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bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL

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We have introduced a new type to make bpf_reg composable, by
allocating bits in the type to represent flags.

One of the flags is PTR_MAYBE_NULL which indicates a pointer
may be NULL. This patch switches the qualified reg_types to
use this flag. The reg_types changed in this patch include:

1. PTR_TO_MAP_VALUE_OR_NULL
2. PTR_TO_SOCKET_OR_NULL
3. PTR_TO_SOCK_COMMON_OR_NULL
4. PTR_TO_TCP_SOCK_OR_NULL
5. PTR_TO_BTF_ID_OR_NULL
6. PTR_TO_MEM_OR_NULL
7. PTR_TO_RDONLY_BUF_OR_NULL
8. PTR_TO_RDWR_BUF_OR_NULL

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211217003152.48334-5-haoluo@google.com
This commit is contained in:
Hao Luo 2021-12-16 16:31:47 -08:00 committed by Alexei Starovoitov
parent 3c48073226
commit c25b2ae136
7 changed files with 147 additions and 188 deletions
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18
include/linux/bpf.h
View File

@ -465,18 +465,15 @@ enum bpf_reg_type {
PTR_TO_CTX, /* reg points to bpf_context */
CONST_PTR_TO_MAP, /* reg points to struct bpf_map */
PTR_TO_MAP_VALUE, /* reg points to map element value */
PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */
PTR_TO_MAP_KEY, /* reg points to a map element key */
PTR_TO_STACK, /* reg == frame_pointer + offset */
PTR_TO_PACKET_META, /* skb->data - meta_len */
PTR_TO_PACKET, /* reg points to skb->data */
PTR_TO_PACKET_END, /* skb->data + headlen */
PTR_TO_FLOW_KEYS, /* reg points to bpf_flow_keys */
PTR_TO_SOCKET, /* reg points to struct bpf_sock */
PTR_TO_SOCKET_OR_NULL, /* reg points to struct bpf_sock or NULL */
PTR_TO_SOCK_COMMON, /* reg points to sock_common */
PTR_TO_SOCK_COMMON_OR_NULL, /* reg points to sock_common or NULL */
PTR_TO_TCP_SOCK, /* reg points to struct tcp_sock */
PTR_TO_TCP_SOCK_OR_NULL, /* reg points to struct tcp_sock or NULL */
PTR_TO_TP_BUFFER, /* reg points to a writable raw tp's buffer */
PTR_TO_XDP_SOCK, /* reg points to struct xdp_sock */
/* PTR_TO_BTF_ID points to a kernel struct that does not need
@ -494,18 +491,21 @@ enum bpf_reg_type {
* been checked for null. Used primarily to inform the verifier
* an explicit null check is required for this struct.
*/
PTR_TO_BTF_ID_OR_NULL,
PTR_TO_MEM, /* reg points to valid memory region */
PTR_TO_MEM_OR_NULL, /* reg points to valid memory region or NULL */
PTR_TO_RDONLY_BUF, /* reg points to a readonly buffer */
PTR_TO_RDONLY_BUF_OR_NULL, /* reg points to a readonly buffer or NULL */
PTR_TO_RDWR_BUF, /* reg points to a read/write buffer */
PTR_TO_RDWR_BUF_OR_NULL, /* reg points to a read/write buffer or NULL */
PTR_TO_PERCPU_BTF_ID, /* reg points to a percpu kernel variable */
PTR_TO_FUNC, /* reg points to a bpf program function */
PTR_TO_MAP_KEY, /* reg points to a map element key */
__BPF_REG_TYPE_MAX,
/* Extended reg_types. */
PTR_TO_MAP_VALUE_OR_NULL = PTR_MAYBE_NULL | PTR_TO_MAP_VALUE,
PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | PTR_TO_SOCKET,
PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | PTR_TO_SOCK_COMMON,
PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | PTR_TO_TCP_SOCK,
PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | PTR_TO_BTF_ID,
PTR_TO_MEM_OR_NULL = PTR_MAYBE_NULL | PTR_TO_MEM,
/* This must be the last entry. Its purpose is to ensure the enum is
* wide enough to hold the higher bits reserved for bpf_type_flag.
*/

4
include/linux/bpf_verifier.h
View File

@ -18,6 +18,8 @@
* that converting umax_value to int cannot overflow.
*/
#define BPF_MAX_VAR_SIZ (1 << 29)
/* size of type_str_buf in bpf_verifier. */
#define TYPE_STR_BUF_LEN 64
/* Liveness marks, used for registers and spilled-regs (in stack slots).
* Read marks propagate upwards until they find a write mark; they record that
@ -484,6 +486,8 @@ struct bpf_verifier_env {
/* Same as scratched_regs but for stack slots */
u64 scratched_stack_slots;
u32 prev_log_len, prev_insn_print_len;
/* buffer used in reg_type_str() to generate reg_type string */
char type_str_buf[TYPE_STR_BUF_LEN];
};
__printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log,

7
kernel/bpf/btf.c
View File

@ -4940,10 +4940,13 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
/* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
u32 type, flag;
type = base_type(ctx_arg_info->reg_type);
flag = type_flag(ctx_arg_info->reg_type);
if (ctx_arg_info->offset == off &&
(ctx_arg_info->reg_type == PTR_TO_RDONLY_BUF_OR_NULL ||
ctx_arg_info->reg_type == PTR_TO_RDWR_BUF_OR_NULL)) {
(type == PTR_TO_RDWR_BUF || type == PTR_TO_RDONLY_BUF) &&
(flag & PTR_MAYBE_NULL)) {
info->reg_type = ctx_arg_info->reg_type;
return true;
}

4
kernel/bpf/map_iter.c
View File

@ -174,9 +174,9 @@ static const struct bpf_iter_reg bpf_map_elem_reg_info = {
.ctx_arg_info_size = 2,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__bpf_map_elem, key),
PTR_TO_RDONLY_BUF_OR_NULL },
PTR_TO_RDONLY_BUF | PTR_MAYBE_NULL },
{ offsetof(struct bpf_iter__bpf_map_elem, value),
PTR_TO_RDWR_BUF_OR_NULL },
PTR_TO_RDWR_BUF | PTR_MAYBE_NULL },
},
};

298
kernel/bpf/verifier.c
View File

@ -442,18 +442,6 @@ static bool reg_type_not_null(enum bpf_reg_type type)
type == PTR_TO_SOCK_COMMON;
}
static bool reg_type_may_be_null(enum bpf_reg_type type)
{
return type == PTR_TO_MAP_VALUE_OR_NULL ||
type == PTR_TO_SOCKET_OR_NULL ||
type == PTR_TO_SOCK_COMMON_OR_NULL ||
type == PTR_TO_TCP_SOCK_OR_NULL ||
type == PTR_TO_BTF_ID_OR_NULL ||
type == PTR_TO_MEM_OR_NULL ||
type == PTR_TO_RDONLY_BUF_OR_NULL ||
type == PTR_TO_RDWR_BUF_OR_NULL;
}
static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
{
return reg->type == PTR_TO_MAP_VALUE &&
@ -462,12 +450,9 @@ static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
{
return type == PTR_TO_SOCKET ||
type == PTR_TO_SOCKET_OR_NULL ||
type == PTR_TO_TCP_SOCK ||
type == PTR_TO_TCP_SOCK_OR_NULL ||
type == PTR_TO_MEM ||
type == PTR_TO_MEM_OR_NULL;
return base_type(type) == PTR_TO_SOCKET ||
base_type(type) == PTR_TO_TCP_SOCK ||
base_type(type) == PTR_TO_MEM;
}
static bool arg_type_may_be_refcounted(enum bpf_arg_type type)
@ -537,39 +522,52 @@ static bool is_cmpxchg_insn(const struct bpf_insn *insn)
insn->imm == BPF_CMPXCHG;
}
/* string representation of 'enum bpf_reg_type' */
static const char * const reg_type_str[] = {
[NOT_INIT] = "?",
[SCALAR_VALUE] = "inv",
[PTR_TO_CTX] = "ctx",
[CONST_PTR_TO_MAP] = "map_ptr",
[PTR_TO_MAP_VALUE] = "map_value",
[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",
[PTR_TO_FLOW_KEYS] = "flow_keys",
[PTR_TO_SOCKET] = "sock",
[PTR_TO_SOCKET_OR_NULL] = "sock_or_null",
[PTR_TO_SOCK_COMMON] = "sock_common",
[PTR_TO_SOCK_COMMON_OR_NULL] = "sock_common_or_null",
[PTR_TO_TCP_SOCK] = "tcp_sock",
[PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null",
[PTR_TO_TP_BUFFER] = "tp_buffer",
[PTR_TO_XDP_SOCK] = "xdp_sock",
[PTR_TO_BTF_ID] = "ptr_",
[PTR_TO_BTF_ID_OR_NULL] = "ptr_or_null_",
[PTR_TO_PERCPU_BTF_ID] = "percpu_ptr_",
[PTR_TO_MEM] = "mem",
[PTR_TO_MEM_OR_NULL] = "mem_or_null",
[PTR_TO_RDONLY_BUF] = "rdonly_buf",
[PTR_TO_RDONLY_BUF_OR_NULL] = "rdonly_buf_or_null",
[PTR_TO_RDWR_BUF] = "rdwr_buf",
[PTR_TO_RDWR_BUF_OR_NULL] = "rdwr_buf_or_null",
[PTR_TO_FUNC] = "func",
[PTR_TO_MAP_KEY] = "map_key",
};
/* string representation of 'enum bpf_reg_type'
*
* Note that reg_type_str() can not appear more than once in a single verbose()
* statement.
*/
static const char *reg_type_str(struct bpf_verifier_env *env,
enum bpf_reg_type type)
{
char postfix[16] = {0};
static const char * const str[] = {
[NOT_INIT] = "?",
[SCALAR_VALUE] = "inv",
[PTR_TO_CTX] = "ctx",
[CONST_PTR_TO_MAP] = "map_ptr",
[PTR_TO_MAP_VALUE] = "map_value",
[PTR_TO_STACK] = "fp",
[PTR_TO_PACKET] = "pkt",
[PTR_TO_PACKET_META] = "pkt_meta",
[PTR_TO_PACKET_END] = "pkt_end",
[PTR_TO_FLOW_KEYS] = "flow_keys",
[PTR_TO_SOCKET] = "sock",
[PTR_TO_SOCK_COMMON] = "sock_common",
[PTR_TO_TCP_SOCK] = "tcp_sock",
[PTR_TO_TP_BUFFER] = "tp_buffer",
[PTR_TO_XDP_SOCK] = "xdp_sock",
[PTR_TO_BTF_ID] = "ptr_",
[PTR_TO_PERCPU_BTF_ID] = "percpu_ptr_",
[PTR_TO_MEM] = "mem",
[PTR_TO_RDONLY_BUF] = "rdonly_buf",
[PTR_TO_RDWR_BUF] = "rdwr_buf",
[PTR_TO_FUNC] = "func",
[PTR_TO_MAP_KEY] = "map_key",
};
if (type & PTR_MAYBE_NULL) {
if (base_type(type) == PTR_TO_BTF_ID ||
base_type(type) == PTR_TO_PERCPU_BTF_ID)
strncpy(postfix, "or_null_", 16);
else
strncpy(postfix, "_or_null", 16);
}
snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s",
str[base_type(type)], postfix);
return env->type_str_buf;
}
static char slot_type_char[] = {
[STACK_INVALID] = '?',
@ -675,7 +673,7 @@ static void print_verifier_state(struct bpf_verifier_env *env,
continue;
verbose(env, " R%d", i);
print_liveness(env, reg->live);
verbose(env, "=%s", reg_type_str[t]);
verbose(env, "=%s", reg_type_str(env, t));
if (t == SCALAR_VALUE && reg->precise)
verbose(env, "P");
if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
@ -683,9 +681,8 @@ static void print_verifier_state(struct bpf_verifier_env *env,
/* reg->off should be 0 for SCALAR_VALUE */
verbose(env, "%lld", reg->var_off.value + reg->off);
} else {
if (t == PTR_TO_BTF_ID ||
t == PTR_TO_BTF_ID_OR_NULL ||
t == PTR_TO_PERCPU_BTF_ID)
if (base_type(t) == PTR_TO_BTF_ID ||
base_type(t) == PTR_TO_PERCPU_BTF_ID)
verbose(env, "%s", kernel_type_name(reg->btf, reg->btf_id));
verbose(env, "(id=%d", reg->id);
if (reg_type_may_be_refcounted_or_null(t))
@ -694,10 +691,9 @@ static void print_verifier_state(struct bpf_verifier_env *env,
verbose(env, ",off=%d", reg->off);
if (type_is_pkt_pointer(t))
verbose(env, ",r=%d", reg->range);
else if (t == CONST_PTR_TO_MAP ||
t == PTR_TO_MAP_KEY ||
t == PTR_TO_MAP_VALUE ||
t == PTR_TO_MAP_VALUE_OR_NULL)
else if (base_type(t) == CONST_PTR_TO_MAP ||
base_type(t) == PTR_TO_MAP_KEY ||
base_type(t) == PTR_TO_MAP_VALUE)
verbose(env, ",ks=%d,vs=%d",
reg->map_ptr->key_size,
reg->map_ptr->value_size);
@ -769,7 +765,7 @@ static void print_verifier_state(struct bpf_verifier_env *env,
if (is_spilled_reg(&state->stack[i])) {
reg = &state->stack[i].spilled_ptr;
t = reg->type;
verbose(env, "=%s", reg_type_str[t]);
verbose(env, "=%s", reg_type_str(env, t));
if (t == SCALAR_VALUE && reg->precise)
verbose(env, "P");
if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
@ -1202,8 +1198,7 @@ static void mark_reg_known_zero(struct bpf_verifier_env *env,
static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
{
switch (reg->type) {
case PTR_TO_MAP_VALUE_OR_NULL: {
if (base_type(reg->type) == PTR_TO_MAP_VALUE) {
const struct bpf_map *map = reg->map_ptr;
if (map->inner_map_meta) {
@ -1222,32 +1217,10 @@ static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
} else {
reg->type = PTR_TO_MAP_VALUE;
}
break;
}
case PTR_TO_SOCKET_OR_NULL:
reg->type = PTR_TO_SOCKET;
break;
case PTR_TO_SOCK_COMMON_OR_NULL:
reg->type = PTR_TO_SOCK_COMMON;
break;
case PTR_TO_TCP_SOCK_OR_NULL:
reg->type = PTR_TO_TCP_SOCK;
break;
case PTR_TO_BTF_ID_OR_NULL:
reg->type = PTR_TO_BTF_ID;
break;
case PTR_TO_MEM_OR_NULL:
reg->type = PTR_TO_MEM;
break;
case PTR_TO_RDONLY_BUF_OR_NULL:
reg->type = PTR_TO_RDONLY_BUF;
break;
case PTR_TO_RDWR_BUF_OR_NULL:
reg->type = PTR_TO_RDWR_BUF;
break;
default:
WARN_ONCE(1, "unknown nullable register type");
return;
}
reg->type &= ~PTR_MAYBE_NULL;
}
static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
@ -2103,7 +2076,7 @@ static int mark_reg_read(struct bpf_verifier_env *env,
break;
if (parent->live & REG_LIVE_DONE) {
verbose(env, "verifier BUG type %s var_off %lld off %d\n",
reg_type_str[parent->type],
reg_type_str(env, parent->type),
parent->var_off.value, parent->off);
return -EFAULT;
}
@ -2768,9 +2741,8 @@ static int mark_chain_precision_stack(struct bpf_verifier_env *env, int spi)
static bool is_spillable_regtype(enum bpf_reg_type type)
{
switch (type) {
switch (base_type(type)) {
case PTR_TO_MAP_VALUE:
case PTR_TO_MAP_VALUE_OR_NULL:
case PTR_TO_STACK:
case PTR_TO_CTX:
case PTR_TO_PACKET:
@ -2779,21 +2751,14 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
case PTR_TO_FLOW_KEYS:
case CONST_PTR_TO_MAP:
case PTR_TO_SOCKET:
case PTR_TO_SOCKET_OR_NULL:
case PTR_TO_SOCK_COMMON:
case PTR_TO_SOCK_COMMON_OR_NULL:
case PTR_TO_TCP_SOCK:
case PTR_TO_TCP_SOCK_OR_NULL:
case PTR_TO_XDP_SOCK:
case PTR_TO_BTF_ID:
case PTR_TO_BTF_ID_OR_NULL:
case PTR_TO_RDONLY_BUF:
case PTR_TO_RDONLY_BUF_OR_NULL:
case PTR_TO_RDWR_BUF:
case PTR_TO_RDWR_BUF_OR_NULL:
case PTR_TO_PERCPU_BTF_ID:
case PTR_TO_MEM:
case PTR_TO_MEM_OR_NULL:
case PTR_TO_FUNC:
case PTR_TO_MAP_KEY:
return true;
@ -3633,7 +3598,7 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off,
*/
*reg_type = info.reg_type;
if (*reg_type == PTR_TO_BTF_ID || *reg_type == PTR_TO_BTF_ID_OR_NULL) {
if (base_type(*reg_type) == PTR_TO_BTF_ID) {
*btf = info.btf;
*btf_id = info.btf_id;
} else {
@ -3701,7 +3666,7 @@ static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
}
verbose(env, "R%d invalid %s access off=%d size=%d\n",
regno, reg_type_str[reg->type], off, size);
regno, reg_type_str(env, reg->type), off, size);
return -EACCES;
}
@ -4466,7 +4431,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
} else {
mark_reg_known_zero(env, regs,
value_regno);
if (reg_type_may_be_null(reg_type))
if (type_may_be_null(reg_type))
regs[value_regno].id = ++env->id_gen;
/* A load of ctx field could have different
* actual load size with the one encoded in the
@ -4474,8 +4439,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
* a sub-register.
*/
regs[value_regno].subreg_def = DEF_NOT_SUBREG;
if (reg_type == PTR_TO_BTF_ID ||
reg_type == PTR_TO_BTF_ID_OR_NULL) {
if (base_type(reg_type) == PTR_TO_BTF_ID) {
regs[value_regno].btf = btf;
regs[value_regno].btf_id = btf_id;
}
@ -4528,7 +4492,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
} else if (type_is_sk_pointer(reg->type)) {
if (t == BPF_WRITE) {
verbose(env, "R%d cannot write into %s\n",
regno, reg_type_str[reg->type]);
regno, reg_type_str(env, reg->type));
return -EACCES;
}
err = check_sock_access(env, insn_idx, regno, off, size, t);
@ -4547,7 +4511,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
} else if (reg->type == PTR_TO_RDONLY_BUF) {
if (t == BPF_WRITE) {
verbose(env, "R%d cannot write into %s\n",
regno, reg_type_str[reg->type]);
regno, reg_type_str(env, reg->type));
return -EACCES;
}
err = check_buffer_access(env, reg, regno, off, size, false,
@ -4563,7 +4527,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
mark_reg_unknown(env, regs, value_regno);
} else {
verbose(env, "R%d invalid mem access '%s'\n", regno,
reg_type_str[reg->type]);
reg_type_str(env, reg->type));
return -EACCES;
}
@ -4630,7 +4594,7 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i
is_sk_reg(env, insn->dst_reg)) {
verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
insn->dst_reg,
reg_type_str[reg_state(env, insn->dst_reg)->type]);
reg_type_str(env, reg_state(env, insn->dst_reg)->type));
return -EACCES;
}
@ -4850,9 +4814,9 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
register_is_null(reg))
return 0;
verbose(env, "R%d type=%s expected=%s\n", regno,
reg_type_str[reg->type],
reg_type_str[PTR_TO_STACK]);
verbose(env, "R%d type=%s ", regno,
reg_type_str(env, reg->type));
verbose(env, "expected=%s\n", reg_type_str(env, PTR_TO_STACK));
return -EACCES;
}
}
@ -4863,7 +4827,7 @@ int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
if (register_is_null(reg))
return 0;
if (reg_type_may_be_null(reg->type)) {
if (type_may_be_null(reg->type)) {
/* Assuming that the register contains a value check if the memory
* access is safe. Temporarily save and restore the register's state as
* the conversion shouldn't be visible to a caller.
@ -5197,10 +5161,10 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
goto found;
}
verbose(env, "R%d type=%s expected=", regno, reg_type_str[type]);
verbose(env, "R%d type=%s expected=", regno, reg_type_str(env, type));
for (j = 0; j + 1 < i; j++)
verbose(env, "%s, ", reg_type_str[compatible->types[j]]);
verbose(env, "%s\n", reg_type_str[compatible->types[j]]);
verbose(env, "%s, ", reg_type_str(env, compatible->types[j]));
verbose(env, "%s\n", reg_type_str(env, compatible->types[j]));
return -EACCES;
found:
@ -6474,6 +6438,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
{
const struct bpf_func_proto *fn = NULL;
enum bpf_return_type ret_type;
enum bpf_type_flag ret_flag;
struct bpf_reg_state *regs;
struct bpf_call_arg_meta meta;
int insn_idx = *insn_idx_p;
@ -6614,6 +6579,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
/* update return register (already marked as written above) */
ret_type = fn->ret_type;
ret_flag = type_flag(fn->ret_type);
if (ret_type == RET_INTEGER) {
/* sets type to SCALAR_VALUE */
mark_reg_unknown(env, regs, BPF_REG_0);
@ -6633,25 +6599,23 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
}
regs[BPF_REG_0].map_ptr = meta.map_ptr;
regs[BPF_REG_0].map_uid = meta.map_uid;
if (type_may_be_null(ret_type)) {
regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
} else {
regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
if (map_value_has_spin_lock(meta.map_ptr))
regs[BPF_REG_0].id = ++env->id_gen;
regs[BPF_REG_0].type = PTR_TO_MAP_VALUE | ret_flag;
if (!type_may_be_null(ret_type) &&
map_value_has_spin_lock(meta.map_ptr)) {
regs[BPF_REG_0].id = ++env->id_gen;
}
} else if (base_type(ret_type) == RET_PTR_TO_SOCKET) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_SOCKET_OR_NULL;
regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
} else if (base_type(ret_type) == RET_PTR_TO_SOCK_COMMON) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON_OR_NULL;
regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
} else if (base_type(ret_type) == RET_PTR_TO_TCP_SOCK) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_TCP_SOCK_OR_NULL;
regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
} else if (base_type(ret_type) == RET_PTR_TO_ALLOC_MEM) {
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_MEM_OR_NULL;
regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
regs[BPF_REG_0].mem_size = meta.mem_size;
} else if (base_type(ret_type) == RET_PTR_TO_MEM_OR_BTF_ID) {
const struct btf_type *t;
@ -6671,14 +6635,10 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
tname, PTR_ERR(ret));
return -EINVAL;
}
regs[BPF_REG_0].type =
(ret_type & PTR_MAYBE_NULL) ?
PTR_TO_MEM_OR_NULL : PTR_TO_MEM;
regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
regs[BPF_REG_0].mem_size = tsize;
} else {
regs[BPF_REG_0].type =
(ret_type & PTR_MAYBE_NULL) ?
PTR_TO_BTF_ID_OR_NULL : PTR_TO_BTF_ID;
regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
regs[BPF_REG_0].btf = meta.ret_btf;
regs[BPF_REG_0].btf_id = meta.ret_btf_id;
}
@ -6686,9 +6646,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
int ret_btf_id;
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = (ret_type & PTR_MAYBE_NULL) ?
PTR_TO_BTF_ID_OR_NULL :
PTR_TO_BTF_ID;
regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
ret_btf_id = *fn->ret_btf_id;
if (ret_btf_id == 0) {
verbose(env, "invalid return type %u of func %s#%d\n",
@ -6707,7 +6665,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
return -EINVAL;
}
if (reg_type_may_be_null(regs[BPF_REG_0].type))
if (type_may_be_null(regs[BPF_REG_0].type))
regs[BPF_REG_0].id = ++env->id_gen;
if (is_ptr_cast_function(func_id)) {
@ -6916,25 +6874,25 @@ static bool check_reg_sane_offset(struct bpf_verifier_env *env,
if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) {
verbose(env, "math between %s pointer and %lld is not allowed\n",
reg_type_str[type], val);
reg_type_str(env, type), val);
return false;
}
if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) {
verbose(env, "%s pointer offset %d is not allowed\n",
reg_type_str[type], reg->off);
reg_type_str(env, type), reg->off);
return false;
}
if (smin == S64_MIN) {
verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n",
reg_type_str[type]);
reg_type_str(env, type));
return false;
}
if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
verbose(env, "value %lld makes %s pointer be out of bounds\n",
smin, reg_type_str[type]);
smin, reg_type_str(env, type));
return false;
}
@ -7311,11 +7269,13 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
return -EACCES;
}
switch (ptr_reg->type) {
case PTR_TO_MAP_VALUE_OR_NULL:
if (ptr_reg->type & PTR_MAYBE_NULL) {
verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
dst, reg_type_str[ptr_reg->type]);
dst, reg_type_str(env, ptr_reg->type));
return -EACCES;
}
switch (base_type(ptr_reg->type)) {
case CONST_PTR_TO_MAP:
/* smin_val represents the known value */
if (known && smin_val == 0 && opcode == BPF_ADD)
@ -7323,14 +7283,11 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
fallthrough;
case PTR_TO_PACKET_END:
case PTR_TO_SOCKET:
case PTR_TO_SOCKET_OR_NULL:
case PTR_TO_SOCK_COMMON:
case PTR_TO_SOCK_COMMON_OR_NULL:
case PTR_TO_TCP_SOCK:
case PTR_TO_TCP_SOCK_OR_NULL:
case PTR_TO_XDP_SOCK:
verbose(env, "R%d pointer arithmetic on %s prohibited\n",
dst, reg_type_str[ptr_reg->type]);
dst, reg_type_str(env, ptr_reg->type));
return -EACCES;
default:
break;
@ -9049,7 +9006,7 @@ static void mark_ptr_or_null_reg(struct bpf_func_state *state,
struct bpf_reg_state *reg, u32 id,
bool is_null)
{
if (reg_type_may_be_null(reg->type) && reg->id == id &&
if (type_may_be_null(reg->type) && reg->id == id &&
!WARN_ON_ONCE(!reg->id)) {
/* Old offset (both fixed and variable parts) should
* have been known-zero, because we don't allow pointer
@ -9427,7 +9384,7 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
*/
if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
reg_type_may_be_null(dst_reg->type)) {
type_may_be_null(dst_reg->type)) {
/* Mark all identical registers in each branch as either
* safe or unknown depending R == 0 or R != 0 conditional.
*/
@ -9681,7 +9638,7 @@ static int check_return_code(struct bpf_verifier_env *env)
/* enforce return zero from async callbacks like timer */
if (reg->type != SCALAR_VALUE) {
verbose(env, "In async callback the register R0 is not a known value (%s)\n",
reg_type_str[reg->type]);
reg_type_str(env, reg->type));
return -EINVAL;
}
@ -9695,7 +9652,7 @@ static int check_return_code(struct bpf_verifier_env *env)
if (is_subprog) {
if (reg->type != SCALAR_VALUE) {
verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n",
reg_type_str[reg->type]);
reg_type_str(env, reg->type));
return -EINVAL;
}
return 0;
@ -9759,7 +9716,7 @@ static int check_return_code(struct bpf_verifier_env *env)
if (reg->type != SCALAR_VALUE) {
verbose(env, "At program exit the register R0 is not a known value (%s)\n",
reg_type_str[reg->type]);
reg_type_str(env, reg->type));
return -EINVAL;
}
@ -10616,7 +10573,7 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
return true;
if (rcur->type == NOT_INIT)
return false;
switch (rold->type) {
switch (base_type(rold->type)) {
case SCALAR_VALUE:
if (env->explore_alu_limits)
return false;
@ -10638,6 +10595,22 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
}
case PTR_TO_MAP_KEY:
case PTR_TO_MAP_VALUE:
/* a PTR_TO_MAP_VALUE could be safe to use as a
* PTR_TO_MAP_VALUE_OR_NULL into the same map.
* However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL-
* checked, doing so could have affected others with the same
* id, and we can't check for that because we lost the id when
* we converted to a PTR_TO_MAP_VALUE.
*/
if (type_may_be_null(rold->type)) {
if (!type_may_be_null(rcur->type))
return false;
if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)))
return false;
/* Check our ids match any regs they're supposed to */
return check_ids(rold->id, rcur->id, idmap);
}
/* If the new min/max/var_off satisfy the old ones and
* everything else matches, we are OK.
* 'id' is not compared, since it's only used for maps with
@ -10649,20 +10622,6 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
range_within(rold, rcur) &&
tnum_in(rold->var_off, rcur->var_off);
case PTR_TO_MAP_VALUE_OR_NULL:
/* a PTR_TO_MAP_VALUE could be safe to use as a
* PTR_TO_MAP_VALUE_OR_NULL into the same map.
* However, if the old PTR_TO_MAP_VALUE_OR_NULL then got NULL-
* checked, doing so could have affected others with the same
* id, and we can't check for that because we lost the id when
* we converted to a PTR_TO_MAP_VALUE.
*/
if (rcur->type != PTR_TO_MAP_VALUE_OR_NULL)
return false;
if (memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)))
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 != rold->type)
@ -10691,11 +10650,8 @@ static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
case PTR_TO_PACKET_END:
case PTR_TO_FLOW_KEYS:
case PTR_TO_SOCKET:
case PTR_TO_SOCKET_OR_NULL:
case PTR_TO_SOCK_COMMON:
case PTR_TO_SOCK_COMMON_OR_NULL:
case PTR_TO_TCP_SOCK:
case PTR_TO_TCP_SOCK_OR_NULL:
case PTR_TO_XDP_SOCK:
/* Only valid matches are exact, which memcmp() above
* would have accepted
@ -11221,17 +11177,13 @@ next:
/* Return true if it's OK to have the same insn return a different type. */
static bool reg_type_mismatch_ok(enum bpf_reg_type type)
{
switch (type) {
switch (base_type(type)) {
case PTR_TO_CTX:
case PTR_TO_SOCKET:
case PTR_TO_SOCKET_OR_NULL:
case PTR_TO_SOCK_COMMON:
case PTR_TO_SOCK_COMMON_OR_NULL:
case PTR_TO_TCP_SOCK:
case PTR_TO_TCP_SOCK_OR_NULL:
case PTR_TO_XDP_SOCK:
case PTR_TO_BTF_ID:
case PTR_TO_BTF_ID_OR_NULL:
return false;
default:
return true;
@ -11457,7 +11409,7 @@ static int do_check(struct bpf_verifier_env *env)
if (is_ctx_reg(env, insn->dst_reg)) {
verbose(env, "BPF_ST stores into R%d %s is not allowed\n",
insn->dst_reg,
reg_type_str[reg_state(env, insn->dst_reg)->type]);
reg_type_str(env, reg_state(env, insn->dst_reg)->type));
return -EACCES;
}

2
net/core/bpf_sk_storage.c
View File

@ -929,7 +929,7 @@ static struct bpf_iter_reg bpf_sk_storage_map_reg_info = {
{ offsetof(struct bpf_iter__bpf_sk_storage_map, sk),
PTR_TO_BTF_ID_OR_NULL },
{ offsetof(struct bpf_iter__bpf_sk_storage_map, value),
PTR_TO_RDWR_BUF_OR_NULL },
PTR_TO_RDWR_BUF | PTR_MAYBE_NULL },
},
.seq_info = &iter_seq_info,
};

2
net/core/sock_map.c
View File

@ -1564,7 +1564,7 @@ static struct bpf_iter_reg sock_map_iter_reg = {
.ctx_arg_info_size = 2,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__sockmap, key),
PTR_TO_RDONLY_BUF_OR_NULL },
PTR_TO_RDONLY_BUF | PTR_MAYBE_NULL },
{ offsetof(struct bpf_iter__sockmap, sk),
PTR_TO_BTF_ID_OR_NULL },
},