1 files changed, 118 insertions, 44 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 757476c91c98..c6a27574242d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6409,18 +6409,10 @@ enum {
 };
 
 static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
-			      const struct bpf_reg_state *off_reg,
-			      u32 *alu_limit, u8 opcode)
+			      u32 *alu_limit, bool mask_to_left)
 {
-	bool off_is_neg = off_reg->smin_value < 0;
-	bool mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
-			    (opcode == BPF_SUB && !off_is_neg);
 	u32 max = 0, ptr_limit = 0;
 
-	if (!tnum_is_const(off_reg->var_off) &&
-	    (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
-		return REASON_BOUNDS;
-
 	switch (ptr_reg->type) {
 	case PTR_TO_STACK:
 		/* Offset 0 is out-of-bounds, but acceptable start for the
@@ -6486,15 +6478,41 @@ static bool sanitize_needed(u8 opcode)
 	return opcode == BPF_ADD || opcode == BPF_SUB;
 }
 
+struct bpf_sanitize_info {
+	struct bpf_insn_aux_data aux;
+	bool mask_to_left;
+};
+
+static struct bpf_verifier_state *
+sanitize_speculative_path(struct bpf_verifier_env *env,
+			  const struct bpf_insn *insn,
+			  u32 next_idx, u32 curr_idx)
+{
+	struct bpf_verifier_state *branch;
+	struct bpf_reg_state *regs;
+
+	branch = push_stack(env, next_idx, curr_idx, true);
+	if (branch && insn) {
+		regs = branch->frame[branch->curframe]->regs;
+		if (BPF_SRC(insn->code) == BPF_K) {
+			mark_reg_unknown(env, regs, insn->dst_reg);
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			mark_reg_unknown(env, regs, insn->src_reg);
+		}
+	}
+	return branch;
+}
+
 static int sanitize_ptr_alu(struct bpf_verifier_env *env,
 			    struct bpf_insn *insn,
 			    const struct bpf_reg_state *ptr_reg,
 			    const struct bpf_reg_state *off_reg,
 			    struct bpf_reg_state *dst_reg,
-			    struct bpf_insn_aux_data *tmp_aux,
+			    struct bpf_sanitize_info *info,
 			    const bool commit_window)
 {
-	struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : tmp_aux;
+	struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : &info->aux;
 	struct bpf_verifier_state *vstate = env->cur_state;
 	bool off_is_imm = tnum_is_const(off_reg->var_off);
 	bool off_is_neg = off_reg->smin_value < 0;
@@ -6515,7 +6533,16 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
 	if (vstate->speculative)
 		goto do_sim;
 
-	err = retrieve_ptr_limit(ptr_reg, off_reg, &alu_limit, opcode);
+	if (!commit_window) {
+		if (!tnum_is_const(off_reg->var_off) &&
+		    (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
+			return REASON_BOUNDS;
+
+		info->mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
+				     (opcode == BPF_SUB && !off_is_neg);
+	}
+
+	err = retrieve_ptr_limit(ptr_reg, &alu_limit, info->mask_to_left);
 	if (err < 0)
 		return err;
 
@@ -6523,8 +6550,8 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
 		/* In commit phase we narrow the masking window based on
 		 * the observed pointer move after the simulated operation.
 		 */
-		alu_state = tmp_aux->alu_state;
-		alu_limit = abs(tmp_aux->alu_limit - alu_limit);
+		alu_state = info->aux.alu_state;
+		alu_limit = abs(info->aux.alu_limit - alu_limit);
 	} else {
 		alu_state  = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
 		alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
@@ -6539,8 +6566,12 @@ do_sim:
 	/* If we're in commit phase, we're done here given we already
 	 * pushed the truncated dst_reg into the speculative verification
 	 * stack.
+	 *
+	 * Also, when register is a known constant, we rewrite register-based
+	 * operation to immediate-based, and thus do not need masking (and as
+	 * a consequence, do not need to simulate the zero-truncation either).
 	 */
-	if (commit_window)
+	if (commit_window || off_is_imm)
 		return 0;
 
 	/* Simulate and find potential out-of-bounds access under
@@ -6556,12 +6587,26 @@ do_sim:
 		tmp = *dst_reg;
 		*dst_reg = *ptr_reg;
 	}
-	ret = push_stack(env, env->insn_idx + 1, env->insn_idx, true);
+	ret = sanitize_speculative_path(env, NULL, env->insn_idx + 1,
+					env->insn_idx);
 	if (!ptr_is_dst_reg && ret)
 		*dst_reg = tmp;
 	return !ret ? REASON_STACK : 0;
 }
 
+static void sanitize_mark_insn_seen(struct bpf_verifier_env *env)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+
+	/* If we simulate paths under speculation, we don't update the
+	 * insn as 'seen' such that when we verify unreachable paths in
+	 * the non-speculative domain, sanitize_dead_code() can still
+	 * rewrite/sanitize them.
+	 */
+	if (!vstate->speculative)
+		env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
+}
+
 static int sanitize_err(struct bpf_verifier_env *env,
 			const struct bpf_insn *insn, int reason,
 			const struct bpf_reg_state *off_reg,
@@ -6685,7 +6730,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 	    smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
 	u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
 	    umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
-	struct bpf_insn_aux_data tmp_aux = {};
+	struct bpf_sanitize_info info = {};
 	u8 opcode = BPF_OP(insn->code);
 	u32 dst = insn->dst_reg;
 	int ret;
@@ -6754,7 +6799,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 
 	if (sanitize_needed(opcode)) {
 		ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
-				       &tmp_aux, false);
+				       &info, false);
 		if (ret < 0)
 			return sanitize_err(env, insn, ret, off_reg, dst_reg);
 	}
@@ -6895,7 +6940,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
 		return -EACCES;
 	if (sanitize_needed(opcode)) {
 		ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
-				       &tmp_aux, true);
+				       &info, true);
 		if (ret < 0)
 			return sanitize_err(env, insn, ret, off_reg, dst_reg);
 	}
@@ -7084,11 +7129,10 @@ static void scalar32_min_max_and(struct bpf_reg_state *dst_reg,
 	s32 smin_val = src_reg->s32_min_value;
 	u32 umax_val = src_reg->u32_max_value;
 
-	/* Assuming scalar64_min_max_and will be called so its safe
-	 * to skip updating register for known 32-bit case.
-	 */
-	if (src_known && dst_known)
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
 		return;
+	}
 
 	/* We get our minimum from the var_off, since that's inherently
 	 * bitwise.  Our maximum is the minimum of the operands' maxima.
@@ -7108,7 +7152,6 @@ static void scalar32_min_max_and(struct bpf_reg_state *dst_reg,
 		dst_reg->s32_min_value = dst_reg->u32_min_value;
 		dst_reg->s32_max_value = dst_reg->u32_max_value;
 	}
-
 }
 
 static void scalar_min_max_and(struct bpf_reg_state *dst_reg,
@@ -7155,11 +7198,10 @@ static void scalar32_min_max_or(struct bpf_reg_state *dst_reg,
 	s32 smin_val = src_reg->s32_min_value;
 	u32 umin_val = src_reg->u32_min_value;
 
-	/* Assuming scalar64_min_max_or will be called so it is safe
-	 * to skip updating register for known case.
-	 */
-	if (src_known && dst_known)
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
 		return;
+	}
 
 	/* We get our maximum from the var_off, and our minimum is the
 	 * maximum of the operands' minima
@@ -7224,11 +7266,10 @@ static void scalar32_min_max_xor(struct bpf_reg_state *dst_reg,
 	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
 	s32 smin_val = src_reg->s32_min_value;
 
-	/* Assuming scalar64_min_max_xor will be called so it is safe
-	 * to skip updating register for known case.
-	 */
-	if (src_known && dst_known)
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
 		return;
+	}
 
 	/* We get both minimum and maximum from the var32_off. */
 	dst_reg->u32_min_value = var32_off.value;
@@ -8744,14 +8785,28 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
 		if (err)
 			return err;
 	}
+
 	if (pred == 1) {
-		/* only follow the goto, ignore fall-through */
+		/* Only follow the goto, ignore fall-through. If needed, push
+		 * the fall-through branch for simulation under speculative
+		 * execution.
+		 */
+		if (!env->bypass_spec_v1 &&
+		    !sanitize_speculative_path(env, insn, *insn_idx + 1,
+					       *insn_idx))
+			return -EFAULT;
 		*insn_idx += insn->off;
 		return 0;
 	} else if (pred == 0) {
-		/* only follow fall-through branch, since
-		 * that's where the program will go
+		/* Only follow the fall-through branch, since that's where the
+		 * program will go. If needed, push the goto branch for
+		 * simulation under speculative execution.
 		 */
+		if (!env->bypass_spec_v1 &&
+		    !sanitize_speculative_path(env, insn,
+					       *insn_idx + insn->off + 1,
+					       *insn_idx))
+			return -EFAULT;
 		return 0;
 	}
 
@@ -10624,7 +10679,7 @@ static int do_check(struct bpf_verifier_env *env)
 		}
 
 		regs = cur_regs(env);
-		env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
+		sanitize_mark_insn_seen(env);
 		prev_insn_idx = env->insn_idx;
 
 		if (class == BPF_ALU || class == BPF_ALU64) {
@@ -10851,7 +10906,7 @@ process_bpf_exit:
 					return err;
 
 				env->insn_idx++;
-				env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
+				sanitize_mark_insn_seen(env);
 			} else {
 				verbose(env, "invalid BPF_LD mode\n");
 				return -EINVAL;
@@ -11360,6 +11415,7 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env,
 {
 	struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data;
 	struct bpf_insn *insn = new_prog->insnsi;
+	u32 old_seen = old_data[off].seen;
 	u32 prog_len;
 	int i;
 
@@ -11380,7 +11436,8 @@ static int adjust_insn_aux_data(struct bpf_verifier_env *env,
 	memcpy(new_data + off + cnt - 1, old_data + off,
 	       sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
 	for (i = off; i < off + cnt - 1; i++) {
-		new_data[i].seen = env->pass_cnt;
+		/* Expand insni[off]'s seen count to the patched range. */
+		new_data[i].seen = old_seen;
 		new_data[i].zext_dst = insn_has_def32(env, insn + i);
 	}
 	env->insn_aux_data = new_data;
@@ -12704,6 +12761,9 @@ static void free_states(struct bpf_verifier_env *env)
  * insn_aux_data was touched. These variables are compared to clear temporary
  * data from failed pass. For testing and experiments do_check_common() can be
  * run multiple times even when prior attempt to verify is unsuccessful.
+ *
+ * Note that special handling is needed on !env->bypass_spec_v1 if this is
+ * ever called outside of error path with subsequent program rejection.
  */
 static void sanitize_insn_aux_data(struct bpf_verifier_env *env)
 {
@@ -13200,6 +13260,17 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
 	return 0;
 }
 
+BTF_SET_START(btf_id_deny)
+BTF_ID_UNUSED
+#ifdef CONFIG_SMP
+BTF_ID(func, migrate_disable)
+BTF_ID(func, migrate_enable)
+#endif
+#if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
+BTF_ID(func, rcu_read_unlock_strict)
+#endif
+BTF_SET_END(btf_id_deny)
+
 static int check_attach_btf_id(struct bpf_verifier_env *env)
 {
 	struct bpf_prog *prog = env->prog;
@@ -13259,6 +13330,9 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
 		ret = bpf_lsm_verify_prog(&env->log, prog);
 		if (ret < 0)
 			return ret;
+	} else if (prog->type == BPF_PROG_TYPE_TRACING &&
+		   btf_id_set_contains(&btf_id_deny, btf_id)) {
+		return -EINVAL;
 	}
 
 	key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
@@ -13358,12 +13432,6 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	if (is_priv)
 		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
 
-	if (bpf_prog_is_dev_bound(env->prog->aux)) {
-		ret = bpf_prog_offload_verifier_prep(env->prog);
-		if (ret)
-			goto skip_full_check;
-	}
-
 	env->explored_states = kvcalloc(state_htab_size(env),
 				       sizeof(struct bpf_verifier_state_list *),
 				       GFP_USER);
@@ -13391,6 +13459,12 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	if (ret < 0)
 		goto skip_full_check;
 
+	if (bpf_prog_is_dev_bound(env->prog->aux)) {
+		ret = bpf_prog_offload_verifier_prep(env->prog);
+		if (ret)
+			goto skip_full_check;
+	}
+
 	ret = check_cfg(env);
 	if (ret < 0)
 		goto skip_full_check;