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-rw-r--r--kernel/bpf/verifier.c114
1 files changed, 86 insertions, 28 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index b914fbe1383e..f849eca36052 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -177,6 +177,12 @@ static __printf(1, 2) void verbose(const char *fmt, ...)
va_end(args);
}
+static bool type_is_pkt_pointer(enum bpf_reg_type type)
+{
+ return type == PTR_TO_PACKET ||
+ type == PTR_TO_PACKET_META;
+}
+
/* string representation of 'enum bpf_reg_type' */
static const char * const reg_type_str[] = {
[NOT_INIT] = "?",
@@ -187,6 +193,7 @@ static const char * const reg_type_str[] = {
[PTR_TO_MAP_VALUE_OR_NULL] = "map_value_or_null",
[PTR_TO_STACK] = "fp",
[PTR_TO_PACKET] = "pkt",
+ [PTR_TO_PACKET_META] = "pkt_meta",
[PTR_TO_PACKET_END] = "pkt_end",
};
@@ -226,7 +233,7 @@ static void print_verifier_state(struct bpf_verifier_state *state)
verbose("(id=%d", reg->id);
if (t != SCALAR_VALUE)
verbose(",off=%d", reg->off);
- if (t == PTR_TO_PACKET)
+ if (type_is_pkt_pointer(t))
verbose(",r=%d", reg->range);
else if (t == CONST_PTR_TO_MAP ||
t == PTR_TO_MAP_VALUE ||
@@ -519,6 +526,31 @@ static void mark_reg_known_zero(struct bpf_reg_state *regs, u32 regno)
__mark_reg_known_zero(regs + regno);
}
+static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
+{
+ return type_is_pkt_pointer(reg->type);
+}
+
+static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
+{
+ return reg_is_pkt_pointer(reg) ||
+ reg->type == PTR_TO_PACKET_END;
+}
+
+/* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
+static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
+ enum bpf_reg_type which)
+{
+ /* The register can already have a range from prior markings.
+ * This is fine as long as it hasn't been advanced from its
+ * origin.
+ */
+ return reg->type == which &&
+ reg->id == 0 &&
+ reg->off == 0 &&
+ tnum_equals_const(reg->var_off, 0);
+}
+
/* Attempts to improve min/max values based on var_off information */
static void __update_reg_bounds(struct bpf_reg_state *reg)
{
@@ -702,6 +734,7 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
case PTR_TO_STACK:
case PTR_TO_CTX:
case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
case PTR_TO_PACKET_END:
case CONST_PTR_TO_MAP:
return true;
@@ -1047,7 +1080,10 @@ static int check_ptr_alignment(struct bpf_verifier_env *env,
switch (reg->type) {
case PTR_TO_PACKET:
- /* special case, because of NET_IP_ALIGN */
+ case PTR_TO_PACKET_META:
+ /* Special case, because of NET_IP_ALIGN. Given metadata sits
+ * right in front, treat it the very same way.
+ */
return check_pkt_ptr_alignment(reg, off, size, strict);
case PTR_TO_MAP_VALUE:
pointer_desc = "value ";
@@ -1124,8 +1160,8 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
err = check_ctx_access(env, insn_idx, off, size, t, &reg_type);
if (!err && t == BPF_READ && value_regno >= 0) {
/* ctx access returns either a scalar, or a
- * PTR_TO_PACKET[_END]. In the latter case, we know
- * the offset is zero.
+ * PTR_TO_PACKET[_META,_END]. In the latter
+ * case, we know the offset is zero.
*/
if (reg_type == SCALAR_VALUE)
mark_reg_unknown(state->regs, value_regno);
@@ -1170,7 +1206,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
} else {
err = check_stack_read(state, off, size, value_regno);
}
- } else if (reg->type == PTR_TO_PACKET) {
+ } else if (reg_is_pkt_pointer(reg)) {
if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
verbose("cannot write into packet\n");
return -EACCES;
@@ -1310,6 +1346,7 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
switch (reg->type) {
case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
return check_packet_access(env, regno, reg->off, access_size);
case PTR_TO_MAP_VALUE:
return check_map_access(env, regno, reg->off, access_size);
@@ -1342,7 +1379,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
return 0;
}
- if (type == PTR_TO_PACKET &&
+ if (type_is_pkt_pointer(type) &&
!may_access_direct_pkt_data(env, meta, BPF_READ)) {
verbose("helper access to the packet is not allowed\n");
return -EACCES;
@@ -1351,7 +1388,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
if (arg_type == ARG_PTR_TO_MAP_KEY ||
arg_type == ARG_PTR_TO_MAP_VALUE) {
expected_type = PTR_TO_STACK;
- if (type != PTR_TO_PACKET && type != expected_type)
+ if (!type_is_pkt_pointer(type) &&
+ type != expected_type)
goto err_type;
} else if (arg_type == ARG_CONST_SIZE ||
arg_type == ARG_CONST_SIZE_OR_ZERO) {
@@ -1375,7 +1413,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
*/
if (register_is_null(*reg))
/* final test in check_stack_boundary() */;
- else if (type != PTR_TO_PACKET && type != PTR_TO_MAP_VALUE &&
+ else if (!type_is_pkt_pointer(type) &&
+ type != PTR_TO_MAP_VALUE &&
type != expected_type)
goto err_type;
meta->raw_mode = arg_type == ARG_PTR_TO_UNINIT_MEM;
@@ -1401,7 +1440,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
verbose("invalid map_ptr to access map->key\n");
return -EACCES;
}
- if (type == PTR_TO_PACKET)
+ if (type_is_pkt_pointer(type))
err = check_packet_access(env, regno, reg->off,
meta->map_ptr->key_size);
else
@@ -1417,7 +1456,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno,
verbose("invalid map_ptr to access map->value\n");
return -EACCES;
}
- if (type == PTR_TO_PACKET)
+ if (type_is_pkt_pointer(type))
err = check_packet_access(env, regno, reg->off,
meta->map_ptr->value_size);
else
@@ -1590,8 +1629,8 @@ static int check_raw_mode(const struct bpf_func_proto *fn)
return count > 1 ? -EINVAL : 0;
}
-/* Packet data might have moved, any old PTR_TO_PACKET[_END] are now invalid,
- * so turn them into unknown SCALAR_VALUE.
+/* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
+ * are now invalid, so turn them into unknown SCALAR_VALUE.
*/
static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
{
@@ -1600,18 +1639,15 @@ static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
int i;
for (i = 0; i < MAX_BPF_REG; i++)
- if (regs[i].type == PTR_TO_PACKET ||
- regs[i].type == PTR_TO_PACKET_END)
+ if (reg_is_pkt_pointer_any(&regs[i]))
mark_reg_unknown(regs, i);
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->type != PTR_TO_PACKET_END)
- continue;
- __mark_reg_unknown(reg);
+ if (reg_is_pkt_pointer_any(reg))
+ __mark_reg_unknown(reg);
}
}
@@ -1871,7 +1907,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
}
dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
dst_reg->off = ptr_reg->off;
- if (ptr_reg->type == PTR_TO_PACKET) {
+ if (reg_is_pkt_pointer(ptr_reg)) {
dst_reg->id = ++env->id_gen;
/* something was added to pkt_ptr, set range to zero */
dst_reg->range = 0;
@@ -1931,7 +1967,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
}
dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
dst_reg->off = ptr_reg->off;
- if (ptr_reg->type == PTR_TO_PACKET) {
+ if (reg_is_pkt_pointer(ptr_reg)) {
dst_reg->id = ++env->id_gen;
/* something was added to pkt_ptr, set range to zero */
if (smin_val < 0)
@@ -2421,7 +2457,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
}
static void find_good_pkt_pointers(struct bpf_verifier_state *state,
- struct bpf_reg_state *dst_reg)
+ struct bpf_reg_state *dst_reg,
+ enum bpf_reg_type type)
{
struct bpf_reg_state *regs = state->regs, *reg;
int i;
@@ -2483,7 +2520,7 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state,
* dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
*/
for (i = 0; i < MAX_BPF_REG; i++)
- if (regs[i].type == PTR_TO_PACKET && regs[i].id == dst_reg->id)
+ if (regs[i].type == type && regs[i].id == dst_reg->id)
/* keep the maximum range already checked */
regs[i].range = max_t(u16, regs[i].range, dst_reg->off);
@@ -2491,7 +2528,7 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *state,
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)
+ if (reg->type == type && reg->id == dst_reg->id)
reg->range = max_t(u16, reg->range, dst_reg->off);
}
}
@@ -2856,19 +2893,39 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT &&
dst_reg->type == PTR_TO_PACKET &&
regs[insn->src_reg].type == PTR_TO_PACKET_END) {
- find_good_pkt_pointers(this_branch, dst_reg);
+ find_good_pkt_pointers(this_branch, dst_reg, PTR_TO_PACKET);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLT &&
dst_reg->type == PTR_TO_PACKET &&
regs[insn->src_reg].type == PTR_TO_PACKET_END) {
- find_good_pkt_pointers(other_branch, dst_reg);
+ find_good_pkt_pointers(other_branch, dst_reg, PTR_TO_PACKET);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE &&
dst_reg->type == PTR_TO_PACKET_END &&
regs[insn->src_reg].type == PTR_TO_PACKET) {
- find_good_pkt_pointers(other_branch, &regs[insn->src_reg]);
+ find_good_pkt_pointers(other_branch, &regs[insn->src_reg],
+ PTR_TO_PACKET);
} else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLE &&
dst_reg->type == PTR_TO_PACKET_END &&
regs[insn->src_reg].type == PTR_TO_PACKET) {
- find_good_pkt_pointers(this_branch, &regs[insn->src_reg]);
+ find_good_pkt_pointers(this_branch, &regs[insn->src_reg],
+ PTR_TO_PACKET);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGT &&
+ dst_reg->type == PTR_TO_PACKET_META &&
+ reg_is_init_pkt_pointer(&regs[insn->src_reg], PTR_TO_PACKET)) {
+ find_good_pkt_pointers(this_branch, dst_reg, PTR_TO_PACKET_META);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLT &&
+ dst_reg->type == PTR_TO_PACKET_META &&
+ reg_is_init_pkt_pointer(&regs[insn->src_reg], PTR_TO_PACKET)) {
+ find_good_pkt_pointers(other_branch, dst_reg, PTR_TO_PACKET_META);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JGE &&
+ reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+ regs[insn->src_reg].type == PTR_TO_PACKET_META) {
+ find_good_pkt_pointers(other_branch, &regs[insn->src_reg],
+ PTR_TO_PACKET_META);
+ } else if (BPF_SRC(insn->code) == BPF_X && opcode == BPF_JLE &&
+ reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+ regs[insn->src_reg].type == PTR_TO_PACKET_META) {
+ find_good_pkt_pointers(this_branch, &regs[insn->src_reg],
+ PTR_TO_PACKET_META);
} else if (is_pointer_value(env, insn->dst_reg)) {
verbose("R%d pointer comparison prohibited\n", insn->dst_reg);
return -EACCES;
@@ -3298,8 +3355,9 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
return false;
/* Check our ids match any regs they're supposed to */
return check_ids(rold->id, rcur->id, idmap);
+ case PTR_TO_PACKET_META:
case PTR_TO_PACKET:
- if (rcur->type != PTR_TO_PACKET)
+ if (rcur->type != rold->type)
return false;
/* We must have at least as much range as the old ptr
* did, so that any accesses which were safe before are
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-18 12:32:57 +0000