1 files changed, 224 insertions, 38 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 796b68d00119..c2ff608c1984 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -143,6 +143,8 @@ struct bpf_verifier_stack_elem {
 #define BPF_COMPLEXITY_LIMIT_INSNS	65536
 #define BPF_COMPLEXITY_LIMIT_STACK	1024
 
+#define BPF_MAP_PTR_POISON ((void *)0xeB9F + POISON_POINTER_DELTA)
+
 struct bpf_call_arg_meta {
 	struct bpf_map *map_ptr;
 	bool raw_mode;
@@ -765,38 +767,56 @@ static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
 	}
 }
 
-static int check_ptr_alignment(struct bpf_verifier_env *env,
-			       struct bpf_reg_state *reg, int off, int size)
+static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg,
+				   int off, int size)
 {
-	if (reg->type != PTR_TO_PACKET && reg->type != PTR_TO_MAP_VALUE_ADJ) {
-		if (off % size != 0) {
-			verbose("misaligned access off %d size %d\n",
-				off, size);
-			return -EACCES;
-		} else {
-			return 0;
-		}
-	}
-
-	if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
-		/* misaligned access to packet is ok on x86,arm,arm64 */
-		return 0;
-
 	if (reg->id && size != 1) {
-		verbose("Unknown packet alignment. Only byte-sized access allowed\n");
+		verbose("Unknown alignment. Only byte-sized access allowed in packet access.\n");
 		return -EACCES;
 	}
 
 	/* skb->data is NET_IP_ALIGN-ed */
-	if (reg->type == PTR_TO_PACKET &&
-	    (NET_IP_ALIGN + reg->off + off) % size != 0) {
+	if ((NET_IP_ALIGN + reg->off + off) % size != 0) {
 		verbose("misaligned packet access off %d+%d+%d size %d\n",
 			NET_IP_ALIGN, reg->off, off, size);
 		return -EACCES;
 	}
+
 	return 0;
 }
 
+static int check_val_ptr_alignment(const struct bpf_reg_state *reg,
+				   int size)
+{
+	if (size != 1) {
+		verbose("Unknown alignment. Only byte-sized access allowed in value access.\n");
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int check_ptr_alignment(const struct bpf_reg_state *reg,
+			       int off, int size)
+{
+	switch (reg->type) {
+	case PTR_TO_PACKET:
+		return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ? 0 :
+		       check_pkt_ptr_alignment(reg, off, size);
+	case PTR_TO_MAP_VALUE_ADJ:
+		return IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) ? 0 :
+		       check_val_ptr_alignment(reg, size);
+	default:
+		if (off % size != 0) {
+			verbose("misaligned access off %d size %d\n",
+				off, size);
+			return -EACCES;
+		}
+
+		return 0;
+	}
+}
+
 /* check whether memory at (regno + off) is accessible for t = (read | write)
  * if t==write, value_regno is a register which value is stored into memory
  * if t==read, value_regno is a register which will receive the value from memory
@@ -818,7 +838,7 @@ static int check_mem_access(struct bpf_verifier_env *env, u32 regno, int off,
 	if (size < 0)
 		return size;
 
-	err = check_ptr_alignment(env, reg, off, size);
+	err = check_ptr_alignment(reg, off, size);
 	if (err)
 		return err;
 
@@ -1197,6 +1217,10 @@ static int check_map_func_compatibility(struct bpf_map *map, int func_id)
 		    func_id != BPF_FUNC_current_task_under_cgroup)
 			goto error;
 		break;
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+		if (func_id != BPF_FUNC_map_lookup_elem)
+			goto error;
 	default:
 		break;
 	}
@@ -1273,7 +1297,7 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
 	}
 }
 
-static int check_call(struct bpf_verifier_env *env, int func_id)
+static int check_call(struct bpf_verifier_env *env, int func_id, int insn_idx)
 {
 	struct bpf_verifier_state *state = &env->cur_state;
 	const struct bpf_func_proto *fn = NULL;
@@ -1357,6 +1381,8 @@ static int check_call(struct bpf_verifier_env *env, int func_id)
 	} else if (fn->ret_type == RET_VOID) {
 		regs[BPF_REG_0].type = NOT_INIT;
 	} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) {
+		struct bpf_insn_aux_data *insn_aux;
+
 		regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
 		regs[BPF_REG_0].max_value = regs[BPF_REG_0].min_value = 0;
 		/* remember map_ptr, so that check_map_access()
@@ -1369,6 +1395,11 @@ static int check_call(struct bpf_verifier_env *env, int func_id)
 		}
 		regs[BPF_REG_0].map_ptr = meta.map_ptr;
 		regs[BPF_REG_0].id = ++env->id_gen;
+		insn_aux = &env->insn_aux_data[insn_idx];
+		if (!insn_aux->map_ptr)
+			insn_aux->map_ptr = meta.map_ptr;
+		else if (insn_aux->map_ptr != meta.map_ptr)
+			insn_aux->map_ptr = BPF_MAP_PTR_POISON;
 	} else {
 		verbose("unknown return type %d of func %s#%d\n",
 			fn->ret_type, func_id_name(func_id), func_id);
@@ -1893,6 +1924,17 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
 			return 0;
 		} else if (opcode == BPF_ADD &&
 			   BPF_CLASS(insn->code) == BPF_ALU64 &&
+			   dst_reg->type == PTR_TO_STACK &&
+			   ((BPF_SRC(insn->code) == BPF_X &&
+			     regs[insn->src_reg].type == CONST_IMM) ||
+			    BPF_SRC(insn->code) == BPF_K)) {
+			if (BPF_SRC(insn->code) == BPF_X)
+				dst_reg->imm += regs[insn->src_reg].imm;
+			else
+				dst_reg->imm += insn->imm;
+			return 0;
+		} else if (opcode == BPF_ADD &&
+			   BPF_CLASS(insn->code) == BPF_ALU64 &&
 			   (dst_reg->type == PTR_TO_PACKET ||
 			    (BPF_SRC(insn->code) == BPF_X &&
 			     regs[insn->src_reg].type == PTR_TO_PACKET))) {
@@ -1925,6 +1967,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
 		 * register as unknown.
 		 */
 		if (env->allow_ptr_leaks &&
+		    BPF_CLASS(insn->code) == BPF_ALU64 && opcode == BPF_ADD &&
 		    (dst_reg->type == PTR_TO_MAP_VALUE ||
 		     dst_reg->type == PTR_TO_MAP_VALUE_ADJ))
 			dst_reg->type = PTR_TO_MAP_VALUE_ADJ;
@@ -1973,14 +2016,15 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state,
 
 	for (i = 0; i < MAX_BPF_REG; i++)
 		if (regs[i].type == PTR_TO_PACKET && regs[i].id == dst_reg->id)
-			regs[i].range = dst_reg->off;
+			/* keep the maximum range already checked */
+			regs[i].range = max(regs[i].range, dst_reg->off);
 
 	for (i = 0; i < MAX_BPF_STACK; i += BPF_REG_SIZE) {
 		if (state->stack_slot_type[i] != STACK_SPILL)
 			continue;
 		reg = &state->spilled_regs[i / BPF_REG_SIZE];
 		if (reg->type == PTR_TO_PACKET && reg->id == dst_reg->id)
-			reg->range = dst_reg->off;
+			reg->range = max(reg->range, dst_reg->off);
 	}
 }
 
@@ -2092,14 +2136,19 @@ static void mark_map_reg(struct bpf_reg_state *regs, u32 regno, u32 id,
 	struct bpf_reg_state *reg = &regs[regno];
 
 	if (reg->type == PTR_TO_MAP_VALUE_OR_NULL && reg->id == id) {
-		reg->type = type;
+		if (type == UNKNOWN_VALUE) {
+			__mark_reg_unknown_value(regs, regno);
+		} else if (reg->map_ptr->inner_map_meta) {
+			reg->type = CONST_PTR_TO_MAP;
+			reg->map_ptr = reg->map_ptr->inner_map_meta;
+		} else {
+			reg->type = type;
+		}
 		/* We don't need id from this point onwards anymore, thus we
 		 * should better reset it, so that state pruning has chances
 		 * to take effect.
 		 */
 		reg->id = 0;
-		if (type == UNKNOWN_VALUE)
-			__mark_reg_unknown_value(regs, regno);
 	}
 }
 
@@ -2940,7 +2989,7 @@ static int do_check(struct bpf_verifier_env *env)
 					return -EINVAL;
 				}
 
-				err = check_call(env, insn->imm);
+				err = check_call(env, insn->imm, insn_idx);
 				if (err)
 					return err;
 
@@ -3024,16 +3073,33 @@ process_bpf_exit:
 	return 0;
 }
 
+static int check_map_prealloc(struct bpf_map *map)
+{
+	return (map->map_type != BPF_MAP_TYPE_HASH &&
+		map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&
+		map->map_type != BPF_MAP_TYPE_HASH_OF_MAPS) ||
+		!(map->map_flags & BPF_F_NO_PREALLOC);
+}
+
 static int check_map_prog_compatibility(struct bpf_map *map,
 					struct bpf_prog *prog)
 
 {
-	if (prog->type == BPF_PROG_TYPE_PERF_EVENT &&
-	    (map->map_type == BPF_MAP_TYPE_HASH ||
-	     map->map_type == BPF_MAP_TYPE_PERCPU_HASH) &&
-	    (map->map_flags & BPF_F_NO_PREALLOC)) {
-		verbose("perf_event programs can only use preallocated hash map\n");
-		return -EINVAL;
+	/* Make sure that BPF_PROG_TYPE_PERF_EVENT programs only use
+	 * preallocated hash maps, since doing memory allocation
+	 * in overflow_handler can crash depending on where nmi got
+	 * triggered.
+	 */
+	if (prog->type == BPF_PROG_TYPE_PERF_EVENT) {
+		if (!check_map_prealloc(map)) {
+			verbose("perf_event programs can only use preallocated hash map\n");
+			return -EINVAL;
+		}
+		if (map->inner_map_meta &&
+		    !check_map_prealloc(map->inner_map_meta)) {
+			verbose("perf_event programs can only use preallocated inner hash map\n");
+			return -EINVAL;
+		}
 	}
 	return 0;
 }
@@ -3162,6 +3228,41 @@ static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
 			insn->src_reg = 0;
 }
 
+/* single env->prog->insni[off] instruction was replaced with the range
+ * insni[off, off + cnt).  Adjust corresponding insn_aux_data by copying
+ * [0, off) and [off, end) to new locations, so the patched range stays zero
+ */
+static int adjust_insn_aux_data(struct bpf_verifier_env *env, u32 prog_len,
+				u32 off, u32 cnt)
+{
+	struct bpf_insn_aux_data *new_data, *old_data = env->insn_aux_data;
+
+	if (cnt == 1)
+		return 0;
+	new_data = vzalloc(sizeof(struct bpf_insn_aux_data) * prog_len);
+	if (!new_data)
+		return -ENOMEM;
+	memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
+	memcpy(new_data + off + cnt - 1, old_data + off,
+	       sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
+	env->insn_aux_data = new_data;
+	vfree(old_data);
+	return 0;
+}
+
+static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
+					    const struct bpf_insn *patch, u32 len)
+{
+	struct bpf_prog *new_prog;
+
+	new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
+	if (!new_prog)
+		return NULL;
+	if (adjust_insn_aux_data(env, new_prog->len, off, len))
+		return NULL;
+	return new_prog;
+}
+
 /* convert load instructions that access fields of 'struct __sk_buff'
  * into sequence of instructions that access fields of 'struct sk_buff'
  */
@@ -3181,10 +3282,10 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 			verbose("bpf verifier is misconfigured\n");
 			return -EINVAL;
 		} else if (cnt) {
-			new_prog = bpf_patch_insn_single(env->prog, 0,
-							 insn_buf, cnt);
+			new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
 			if (!new_prog)
 				return -ENOMEM;
+
 			env->prog = new_prog;
 			delta += cnt - 1;
 		}
@@ -3209,7 +3310,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 		else
 			continue;
 
-		if (env->insn_aux_data[i].ptr_type != PTR_TO_CTX)
+		if (env->insn_aux_data[i + delta].ptr_type != PTR_TO_CTX)
 			continue;
 
 		cnt = ops->convert_ctx_access(type, insn, insn_buf, env->prog);
@@ -3218,8 +3319,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 			return -EINVAL;
 		}
 
-		new_prog = bpf_patch_insn_single(env->prog, i + delta, insn_buf,
-						 cnt);
+		new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
 		if (!new_prog)
 			return -ENOMEM;
 
@@ -3233,6 +3333,89 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
 	return 0;
 }
 
+/* fixup insn->imm field of bpf_call instructions
+ * and inline eligible helpers as explicit sequence of BPF instructions
+ *
+ * this function is called after eBPF program passed verification
+ */
+static int fixup_bpf_calls(struct bpf_verifier_env *env)
+{
+	struct bpf_prog *prog = env->prog;
+	struct bpf_insn *insn = prog->insnsi;
+	const struct bpf_func_proto *fn;
+	const int insn_cnt = prog->len;
+	struct bpf_insn insn_buf[16];
+	struct bpf_prog *new_prog;
+	struct bpf_map *map_ptr;
+	int i, cnt, delta = 0;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (insn->code != (BPF_JMP | BPF_CALL))
+			continue;
+
+		if (insn->imm == BPF_FUNC_get_route_realm)
+			prog->dst_needed = 1;
+		if (insn->imm == BPF_FUNC_get_prandom_u32)
+			bpf_user_rnd_init_once();
+		if (insn->imm == BPF_FUNC_tail_call) {
+			/* If we tail call into other programs, we
+			 * cannot make any assumptions since they can
+			 * be replaced dynamically during runtime in
+			 * the program array.
+			 */
+			prog->cb_access = 1;
+
+			/* mark bpf_tail_call as different opcode to avoid
+			 * conditional branch in the interpeter for every normal
+			 * call and to prevent accidental JITing by JIT compiler
+			 * that doesn't support bpf_tail_call yet
+			 */
+			insn->imm = 0;
+			insn->code |= BPF_X;
+			continue;
+		}
+
+		if (ebpf_jit_enabled() && insn->imm == BPF_FUNC_map_lookup_elem) {
+			map_ptr = env->insn_aux_data[i + delta].map_ptr;
+			if (map_ptr == BPF_MAP_PTR_POISON ||
+			    !map_ptr->ops->map_gen_lookup)
+				goto patch_call_imm;
+
+			cnt = map_ptr->ops->map_gen_lookup(map_ptr, insn_buf);
+			if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+				verbose("bpf verifier is misconfigured\n");
+				return -EINVAL;
+			}
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
+						       cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta += cnt - 1;
+
+			/* keep walking new program and skip insns we just inserted */
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+patch_call_imm:
+		fn = prog->aux->ops->get_func_proto(insn->imm);
+		/* all functions that have prototype and verifier allowed
+		 * programs to call them, must be real in-kernel functions
+		 */
+		if (!fn->func) {
+			verbose("kernel subsystem misconfigured func %s#%d\n",
+				func_id_name(insn->imm), insn->imm);
+			return -EFAULT;
+		}
+		insn->imm = fn->func - __bpf_call_base;
+	}
+
+	return 0;
+}
+
 static void free_states(struct bpf_verifier_env *env)
 {
 	struct bpf_verifier_state_list *sl, *sln;
@@ -3328,6 +3511,9 @@ skip_full_check:
 		/* program is valid, convert *(u32*)(ctx + off) accesses */
 		ret = convert_ctx_accesses(env);
 
+	if (ret == 0)
+		ret = fixup_bpf_calls(env);
+
 	if (log_level && log_len >= log_size - 1) {
 		BUG_ON(log_len >= log_size);
 		/* verifier log exceeded user supplied buffer */