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Date: Thu, 30 Nov 2023 10:52:20 -0800
From: Andrii Nakryiko <andrii@...nel.org>
To: <bpf@...r.kernel.org>, <netdev@...r.kernel.org>, <paul@...l-moore.com>,
        <brauner@...nel.org>
CC: <linux-fsdevel@...r.kernel.org>, <linux-security-module@...r.kernel.org>,
        <keescook@...omium.org>, <kernel-team@...a.com>, <sargun@...gun.me>
Subject: [PATCH v12 bpf-next 08/17] bpf: consistently use BPF token throughout BPF verifier logic

Remove remaining direct queries to perfmon_capable() and bpf_capable()
in BPF verifier logic and instead use BPF token (if available) to make
decisions about privileges.

Signed-off-by: Andrii Nakryiko <andrii@...nel.org>
---
 include/linux/bpf.h    | 16 ++++++++--------
 include/linux/filter.h |  2 +-
 kernel/bpf/arraymap.c  |  2 +-
 kernel/bpf/core.c      |  2 +-
 kernel/bpf/verifier.c  | 13 ++++++-------
 net/core/filter.c      |  4 ++--
 6 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index eaeb9a71bc5d..a615b1a2c4e7 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2189,24 +2189,24 @@ extern int sysctl_unprivileged_bpf_disabled;
 
 bool bpf_token_capable(const struct bpf_token *token, int cap);
 
-static inline bool bpf_allow_ptr_leaks(void)
+static inline bool bpf_allow_ptr_leaks(const struct bpf_token *token)
 {
-	return perfmon_capable();
+	return bpf_token_capable(token, CAP_PERFMON);
 }
 
-static inline bool bpf_allow_uninit_stack(void)
+static inline bool bpf_allow_uninit_stack(const struct bpf_token *token)
 {
-	return perfmon_capable();
+	return bpf_token_capable(token, CAP_PERFMON);
 }
 
-static inline bool bpf_bypass_spec_v1(void)
+static inline bool bpf_bypass_spec_v1(const struct bpf_token *token)
 {
-	return cpu_mitigations_off() || perfmon_capable();
+	return cpu_mitigations_off() || bpf_token_capable(token, CAP_PERFMON);
 }
 
-static inline bool bpf_bypass_spec_v4(void)
+static inline bool bpf_bypass_spec_v4(const struct bpf_token *token)
 {
-	return cpu_mitigations_off() || perfmon_capable();
+	return cpu_mitigations_off() || bpf_token_capable(token, CAP_PERFMON);
 }
 
 int bpf_map_new_fd(struct bpf_map *map, int flags);
diff --git a/include/linux/filter.h b/include/linux/filter.h
index a4953fafc8cb..14354605ad26 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -1139,7 +1139,7 @@ static inline bool bpf_jit_blinding_enabled(struct bpf_prog *prog)
 		return false;
 	if (!bpf_jit_harden)
 		return false;
-	if (bpf_jit_harden == 1 && bpf_capable())
+	if (bpf_jit_harden == 1 && bpf_token_capable(prog->aux->token, CAP_BPF))
 		return false;
 
 	return true;
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 2058e89b5ddd..f0c64df6b6ff 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -82,7 +82,7 @@ static struct bpf_map *array_map_alloc(union bpf_attr *attr)
 	bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_ARRAY;
 	int numa_node = bpf_map_attr_numa_node(attr);
 	u32 elem_size, index_mask, max_entries;
-	bool bypass_spec_v1 = bpf_bypass_spec_v1();
+	bool bypass_spec_v1 = bpf_bypass_spec_v1(NULL);
 	u64 array_size, mask64;
 	struct bpf_array *array;
 
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index e4122334bfd9..fa229fe03a04 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -675,7 +675,7 @@ static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
 {
 	if (!bpf_prog_kallsyms_candidate(fp) ||
-	    !bpf_capable())
+	    !bpf_token_capable(fp->aux->token, CAP_BPF))
 		return;
 
 	bpf_prog_ksym_set_addr(fp);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8e7b6072e3f4..0dd39ed0b68f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -20509,7 +20509,12 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
 	env->prog = *prog;
 	env->ops = bpf_verifier_ops[env->prog->type];
 	env->fd_array = make_bpfptr(attr->fd_array, uattr.is_kernel);
-	is_priv = bpf_capable();
+
+	env->allow_ptr_leaks = bpf_allow_ptr_leaks(env->prog->aux->token);
+	env->allow_uninit_stack = bpf_allow_uninit_stack(env->prog->aux->token);
+	env->bypass_spec_v1 = bpf_bypass_spec_v1(env->prog->aux->token);
+	env->bypass_spec_v4 = bpf_bypass_spec_v4(env->prog->aux->token);
+	env->bpf_capable = is_priv = bpf_token_capable(env->prog->aux->token, CAP_BPF);
 
 	bpf_get_btf_vmlinux();
 
@@ -20541,12 +20546,6 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
 	if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
 		env->strict_alignment = false;
 
-	env->allow_ptr_leaks = bpf_allow_ptr_leaks();
-	env->allow_uninit_stack = bpf_allow_uninit_stack();
-	env->bypass_spec_v1 = bpf_bypass_spec_v1();
-	env->bypass_spec_v4 = bpf_bypass_spec_v4();
-	env->bpf_capable = bpf_capable();
-
 	if (is_priv)
 		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
 	env->test_reg_invariants = attr->prog_flags & BPF_F_TEST_REG_INVARIANTS;
diff --git a/net/core/filter.c b/net/core/filter.c
index bce53685d39a..3424947f1db2 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -8566,7 +8566,7 @@ static bool cg_skb_is_valid_access(int off, int size,
 		return false;
 	case bpf_ctx_range(struct __sk_buff, data):
 	case bpf_ctx_range(struct __sk_buff, data_end):
-		if (!bpf_capable())
+		if (!bpf_token_capable(prog->aux->token, CAP_BPF))
 			return false;
 		break;
 	}
@@ -8578,7 +8578,7 @@ static bool cg_skb_is_valid_access(int off, int size,
 		case bpf_ctx_range_till(struct __sk_buff, cb[0], cb[4]):
 			break;
 		case bpf_ctx_range(struct __sk_buff, tstamp):
-			if (!bpf_capable())
+			if (!bpf_token_capable(prog->aux->token, CAP_BPF))
 				return false;
 			break;
 		default:
-- 
2.34.1


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