240a0134..2ed54d1ed32a 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2599,6 +2599,7 @@ void bpf_prog_free(struct bpf_prog *fp) if (aux->dst_prog) bpf_prog_put(aux->dst_prog); + bpf_token_put(aux->token); INIT_WORK(&aux->work, bpf_prog_free_deferred); schedule_work(&aux->work); } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index f295458a35c0..b9e7cc72429e 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2577,13 +2577,15 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type) } /* last field in 'union bpf_attr' used by this command */ -#define BPF_PROG_LOAD_LAST_FIELD log_true_size +#define BPF_PROG_LOAD_LAST_FIELD prog_token_fd static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) { enum bpf_prog_type type = attr->prog_type; struct bpf_prog *prog, *dst_prog = NULL; struct btf *attach_btf = NULL; + struct bpf_token *token = NULL; + bool bpf_cap; int err; char license[128]; @@ -2599,10 +2601,31 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) BPF_F_XDP_DEV_BOUND_ONLY)) return -EINVAL; + bpf_prog_load_fixup_attach_type(attr); + + if (attr->prog_token_fd) { + token = bpf_token_get_from_fd(attr->prog_token_fd); + if (IS_ERR(token)) + return PTR_ERR(token); + /* if current token doesn't grant prog loading 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_PROG_LOAD) || + !bpf_token_allow_prog_type(token, attr->prog_type, + attr->expected_attach_type)) { + bpf_token_put(token); + token = NULL; + } + } + + bpf_cap = bpf_token_capable(token, CAP_BPF); + err = -EPERM; + if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && (attr->prog_flags & BPF_F_ANY_ALIGNMENT) && - !bpf_capable()) - return -EPERM; + !bpf_cap) + goto put_token; /* Intent here is for unprivileged_bpf_disabled to block BPF program * creation for unprivileged users; other actions depend @@ -2611,21 +2634,23 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) * capability checks are still carried out for these * and other operations. */ - if (sysctl_unprivileged_bpf_disabled && !bpf_capable()) - return -EPERM; + if (sysctl_unprivileged_bpf_disabled && !bpf_cap) + goto put_token; if (attr->insn_cnt == 0 || - attr->insn_cnt > (bpf_capable() ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS)) - return -E2BIG; + attr->insn_cnt > (bpf_cap ? BPF_COMPLEXITY_LIMIT_INSNS : BPF_MAXINSNS)) { + err = -E2BIG; + goto put_token; + } if (type != BPF_PROG_TYPE_SOCKET_FILTER && type != BPF_PROG_TYPE_CGROUP_SKB && - !bpf_capable()) - return -EPERM; + !bpf_cap) + goto put_token; - if (is_net_admin_prog_type(type) && !capable(CAP_NET_ADMIN) && !capable(CAP_SYS_ADMIN)) - return -EPERM; - if (is_perfmon_prog_type(type) && !perfmon_capable()) - return -EPERM; + if (is_net_admin_prog_type(type) && !bpf_token_capable(token, CAP_NET_ADMIN)) + goto put_token; + if (is_perfmon_prog_type(type) && !bpf_token_capable(token, CAP_PERFMON)) + goto put_token; /* attach_prog_fd/attach_btf_obj_fd can specify fd of either bpf_prog * or btf, we need to check which one it is @@ -2635,27 +2660,33 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) if (IS_ERR(dst_prog)) { dst_prog = NULL; attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd); - if (IS_ERR(attach_btf)) - return -EINVAL; + if (IS_ERR(attach_btf)) { + err = -EINVAL; + goto put_token; + } if (!btf_is_kernel(attach_btf)) { /* attaching through specifying bpf_prog's BTF * objects directly might be supported eventually */ btf_put(attach_btf); - return -ENOTSUPP; + err = -ENOTSUPP; + goto put_token; } } } else if (attr->attach_btf_id) { /* fall back to vmlinux BTF, if BTF type ID is specified */ attach_btf = bpf_get_btf_vmlinux(); - if (IS_ERR(attach_btf)) - return PTR_ERR(attach_btf); - if (!attach_btf) - return -EINVAL; + if (IS_ERR(attach_btf)) { + err = PTR_ERR(attach_btf); + goto put_token; + } + if (!attach_btf) { + err = -EINVAL; + goto put_token; + } btf_get(attach_btf); } - bpf_prog_load_fixup_attach_type(attr); if (bpf_prog_load_check_attach(type, attr->expected_attach_type, attach_btf, attr->attach_btf_id, dst_prog)) { @@ -2663,7 +2694,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) bpf_prog_put(dst_prog); if (attach_btf) btf_put(attach_btf); - return -EINVAL; + err = -EINVAL; + goto put_token; } /* plain bpf_prog allocation */ @@ -2673,7 +2705,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) bpf_prog_put(dst_prog); if (attach_btf) btf_put(attach_btf); - return -ENOMEM; + err = -EINVAL; + goto put_token; } prog->expected_attach_type = attr->expected_attach_type; @@ -2684,6 +2717,10 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) prog->aux->sleepable = attr->prog_flags & BPF_F_SLEEPABLE; prog->aux->xdp_has_frags = attr->prog_flags & BPF_F_XDP_HAS_FRAGS; + /* move token into prog->aux, reuse taken refcnt */ + prog->aux->token = token; + token = NULL; + err = security_bpf_prog_alloc(prog->aux); if (err) goto free_prog; @@ -2785,6 +2822,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size) if (prog->aux->attach_btf) btf_put(prog->aux->attach_btf); bpf_prog_free(prog); +put_token: + bpf_token_put(token); return err; } @@ -3544,7 +3583,7 @@ static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog, case BPF_PROG_TYPE_SK_LOOKUP: return attach_type == prog->expected_attach_type ? 0 : -EINVAL; case BPF_PROG_TYPE_CGROUP_SKB: - if (!capable(CAP_NET_ADMIN)) + if (!bpf_token_capable(prog->aux->token, CAP_NET_ADMIN)) /* cg-skb progs can be loaded by unpriv user. * check permissions at attach time. */ @@ -5143,7 +5182,7 @@ static int bpf_prog_bind_map(union bpf_attr *attr) return ret; } -#define BPF_TOKEN_CREATE_LAST_FIELD token_create.allowed_map_types +#define BPF_TOKEN_CREATE_LAST_FIELD token_create.allowed_attach_types static int token_create(union bpf_attr *attr) { diff --git a/kernel/bpf/token.c b/kernel/bpf/token.c index 91d8d987faea..22449a509048 100644 --- a/kernel/bpf/token.c +++ b/kernel/bpf/token.c @@ -114,6 +114,14 @@ int bpf_token_create(union bpf_attr *attr) if (token && !is_bit_subset_of(attr->token_create.allowed_map_types, token->allowed_map_types)) goto out; + /* requested prog types should be a subset of associated token's set */ + if (token && !is_bit_subset_of(attr->token_create.allowed_prog_types, + token->allowed_prog_types)) + goto out; + /* requested attach types should be a subset of associated token's set */ + if (token && !is_bit_subset_of(attr->token_create.allowed_attach_types, + token->allowed_attach_types)) + goto out; new_token = bpf_token_alloc(); if (!new_token) { @@ -123,6 +131,8 @@ 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; + new_token->allowed_prog_types = attr->token_create.allowed_prog_types; + new_token->allowed_attach_types = attr->token_create.allowed_attach_types; ret = bpf_obj_pin_any(attr->token_create.pin_path_fd, u64_to_user_ptr(attr->token_create.pin_pathname), @@ -178,3 +188,14 @@ bool bpf_token_allow_map_type(const struct bpf_token *token, enum bpf_map_type t return token->allowed_map_types & (1ULL << type); } + +bool bpf_token_allow_prog_type(const struct bpf_token *token, + enum bpf_prog_type prog_type, + enum bpf_attach_type attach_type) +{ + if (!token || prog_type >= __MAX_BPF_PROG_TYPE || attach_type >= __MAX_BPF_ATTACH_TYPE) + return false; + + return (token->allowed_prog_types & (1ULL << prog_type)) && + (token->allowed_attach_types & (1ULL << attach_type)); +} diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index fa6a9e2396e6..6a37ba2f422d 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1007,6 +1007,7 @@ enum bpf_prog_type { BPF_PROG_TYPE_SK_LOOKUP, BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */ BPF_PROG_TYPE_NETFILTER, + __MAX_BPF_PROG_TYPE }; enum bpf_attach_type { @@ -1439,6 +1440,7 @@ union bpf_attr { * truncated), or smaller (if log buffer wasn't filled completely). */ __u32 log_true_size; + __u32 prog_token_fd; }; struct { /* anonymous struct used by BPF_OBJ_* commands */ @@ -1665,6 +1667,12 @@ union bpf_attr { * are allowed to be created by requested BPF token; */ __u64 allowed_map_types; + /* similarly to allowed_map_types, bit sets of BPF program + * types and BPF program attach types that are allowed to be + * loaded by requested BPF token + */ + __u64 allowed_prog_types; + __u64 allowed_attach_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 573249a2814d..4ed46ed58a7b 100644 --- a/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_probes.c @@ -30,6 +30,8 @@ void test_libbpf_probe_prog_types(void) if (prog_type == BPF_PROG_TYPE_UNSPEC) continue; + if (strcmp(prog_type_name, "__MAX_BPF_PROG_TYPE") == 0) + continue; if (!test__start_subtest(prog_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 e677c0435cec..ea2a8c4063a8 100644 --- a/tools/testing/selftests/bpf/prog_tests/libbpf_str.c +++ b/tools/testing/selftests/bpf/prog_tests/libbpf_str.c @@ -185,6 +185,9 @@ static void test_libbpf_bpf_prog_type_str(void) const char *prog_type_str; char buf[256]; + if (prog_type == __MAX_BPF_PROG_TYPE) + continue; + prog_type_name = btf__str_by_offset(btf, e->name_off); prog_type_str = libbpf_bpf_prog_type_str(prog_type); ASSERT_OK_PTR(prog_type_str, prog_type_name);

[RESEND,v3,bpf-next,10/14] bpf: add BPF token support to BPF_PROG_LOAD command

Commit Message

Patch