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-rw-r--r--kernel/bpf/verifier.c244
1 files changed, 129 insertions, 115 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index dd86282ccaa4..bb99bada7e2e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2750,10 +2750,16 @@ static struct btf *__find_kfunc_desc_btf(struct bpf_verifier_env *env,
b->module = mod;
b->offset = offset;
+ /* sort() reorders entries by value, so b may no longer point
+ * to the right entry after this
+ */
sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
kfunc_btf_cmp_by_off, NULL);
+ } else {
+ btf = b->btf;
}
- return b->btf;
+
+ return btf;
}
void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab)
@@ -6333,10 +6339,10 @@ static void coerce_reg_to_size_sx(struct bpf_reg_state *reg, int size)
/* both of s64_max/s64_min positive or negative */
if ((s64_max >= 0) == (s64_min >= 0)) {
- reg->smin_value = reg->s32_min_value = s64_min;
- reg->smax_value = reg->s32_max_value = s64_max;
- reg->umin_value = reg->u32_min_value = s64_min;
- reg->umax_value = reg->u32_max_value = s64_max;
+ reg->s32_min_value = reg->smin_value = s64_min;
+ reg->s32_max_value = reg->smax_value = s64_max;
+ reg->u32_min_value = reg->umin_value = s64_min;
+ reg->u32_max_value = reg->umax_value = s64_max;
reg->var_off = tnum_range(s64_min, s64_max);
return;
}
@@ -6798,20 +6804,10 @@ static int check_stack_slot_within_bounds(struct bpf_verifier_env *env,
struct bpf_func_state *state,
enum bpf_access_type t)
{
- struct bpf_insn_aux_data *aux = &env->insn_aux_data[env->insn_idx];
- int min_valid_off, max_bpf_stack;
-
- /* If accessing instruction is a spill/fill from bpf_fastcall pattern,
- * add room for all caller saved registers below MAX_BPF_STACK.
- * In case if bpf_fastcall rewrite won't happen maximal stack depth
- * would be checked by check_max_stack_depth_subprog().
- */
- max_bpf_stack = MAX_BPF_STACK;
- if (aux->fastcall_pattern)
- max_bpf_stack += CALLER_SAVED_REGS * BPF_REG_SIZE;
+ int min_valid_off;
if (t == BPF_WRITE || env->allow_uninit_stack)
- min_valid_off = -max_bpf_stack;
+ min_valid_off = -MAX_BPF_STACK;
else
min_valid_off = -state->allocated_stack;
@@ -7432,7 +7428,8 @@ mark:
}
static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
- int access_size, bool zero_size_allowed,
+ int access_size, enum bpf_access_type access_type,
+ bool zero_size_allowed,
struct bpf_call_arg_meta *meta)
{
struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
@@ -7444,7 +7441,7 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
return check_packet_access(env, regno, reg->off, access_size,
zero_size_allowed);
case PTR_TO_MAP_KEY:
- if (meta && meta->raw_mode) {
+ if (access_type == BPF_WRITE) {
verbose(env, "R%d cannot write into %s\n", regno,
reg_type_str(env, reg->type));
return -EACCES;
@@ -7452,15 +7449,13 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
return check_mem_region_access(env, regno, reg->off, access_size,
reg->map_ptr->key_size, false);
case PTR_TO_MAP_VALUE:
- if (check_map_access_type(env, regno, reg->off, access_size,
- meta && meta->raw_mode ? BPF_WRITE :
- BPF_READ))
+ if (check_map_access_type(env, regno, reg->off, access_size, access_type))
return -EACCES;
return check_map_access(env, regno, reg->off, access_size,
zero_size_allowed, ACCESS_HELPER);
case PTR_TO_MEM:
if (type_is_rdonly_mem(reg->type)) {
- if (meta && meta->raw_mode) {
+ if (access_type == BPF_WRITE) {
verbose(env, "R%d cannot write into %s\n", regno,
reg_type_str(env, reg->type));
return -EACCES;
@@ -7471,7 +7466,7 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
zero_size_allowed);
case PTR_TO_BUF:
if (type_is_rdonly_mem(reg->type)) {
- if (meta && meta->raw_mode) {
+ if (access_type == BPF_WRITE) {
verbose(env, "R%d cannot write into %s\n", regno,
reg_type_str(env, reg->type));
return -EACCES;
@@ -7499,7 +7494,6 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
* Dynamically check it now.
*/
if (!env->ops->convert_ctx_access) {
- enum bpf_access_type atype = meta && meta->raw_mode ? BPF_WRITE : BPF_READ;
int offset = access_size - 1;
/* Allow zero-byte read from PTR_TO_CTX */
@@ -7507,7 +7501,7 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
return zero_size_allowed ? 0 : -EACCES;
return check_mem_access(env, env->insn_idx, regno, offset, BPF_B,
- atype, -1, false, false);
+ access_type, -1, false, false);
}
fallthrough;
@@ -7532,6 +7526,7 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
*/
static int check_mem_size_reg(struct bpf_verifier_env *env,
struct bpf_reg_state *reg, u32 regno,
+ enum bpf_access_type access_type,
bool zero_size_allowed,
struct bpf_call_arg_meta *meta)
{
@@ -7547,15 +7542,12 @@ static int check_mem_size_reg(struct bpf_verifier_env *env,
*/
meta->msize_max_value = reg->umax_value;
- /* The register is SCALAR_VALUE; the access check
- * happens using its boundaries.
+ /* The register is SCALAR_VALUE; the access check happens using
+ * its boundaries. For unprivileged variable accesses, disable
+ * raw mode so that the program is required to initialize all
+ * the memory that the helper could just partially fill up.
*/
if (!tnum_is_const(reg->var_off))
- /* For unprivileged variable accesses, disable raw
- * mode so that the program is required to
- * initialize all the memory that the helper could
- * just partially fill up.
- */
meta = NULL;
if (reg->smin_value < 0) {
@@ -7575,9 +7567,8 @@ static int check_mem_size_reg(struct bpf_verifier_env *env,
regno);
return -EACCES;
}
- err = check_helper_mem_access(env, regno - 1,
- reg->umax_value,
- zero_size_allowed, meta);
+ err = check_helper_mem_access(env, regno - 1, reg->umax_value,
+ access_type, zero_size_allowed, meta);
if (!err)
err = mark_chain_precision(env, regno);
return err;
@@ -7588,13 +7579,11 @@ static int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg
{
bool may_be_null = type_may_be_null(reg->type);
struct bpf_reg_state saved_reg;
- struct bpf_call_arg_meta meta;
int err;
if (register_is_null(reg))
return 0;
- memset(&meta, 0, sizeof(meta));
/* 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.
@@ -7604,10 +7593,8 @@ static int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg
mark_ptr_not_null_reg(reg);
}
- err = check_helper_mem_access(env, regno, mem_size, true, &meta);
- /* Check access for BPF_WRITE */
- meta.raw_mode = true;
- err = err ?: check_helper_mem_access(env, regno, mem_size, true, &meta);
+ err = check_helper_mem_access(env, regno, mem_size, BPF_READ, true, NULL);
+ err = err ?: check_helper_mem_access(env, regno, mem_size, BPF_WRITE, true, NULL);
if (may_be_null)
*reg = saved_reg;
@@ -7633,13 +7620,12 @@ static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg
mark_ptr_not_null_reg(mem_reg);
}
- err = check_mem_size_reg(env, reg, regno, true, &meta);
- /* Check access for BPF_WRITE */
- meta.raw_mode = true;
- err = err ?: check_mem_size_reg(env, reg, regno, true, &meta);
+ err = check_mem_size_reg(env, reg, regno, BPF_READ, true, &meta);
+ err = err ?: check_mem_size_reg(env, reg, regno, BPF_WRITE, true, &meta);
if (may_be_null)
*mem_reg = saved_reg;
+
return err;
}
@@ -8942,9 +8928,8 @@ skip_type_check:
verbose(env, "invalid map_ptr to access map->key\n");
return -EACCES;
}
- err = check_helper_mem_access(env, regno,
- meta->map_ptr->key_size, false,
- NULL);
+ err = check_helper_mem_access(env, regno, meta->map_ptr->key_size,
+ BPF_READ, false, NULL);
break;
case ARG_PTR_TO_MAP_VALUE:
if (type_may_be_null(arg_type) && register_is_null(reg))
@@ -8959,9 +8944,9 @@ skip_type_check:
return -EACCES;
}
meta->raw_mode = arg_type & MEM_UNINIT;
- err = check_helper_mem_access(env, regno,
- meta->map_ptr->value_size, false,
- meta);
+ err = check_helper_mem_access(env, regno, meta->map_ptr->value_size,
+ arg_type & MEM_WRITE ? BPF_WRITE : BPF_READ,
+ false, meta);
break;
case ARG_PTR_TO_PERCPU_BTF_ID:
if (!reg->btf_id) {
@@ -9003,7 +8988,9 @@ skip_type_check:
*/
meta->raw_mode = arg_type & MEM_UNINIT;
if (arg_type & MEM_FIXED_SIZE) {
- err = check_helper_mem_access(env, regno, fn->arg_size[arg], false, meta);
+ err = check_helper_mem_access(env, regno, fn->arg_size[arg],
+ arg_type & MEM_WRITE ? BPF_WRITE : BPF_READ,
+ false, meta);
if (err)
return err;
if (arg_type & MEM_ALIGNED)
@@ -9011,10 +8998,16 @@ skip_type_check:
}
break;
case ARG_CONST_SIZE:
- err = check_mem_size_reg(env, reg, regno, false, meta);
+ err = check_mem_size_reg(env, reg, regno,
+ fn->arg_type[arg - 1] & MEM_WRITE ?
+ BPF_WRITE : BPF_READ,
+ false, meta);
break;
case ARG_CONST_SIZE_OR_ZERO:
- err = check_mem_size_reg(env, reg, regno, true, meta);
+ err = check_mem_size_reg(env, reg, regno,
+ fn->arg_type[arg - 1] & MEM_WRITE ?
+ BPF_WRITE : BPF_READ,
+ true, meta);
break;
case ARG_PTR_TO_DYNPTR:
err = process_dynptr_func(env, regno, insn_idx, arg_type, 0);
@@ -14264,12 +14257,13 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
* r1 += 0x1
* if r2 < 1000 goto ...
* use r1 in memory access
- * So remember constant delta between r2 and r1 and update r1 after
- * 'if' condition.
+ * So for 64-bit alu remember constant delta between r2 and r1 and
+ * update r1 after 'if' condition.
*/
- if (env->bpf_capable && BPF_OP(insn->code) == BPF_ADD &&
- dst_reg->id && is_reg_const(src_reg, alu32)) {
- u64 val = reg_const_value(src_reg, alu32);
+ if (env->bpf_capable &&
+ BPF_OP(insn->code) == BPF_ADD && !alu32 &&
+ dst_reg->id && is_reg_const(src_reg, false)) {
+ u64 val = reg_const_value(src_reg, false);
if ((dst_reg->id & BPF_ADD_CONST) ||
/* prevent overflow in sync_linked_regs() later */
@@ -15326,8 +15320,12 @@ static void sync_linked_regs(struct bpf_verifier_state *vstate, struct bpf_reg_s
continue;
if ((!(reg->id & BPF_ADD_CONST) && !(known_reg->id & BPF_ADD_CONST)) ||
reg->off == known_reg->off) {
+ s32 saved_subreg_def = reg->subreg_def;
+
copy_register_state(reg, known_reg);
+ reg->subreg_def = saved_subreg_def;
} else {
+ s32 saved_subreg_def = reg->subreg_def;
s32 saved_off = reg->off;
fake_reg.type = SCALAR_VALUE;
@@ -15340,6 +15338,7 @@ static void sync_linked_regs(struct bpf_verifier_state *vstate, struct bpf_reg_s
* otherwise another sync_linked_regs() will be incorrect.
*/
reg->off = saved_off;
+ reg->subreg_def = saved_subreg_def;
scalar32_min_max_add(reg, &fake_reg);
scalar_min_max_add(reg, &fake_reg);
@@ -17877,9 +17876,11 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
struct bpf_verifier_state_list *sl, **pprev;
struct bpf_verifier_state *cur = env->cur_state, *new, *loop_entry;
int i, j, n, err, states_cnt = 0;
- bool force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx);
- bool add_new_state = force_new_state;
- bool force_exact;
+ bool force_new_state, add_new_state, force_exact;
+
+ force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx) ||
+ /* Avoid accumulating infinitely long jmp history */
+ cur->jmp_history_cnt > 40;
/* bpf progs typically have pruning point every 4 instructions
* http://vger.kernel.org/bpfconf2019.html#session-1
@@ -17889,6 +17890,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
* In tests that amounts to up to 50% reduction into total verifier
* memory consumption and 20% verifier time speedup.
*/
+ add_new_state = force_new_state;
if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
env->insn_processed - env->prev_insn_processed >= 8)
add_new_state = true;
@@ -18920,6 +18922,53 @@ static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
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.
+ * 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)
+{
+ CLASS(fd, f)(fd);
+ struct bpf_map *map;
+ int i;
+
+ map = __bpf_map_get(f);
+ if (IS_ERR(map)) {
+ verbose(env, "fd %d is not pointing to valid bpf_map\n", fd);
+ return PTR_ERR(map);
+ }
+
+ /* check whether we recorded this map already */
+ for (i = 0; i < env->used_map_cnt; i++) {
+ if (env->used_maps[i] == map) {
+ *reused = true;
+ 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",
+ MAX_USED_MAPS);
+ return -E2BIG;
+ }
+
+ if (env->prog->sleepable)
+ atomic64_inc(&map->sleepable_refcnt);
+
+ /* hold the map. If the program is rejected by verifier,
+ * the map will be released by release_maps() or it
+ * will be used by the valid program until it's unloaded
+ * and all maps are released in bpf_free_used_maps()
+ */
+ bpf_map_inc(map);
+
+ *reused = false;
+ env->used_maps[env->used_map_cnt++] = map;
+
+ return env->used_map_cnt - 1;
+}
+
/* find and rewrite pseudo imm in ld_imm64 instructions:
*
* 1. if it accesses map FD, replace it with actual map pointer.
@@ -18931,7 +18980,7 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
{
struct bpf_insn *insn = env->prog->insnsi;
int insn_cnt = env->prog->len;
- int i, j, err;
+ int i, err;
err = bpf_prog_calc_tag(env->prog);
if (err)
@@ -18948,9 +18997,10 @@ static int resolve_pseudo_ldimm64(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;
+ 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 ||
@@ -19011,20 +19061,18 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
break;
}
- f = fdget(fd);
- map = __bpf_map_get(f);
- if (IS_ERR(map)) {
- verbose(env, "fd %d is not pointing to valid bpf_map\n", fd);
- return PTR_ERR(map);
- }
+ map_idx = add_used_map_from_fd(env, fd, &reused);
+ if (map_idx < 0)
+ return map_idx;
+ map = env->used_maps[map_idx];
+
+ aux = &env->insn_aux_data[i];
+ aux->map_index = map_idx;
err = check_map_prog_compatibility(env, map, env->prog);
- if (err) {
- fdput(f);
+ if (err)
return err;
- }
- aux = &env->insn_aux_data[i];
if (insn[0].src_reg == BPF_PSEUDO_MAP_FD ||
insn[0].src_reg == BPF_PSEUDO_MAP_IDX) {
addr = (unsigned long)map;
@@ -19033,13 +19081,11 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
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;
}
@@ -19047,7 +19093,6 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
if (err) {
verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
map->value_size, off);
- fdput(f);
return err;
}
@@ -19058,70 +19103,39 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
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++) {
- if (env->used_maps[j] == map) {
- aux->map_index = j;
- fdput(f);
- goto next_insn;
- }
- }
-
- if (env->used_map_cnt >= MAX_USED_MAPS) {
- verbose(env, "The total number of maps per program has reached the limit of %u\n",
- MAX_USED_MAPS);
- fdput(f);
- return -E2BIG;
- }
-
- if (env->prog->sleepable)
- atomic64_inc(&map->sleepable_refcnt);
- /* hold the map. If the program is rejected by verifier,
- * the map will be released by release_maps() or it
- * will be used by the valid program until it's unloaded
- * and all maps are released in bpf_free_used_maps()
- */
- bpf_map_inc(map);
-
- aux->map_index = env->used_map_cnt;
- env->used_maps[env->used_map_cnt++] = map;
+ /* 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");
- fdput(f);
return -EBUSY;
}
if (map->map_type == BPF_MAP_TYPE_ARENA) {
if (env->prog->aux->arena) {
verbose(env, "Only one arena per program\n");
- fdput(f);
return -EBUSY;
}
if (!env->allow_ptr_leaks || !env->bpf_capable) {
verbose(env, "CAP_BPF and CAP_PERFMON are required to use arena\n");
- fdput(f);
return -EPERM;
}
if (!env->prog->jit_requested) {
verbose(env, "JIT is required to use arena\n");
- fdput(f);
return -EOPNOTSUPP;
}
if (!bpf_jit_supports_arena()) {
verbose(env, "JIT doesn't support arena\n");
- fdput(f);
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");
- fdput(f);
return -EINVAL;
}
}
- fdput(f);
next_insn:
insn++;
i++;
@@ -21189,7 +21203,7 @@ patch_map_ops_generic:
delta += cnt - 1;
env->prog = prog = new_prog;
insn = new_prog->insnsi + i + delta;
- continue;
+ goto next_insn;
}
/* Implement bpf_kptr_xchg inline */
@@ -22298,7 +22312,7 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u3
/* 'struct bpf_verifier_env' can be global, but since it's not small,
* allocate/free it every time bpf_check() is called
*/
- env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
+ env = kvzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
if (!env)
return -ENOMEM;
@@ -22534,6 +22548,6 @@ err_unlock:
mutex_unlock(&bpf_verifier_lock);
vfree(env->insn_aux_data);
err_free_env:
- kfree(env);
+ kvfree(env);
return ret;
}
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