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bpf: Move map/prog compatibility checks

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Move some inlined map/prog compatibility checks from the
resolve_pseudo_ldimm64() function to the dedicated
check_map_prog_compatibility() function. Call the latter function
from the add_used_map_from_fd() function directly.

This simplifies code and optimizes logic a bit, as before these
changes the check_map_prog_compatibility() function was executed on
every map usage, which doesn't make sense, as it doesn't include any
per-instruction checks, only map type vs. prog type.

(This patch also simplifies a consequent patch which will call the
add_used_map_from_fd() function from another code path.)

Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241213130934.1087929-3-aspsk@isovalent.com
This commit is contained in:
Anton Protopopov
2024-12-13 13:09:29 +00:00
committed by Andrii Nakryiko
parent 4e885fab71
commit 928f3221cb
1 changed files with 46 additions and 55 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/bpf/verifier.c
+46 -55
View File
@@ -19368,6 +19368,12 @@ static bool is_tracing_prog_type(enum bpf_prog_type type)
}
}
static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
{
return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
}
static int check_map_prog_compatibility(struct bpf_verifier_env *env,
struct bpf_map *map,
struct bpf_prog *prog)
@@ -19446,25 +19452,48 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,
return -EINVAL;
}
if (bpf_map_is_cgroup_storage(map) &&
bpf_cgroup_storage_assign(env->prog->aux, map)) {
verbose(env, "only one cgroup storage of each type is allowed\n");
return -EBUSY;
}
if (map->map_type == BPF_MAP_TYPE_ARENA) {
if (env->prog->aux->arena) {
verbose(env, "Only one arena per program\n");
return -EBUSY;
}
if (!env->allow_ptr_leaks || !env->bpf_capable) {
verbose(env, "CAP_BPF and CAP_PERFMON are required to use arena\n");
return -EPERM;
}
if (!env->prog->jit_requested) {
verbose(env, "JIT is required to use arena\n");
return -EOPNOTSUPP;
}
if (!bpf_jit_supports_arena()) {
verbose(env, "JIT doesn't support arena\n");
return -EOPNOTSUPP;
}
env->prog->aux->arena = (void *)map;
if (!bpf_arena_get_user_vm_start(env->prog->aux->arena)) {
verbose(env, "arena's user address must be set via map_extra or mmap()\n");
return -EINVAL;
}
}
return 0;
}
static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
{
return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
}
/* Add map behind fd to used maps list, if it's not already there, and return
* its index. Also set *reused to true if this map was already in the list of
* used maps.
* its index.
* Returns <0 on error, or >= 0 index, on success.
*/
static int add_used_map_from_fd(struct bpf_verifier_env *env, int fd, bool *reused)
static int add_used_map_from_fd(struct bpf_verifier_env *env, int fd)
{
CLASS(fd, f)(fd);
struct bpf_map *map;
int i;
int i, err;
map = __bpf_map_get(f);
if (IS_ERR(map)) {
@@ -19473,12 +19502,9 @@ static int add_used_map_from_fd(struct bpf_verifier_env *env, int fd, bool *reus
}
/* check whether we recorded this map already */
for (i = 0; i < env->used_map_cnt; i++) {
if (env->used_maps[i] == map) {
*reused = true;
for (i = 0; i < env->used_map_cnt; i++)
if (env->used_maps[i] == map)
return i;
}
}
if (env->used_map_cnt >= MAX_USED_MAPS) {
verbose(env, "The total number of maps per program has reached the limit of %u\n",
@@ -19486,6 +19512,10 @@ static int add_used_map_from_fd(struct bpf_verifier_env *env, int fd, bool *reus
return -E2BIG;
}
err = check_map_prog_compatibility(env, map, env->prog);
if (err)
return err;
if (env->prog->sleepable)
atomic64_inc(&map->sleepable_refcnt);
@@ -19496,7 +19526,6 @@ static int add_used_map_from_fd(struct bpf_verifier_env *env, int fd, bool *reus
*/
bpf_map_inc(map);
*reused = false;
env->used_maps[env->used_map_cnt++] = map;
return env->used_map_cnt - 1;
@@ -19533,7 +19562,6 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
int map_idx;
u64 addr;
u32 fd;
bool reused;
if (i == insn_cnt - 1 || insn[1].code != 0 ||
insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
@@ -19594,7 +19622,7 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
break;
}
map_idx = add_used_map_from_fd(env, fd, &reused);
map_idx = add_used_map_from_fd(env, fd);
if (map_idx < 0)
return map_idx;
map = env->used_maps[map_idx];
@@ -19602,10 +19630,6 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
aux = &env->insn_aux_data[i];
aux->map_index = map_idx;
err = check_map_prog_compatibility(env, map, env->prog);
if (err)
return err;
if (insn[0].src_reg == BPF_PSEUDO_MAP_FD ||
insn[0].src_reg == BPF_PSEUDO_MAP_IDX) {
addr = (unsigned long)map;
@@ -19636,39 +19660,6 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
insn[0].imm = (u32)addr;
insn[1].imm = addr >> 32;
/* proceed with extra checks only if its newly added used map */
if (reused)
goto next_insn;
if (bpf_map_is_cgroup_storage(map) &&
bpf_cgroup_storage_assign(env->prog->aux, map)) {
verbose(env, "only one cgroup storage of each type is allowed\n");
return -EBUSY;
}
if (map->map_type == BPF_MAP_TYPE_ARENA) {
if (env->prog->aux->arena) {
verbose(env, "Only one arena per program\n");
return -EBUSY;
}
if (!env->allow_ptr_leaks || !env->bpf_capable) {
verbose(env, "CAP_BPF and CAP_PERFMON are required to use arena\n");
return -EPERM;
}
if (!env->prog->jit_requested) {
verbose(env, "JIT is required to use arena\n");
return -EOPNOTSUPP;
}
if (!bpf_jit_supports_arena()) {
verbose(env, "JIT doesn't support arena\n");
return -EOPNOTSUPP;
}
env->prog->aux->arena = (void *)map;
if (!bpf_arena_get_user_vm_start(env->prog->aux->arena)) {
verbose(env, "arena's user address must be set via map_extra or mmap()\n");
return -EINVAL;
}
}
next_insn:
insn++;
i++;