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-rw-r--r--include/linux/bpf.h6
-rw-r--r--include/linux/bpf_verifier.h4
-rw-r--r--include/uapi/linux/bpf.h13
-rw-r--r--kernel/bpf/arraymap.c32
-rw-r--r--kernel/bpf/core.c3
-rw-r--r--kernel/bpf/disasm.c5
-rw-r--r--kernel/bpf/syscall.c28
-rw-r--r--kernel/bpf/verifier.c86
-rw-r--r--tools/bpf/bpftool/xlated_dumper.c3
9 files changed, 149 insertions, 31 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index a445194b5fb6..bd93a592dd29 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -57,6 +57,12 @@ struct bpf_map_ops {
const struct btf *btf,
const struct btf_type *key_type,
const struct btf_type *value_type);
+
+ /* Direct value access helpers. */
+ int (*map_direct_value_addr)(const struct bpf_map *map,
+ u64 *imm, u32 off);
+ int (*map_direct_value_meta)(const struct bpf_map *map,
+ u64 imm, u32 *off);
};
struct bpf_map {
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index fc8254d6b569..b3ab61fe1932 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -224,6 +224,10 @@ struct bpf_insn_aux_data {
unsigned long map_state; /* pointer/poison value for maps */
s32 call_imm; /* saved imm field of call insn */
u32 alu_limit; /* limit for add/sub register with pointer */
+ struct {
+ u32 map_index; /* index into used_maps[] */
+ u32 map_off; /* offset from value base address */
+ };
};
int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
int sanitize_stack_off; /* stack slot to be cleared */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 837024512baf..26cfb5b2c964 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -255,8 +255,19 @@ enum bpf_attach_type {
*/
#define BPF_F_ANY_ALIGNMENT (1U << 1)
-/* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
+/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
+ * two extensions:
+ *
+ * insn[0].src_reg: BPF_PSEUDO_MAP_FD BPF_PSEUDO_MAP_VALUE
+ * insn[0].imm: map fd map fd
+ * insn[1].imm: 0 offset into value
+ * insn[0].off: 0 0
+ * insn[1].off: 0 0
+ * ldimm64 rewrite: address of map address of map[0]+offset
+ * verifier type: CONST_PTR_TO_MAP PTR_TO_MAP_VALUE
+ */
#define BPF_PSEUDO_MAP_FD 1
+#define BPF_PSEUDO_MAP_VALUE 2
/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
* offset to another bpf function
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index c72e0d8e1e65..1a6e9861d554 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -160,6 +160,36 @@ static void *array_map_lookup_elem(struct bpf_map *map, void *key)
return array->value + array->elem_size * (index & array->index_mask);
}
+static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm,
+ u32 off)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+
+ if (map->max_entries != 1)
+ return -ENOTSUPP;
+ if (off >= map->value_size)
+ return -EINVAL;
+
+ *imm = (unsigned long)array->value;
+ return 0;
+}
+
+static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm,
+ u32 *off)
+{
+ struct bpf_array *array = container_of(map, struct bpf_array, map);
+ u64 base = (unsigned long)array->value;
+ u64 range = array->elem_size;
+
+ if (map->max_entries != 1)
+ return -ENOTSUPP;
+ if (imm < base || imm >= base + range)
+ return -ENOENT;
+
+ *off = imm - base;
+ return 0;
+}
+
/* emit BPF instructions equivalent to C code of array_map_lookup_elem() */
static u32 array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf)
{
@@ -419,6 +449,8 @@ const struct bpf_map_ops array_map_ops = {
.map_update_elem = array_map_update_elem,
.map_delete_elem = array_map_delete_elem,
.map_gen_lookup = array_map_gen_lookup,
+ .map_direct_value_addr = array_map_direct_value_addr,
+ .map_direct_value_meta = array_map_direct_value_meta,
.map_seq_show_elem = array_map_seq_show_elem,
.map_check_btf = array_map_check_btf,
};
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 2966cb368bf4..ace8c22c8b0e 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -292,7 +292,8 @@ int bpf_prog_calc_tag(struct bpf_prog *fp)
dst[i] = fp->insnsi[i];
if (!was_ld_map &&
dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
- dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
+ (dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
+ dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
was_ld_map = true;
dst[i].imm = 0;
} else if (was_ld_map &&
diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c
index de73f55e42fd..d9ce383c0f9c 100644
--- a/kernel/bpf/disasm.c
+++ b/kernel/bpf/disasm.c
@@ -205,10 +205,11 @@ void print_bpf_insn(const struct bpf_insn_cbs *cbs,
* part of the ldimm64 insn is accessible.
*/
u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
- bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD;
+ bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
+ insn->src_reg == BPF_PSEUDO_MAP_VALUE;
char tmp[64];
- if (map_ptr && !allow_ptr_leaks)
+ if (is_ptr && !allow_ptr_leaks)
imm = 0;
verbose(cbs->private_data, "(%02x) r%d = %s\n",
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 1d65e56594db..828518bb947b 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2072,13 +2072,26 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr)
}
static const struct bpf_map *bpf_map_from_imm(const struct bpf_prog *prog,
- unsigned long addr)
+ unsigned long addr, u32 *off,
+ u32 *type)
{
+ const struct bpf_map *map;
int i;
- for (i = 0; i < prog->aux->used_map_cnt; i++)
- if (prog->aux->used_maps[i] == (void *)addr)
- return prog->aux->used_maps[i];
+ for (i = 0, *off = 0; i < prog->aux->used_map_cnt; i++) {
+ map = prog->aux->used_maps[i];
+ if (map == (void *)addr) {
+ *type = BPF_PSEUDO_MAP_FD;
+ return map;
+ }
+ if (!map->ops->map_direct_value_meta)
+ continue;
+ if (!map->ops->map_direct_value_meta(map, addr, off)) {
+ *type = BPF_PSEUDO_MAP_VALUE;
+ return map;
+ }
+ }
+
return NULL;
}
@@ -2086,6 +2099,7 @@ static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog)
{
const struct bpf_map *map;
struct bpf_insn *insns;
+ u32 off, type;
u64 imm;
int i;
@@ -2113,11 +2127,11 @@ static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog)
continue;
imm = ((u64)insns[i + 1].imm << 32) | (u32)insns[i].imm;
- map = bpf_map_from_imm(prog, imm);
+ map = bpf_map_from_imm(prog, imm, &off, &type);
if (map) {
- insns[i].src_reg = BPF_PSEUDO_MAP_FD;
+ insns[i].src_reg = type;
insns[i].imm = map->id;
- insns[i + 1].imm = 0;
+ insns[i + 1].imm = off;
continue;
}
}
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 48718e1da16d..6ab7a23fc924 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5056,18 +5056,12 @@ static int check_cond_jmp_op(struct bpf_verifier_env *env,
return 0;
}
-/* return the map pointer stored inside BPF_LD_IMM64 instruction */
-static struct bpf_map *ld_imm64_to_map_ptr(struct bpf_insn *insn)
-{
- u64 imm64 = ((u64) (u32) insn[0].imm) | ((u64) (u32) insn[1].imm) << 32;
-
- return (struct bpf_map *) (unsigned long) imm64;
-}
-
/* verify BPF_LD_IMM64 instruction */
static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
{
+ struct bpf_insn_aux_data *aux = cur_aux(env);
struct bpf_reg_state *regs = cur_regs(env);
+ struct bpf_map *map;
int err;
if (BPF_SIZE(insn->code) != BPF_DW) {
@@ -5091,11 +5085,22 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
return 0;
}
- /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */
- BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD);
+ map = env->used_maps[aux->map_index];
+ mark_reg_known_zero(env, regs, insn->dst_reg);
+ regs[insn->dst_reg].map_ptr = map;
+
+ if (insn->src_reg == BPF_PSEUDO_MAP_VALUE) {
+ regs[insn->dst_reg].type = PTR_TO_MAP_VALUE;
+ regs[insn->dst_reg].off = aux->map_off;
+ if (map_value_has_spin_lock(map))
+ regs[insn->dst_reg].id = ++env->id_gen;
+ } else if (insn->src_reg == BPF_PSEUDO_MAP_FD) {
+ regs[insn->dst_reg].type = CONST_PTR_TO_MAP;
+ } else {
+ verbose(env, "bpf verifier is misconfigured\n");
+ return -EINVAL;
+ }
- regs[insn->dst_reg].type = CONST_PTR_TO_MAP;
- regs[insn->dst_reg].map_ptr = ld_imm64_to_map_ptr(insn);
return 0;
}
@@ -6803,8 +6808,10 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
}
if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
+ struct bpf_insn_aux_data *aux;
struct bpf_map *map;
struct fd f;
+ u64 addr;
if (i == insn_cnt - 1 || insn[1].code != 0 ||
insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
@@ -6813,13 +6820,19 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
return -EINVAL;
}
- if (insn->src_reg == 0)
+ if (insn[0].src_reg == 0)
/* valid generic load 64-bit imm */
goto next_insn;
- if (insn[0].src_reg != BPF_PSEUDO_MAP_FD ||
- insn[1].imm != 0) {
- verbose(env, "unrecognized bpf_ld_imm64 insn\n");
+ /* In final convert_pseudo_ld_imm64() step, this is
+ * converted into regular 64-bit imm load insn.
+ */
+ if ((insn[0].src_reg != BPF_PSEUDO_MAP_FD &&
+ insn[0].src_reg != BPF_PSEUDO_MAP_VALUE) ||
+ (insn[0].src_reg == BPF_PSEUDO_MAP_FD &&
+ insn[1].imm != 0)) {
+ verbose(env,
+ "unrecognized bpf_ld_imm64 insn\n");
return -EINVAL;
}
@@ -6837,16 +6850,47 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
return err;
}
- /* store map pointer inside BPF_LD_IMM64 instruction */
- insn[0].imm = (u32) (unsigned long) map;
- insn[1].imm = ((u64) (unsigned long) map) >> 32;
+ aux = &env->insn_aux_data[i];
+ if (insn->src_reg == BPF_PSEUDO_MAP_FD) {
+ addr = (unsigned long)map;
+ } else {
+ u32 off = insn[1].imm;
+
+ if (off >= BPF_MAX_VAR_OFF) {
+ verbose(env, "direct value offset of %u is not allowed\n", off);
+ fdput(f);
+ return -EINVAL;
+ }
+
+ if (!map->ops->map_direct_value_addr) {
+ verbose(env, "no direct value access support for this map type\n");
+ fdput(f);
+ return -EINVAL;
+ }
+
+ err = map->ops->map_direct_value_addr(map, &addr, off);
+ if (err) {
+ verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
+ map->value_size, off);
+ fdput(f);
+ return err;
+ }
+
+ aux->map_off = off;
+ addr += off;
+ }
+
+ insn[0].imm = (u32)addr;
+ insn[1].imm = addr >> 32;
/* check whether we recorded this map already */
- for (j = 0; j < env->used_map_cnt; j++)
+ for (j = 0; j < env->used_map_cnt; j++) {
if (env->used_maps[j] == map) {
+ aux->map_index = j;
fdput(f);
goto next_insn;
}
+ }
if (env->used_map_cnt >= MAX_USED_MAPS) {
fdput(f);
@@ -6863,6 +6907,8 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
fdput(f);
return PTR_ERR(map);
}
+
+ aux->map_index = env->used_map_cnt;
env->used_maps[env->used_map_cnt++] = map;
if (bpf_map_is_cgroup_storage(map) &&
diff --git a/tools/bpf/bpftool/xlated_dumper.c b/tools/bpf/bpftool/xlated_dumper.c
index 7073dbe1ff27..0bb17bf88b18 100644
--- a/tools/bpf/bpftool/xlated_dumper.c
+++ b/tools/bpf/bpftool/xlated_dumper.c
@@ -195,6 +195,9 @@ static const char *print_imm(void *private_data,
if (insn->src_reg == BPF_PSEUDO_MAP_FD)
snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
"map[id:%u]", insn->imm);
+ else if (insn->src_reg == BPF_PSEUDO_MAP_VALUE)
+ snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
+ "map[id:%u][0]+%u", insn->imm, (insn + 1)->imm);
else
snprintf(dd->scratch_buff, sizeof(dd->scratch_buff),
"0x%llx", (unsigned long long)full_imm);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 23:10:32 +0000