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-rw-r--r--kernel/bpf/verifier.c256
1 files changed, 142 insertions, 114 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ab2d6a02aee0..93def76cf32b 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -238,7 +238,9 @@ struct bpf_call_arg_meta {
u64 msize_max_value;
int ref_obj_id;
int func_id;
+ struct btf *btf;
u32 btf_id;
+ struct btf *ret_btf;
u32 ret_btf_id;
};
@@ -556,10 +558,9 @@ static struct bpf_func_state *func(struct bpf_verifier_env *env,
return cur->frame[reg->frameno];
}
-const char *kernel_type_name(u32 id)
+static const char *kernel_type_name(const struct btf* btf, u32 id)
{
- return btf_name_by_offset(btf_vmlinux,
- btf_type_by_id(btf_vmlinux, id)->name_off);
+ return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off);
}
static void print_verifier_state(struct bpf_verifier_env *env,
@@ -589,7 +590,7 @@ static void print_verifier_state(struct bpf_verifier_env *env,
if (t == PTR_TO_BTF_ID ||
t == PTR_TO_BTF_ID_OR_NULL ||
t == PTR_TO_PERCPU_BTF_ID)
- verbose(env, "%s", kernel_type_name(reg->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))
verbose(env, ",ref_obj_id=%d", reg->ref_obj_id);
@@ -1383,7 +1384,8 @@ static void mark_reg_not_init(struct bpf_verifier_env *env,
static void mark_btf_ld_reg(struct bpf_verifier_env *env,
struct bpf_reg_state *regs, u32 regno,
- enum bpf_reg_type reg_type, u32 btf_id)
+ enum bpf_reg_type reg_type,
+ struct btf *btf, u32 btf_id)
{
if (reg_type == SCALAR_VALUE) {
mark_reg_unknown(env, regs, regno);
@@ -1391,6 +1393,7 @@ static void mark_btf_ld_reg(struct bpf_verifier_env *env,
}
mark_reg_known_zero(env, regs, regno);
regs[regno].type = PTR_TO_BTF_ID;
+ regs[regno].btf = btf;
regs[regno].btf_id = btf_id;
}
@@ -2764,7 +2767,7 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
/* check access to 'struct bpf_context' fields. Supports fixed offsets only */
static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
enum bpf_access_type t, enum bpf_reg_type *reg_type,
- u32 *btf_id)
+ struct btf **btf, u32 *btf_id)
{
struct bpf_insn_access_aux info = {
.reg_type = *reg_type,
@@ -2782,10 +2785,12 @@ 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 (*reg_type == PTR_TO_BTF_ID || *reg_type == PTR_TO_BTF_ID_OR_NULL) {
+ *btf = info.btf;
*btf_id = info.btf_id;
- else
+ } else {
env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
+ }
/* remember the offset of last byte accessed in ctx */
if (env->prog->aux->max_ctx_offset < off + size)
env->prog->aux->max_ctx_offset = off + size;
@@ -3297,8 +3302,8 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
int value_regno)
{
struct bpf_reg_state *reg = regs + regno;
- const struct btf_type *t = btf_type_by_id(btf_vmlinux, reg->btf_id);
- const char *tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+ const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
+ const char *tname = btf_name_by_offset(reg->btf, t->name_off);
u32 btf_id;
int ret;
@@ -3319,23 +3324,23 @@ static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
}
if (env->ops->btf_struct_access) {
- ret = env->ops->btf_struct_access(&env->log, t, off, size,
- atype, &btf_id);
+ ret = env->ops->btf_struct_access(&env->log, reg->btf, t,
+ off, size, atype, &btf_id);
} else {
if (atype != BPF_READ) {
verbose(env, "only read is supported\n");
return -EACCES;
}
- ret = btf_struct_access(&env->log, t, off, size, atype,
- &btf_id);
+ ret = btf_struct_access(&env->log, reg->btf, t, off, size,
+ atype, &btf_id);
}
if (ret < 0)
return ret;
if (atype == BPF_READ && value_regno >= 0)
- mark_btf_ld_reg(env, regs, value_regno, ret, btf_id);
+ mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id);
return 0;
}
@@ -3385,12 +3390,12 @@ static int check_ptr_to_map_access(struct bpf_verifier_env *env,
return -EACCES;
}
- ret = btf_struct_access(&env->log, t, off, size, atype, &btf_id);
+ ret = btf_struct_access(&env->log, btf_vmlinux, t, off, size, atype, &btf_id);
if (ret < 0)
return ret;
if (value_regno >= 0)
- mark_btf_ld_reg(env, regs, value_regno, ret, btf_id);
+ mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id);
return 0;
}
@@ -3466,6 +3471,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
mark_reg_unknown(env, regs, value_regno);
} else if (reg->type == PTR_TO_CTX) {
enum bpf_reg_type reg_type = SCALAR_VALUE;
+ struct btf *btf = NULL;
u32 btf_id = 0;
if (t == BPF_WRITE && value_regno >= 0 &&
@@ -3478,7 +3484,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
if (err < 0)
return err;
- err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf_id);
+ err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf, &btf_id);
if (err)
verbose_linfo(env, insn_idx, "; ");
if (!err && t == BPF_READ && value_regno >= 0) {
@@ -3500,8 +3506,10 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
*/
regs[value_regno].subreg_def = DEF_NOT_SUBREG;
if (reg_type == PTR_TO_BTF_ID ||
- reg_type == PTR_TO_BTF_ID_OR_NULL)
+ reg_type == PTR_TO_BTF_ID_OR_NULL) {
+ regs[value_regno].btf = btf;
regs[value_regno].btf_id = btf_id;
+ }
}
regs[value_regno].type = reg_type;
}
@@ -4118,11 +4126,11 @@ found:
arg_btf_id = compatible->btf_id;
}
- if (!btf_struct_ids_match(&env->log, reg->off, reg->btf_id,
- *arg_btf_id)) {
+ if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+ btf_vmlinux, *arg_btf_id)) {
verbose(env, "R%d is of type %s but %s is expected\n",
- regno, kernel_type_name(reg->btf_id),
- kernel_type_name(*arg_btf_id));
+ regno, kernel_type_name(reg->btf, reg->btf_id),
+ kernel_type_name(btf_vmlinux, *arg_btf_id));
return -EACCES;
}
@@ -4244,6 +4252,7 @@ skip_type_check:
verbose(env, "Helper has invalid btf_id in R%d\n", regno);
return -EACCES;
}
+ meta->ret_btf = reg->btf;
meta->ret_btf_id = reg->btf_id;
} else if (arg_type == ARG_PTR_TO_SPIN_LOCK) {
if (meta->func_id == BPF_FUNC_spin_lock) {
@@ -5190,16 +5199,16 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
const struct btf_type *t;
mark_reg_known_zero(env, regs, BPF_REG_0);
- t = btf_type_skip_modifiers(btf_vmlinux, meta.ret_btf_id, NULL);
+ t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL);
if (!btf_type_is_struct(t)) {
u32 tsize;
const struct btf_type *ret;
const char *tname;
/* resolve the type size of ksym. */
- ret = btf_resolve_size(btf_vmlinux, t, &tsize);
+ ret = btf_resolve_size(meta.ret_btf, t, &tsize);
if (IS_ERR(ret)) {
- tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+ tname = btf_name_by_offset(meta.ret_btf, t->name_off);
verbose(env, "unable to resolve the size of type '%s': %ld\n",
tname, PTR_ERR(ret));
return -EINVAL;
@@ -5212,6 +5221,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
regs[BPF_REG_0].type =
fn->ret_type == RET_PTR_TO_MEM_OR_BTF_ID ?
PTR_TO_BTF_ID : PTR_TO_BTF_ID_OR_NULL;
+ regs[BPF_REG_0].btf = meta.ret_btf;
regs[BPF_REG_0].btf_id = meta.ret_btf_id;
}
} else if (fn->ret_type == RET_PTR_TO_BTF_ID_OR_NULL ||
@@ -5228,6 +5238,10 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
fn->ret_type, func_id_name(func_id), func_id);
return -EINVAL;
}
+ /* current BPF helper definitions are only coming from
+ * built-in code with type IDs from vmlinux BTF
+ */
+ regs[BPF_REG_0].btf = btf_vmlinux;
regs[BPF_REG_0].btf_id = ret_btf_id;
} else {
verbose(env, "unknown return type %d of func %s#%d\n",
@@ -5627,7 +5641,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
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->raw = 0;
+ memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
}
break;
case BPF_SUB:
@@ -5692,7 +5706,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
dst_reg->id = ++env->id_gen;
/* something was added to pkt_ptr, set range to zero */
if (smin_val < 0)
- dst_reg->raw = 0;
+ memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
}
break;
case BPF_AND:
@@ -7744,6 +7758,7 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
break;
case PTR_TO_BTF_ID:
case PTR_TO_PERCPU_BTF_ID:
+ dst_reg->btf = aux->btf_var.btf;
dst_reg->btf_id = aux->btf_var.btf_id;
break;
default:
@@ -8058,6 +8073,11 @@ static void init_explored_state(struct bpf_verifier_env *env, int idx)
env->insn_aux_data[idx].prune_point = true;
}
+enum {
+ DONE_EXPLORING = 0,
+ KEEP_EXPLORING = 1,
+};
+
/* t, w, e - match pseudo-code above:
* t - index of current instruction
* w - next instruction
@@ -8070,10 +8090,10 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
int *insn_state = env->cfg.insn_state;
if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
- return 0;
+ return DONE_EXPLORING;
if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
- return 0;
+ return DONE_EXPLORING;
if (w < 0 || w >= env->prog->len) {
verbose_linfo(env, t, "%d: ", t);
@@ -8092,10 +8112,10 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
if (env->cfg.cur_stack >= env->prog->len)
return -E2BIG;
insn_stack[env->cfg.cur_stack++] = w;
- return 1;
+ return KEEP_EXPLORING;
} else if ((insn_state[w] & 0xF0) == DISCOVERED) {
if (loop_ok && env->bpf_capable)
- return 0;
+ return DONE_EXPLORING;
verbose_linfo(env, t, "%d: ", t);
verbose_linfo(env, w, "%d: ", w);
verbose(env, "back-edge from insn %d to %d\n", t, w);
@@ -8107,7 +8127,74 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
verbose(env, "insn state internal bug\n");
return -EFAULT;
}
- return 0;
+ return DONE_EXPLORING;
+}
+
+/* Visits the instruction at index t and returns one of the following:
+ * < 0 - an error occurred
+ * DONE_EXPLORING - the instruction was fully explored
+ * KEEP_EXPLORING - there is still work to be done before it is fully explored
+ */
+static int visit_insn(int t, int insn_cnt, struct bpf_verifier_env *env)
+{
+ struct bpf_insn *insns = env->prog->insnsi;
+ int ret;
+
+ /* All non-branch instructions have a single fall-through edge. */
+ if (BPF_CLASS(insns[t].code) != BPF_JMP &&
+ BPF_CLASS(insns[t].code) != BPF_JMP32)
+ return push_insn(t, t + 1, FALLTHROUGH, env, false);
+
+ switch (BPF_OP(insns[t].code)) {
+ case BPF_EXIT:
+ return DONE_EXPLORING;
+
+ case BPF_CALL:
+ ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
+ if (ret)
+ return ret;
+
+ if (t + 1 < insn_cnt)
+ init_explored_state(env, t + 1);
+ if (insns[t].src_reg == BPF_PSEUDO_CALL) {
+ init_explored_state(env, t);
+ ret = push_insn(t, t + insns[t].imm + 1, BRANCH,
+ env, false);
+ }
+ return ret;
+
+ case BPF_JA:
+ if (BPF_SRC(insns[t].code) != BPF_K)
+ return -EINVAL;
+
+ /* unconditional jump with single edge */
+ ret = push_insn(t, t + insns[t].off + 1, FALLTHROUGH, env,
+ true);
+ if (ret)
+ return ret;
+
+ /* unconditional jmp is not a good pruning point,
+ * but it's marked, since backtracking needs
+ * to record jmp history in is_state_visited().
+ */
+ init_explored_state(env, t + insns[t].off + 1);
+ /* tell verifier to check for equivalent states
+ * after every call and jump
+ */
+ if (t + 1 < insn_cnt)
+ init_explored_state(env, t + 1);
+
+ return ret;
+
+ default:
+ /* conditional jump with two edges */
+ init_explored_state(env, t);
+ ret = push_insn(t, t + 1, FALLTHROUGH, env, true);
+ if (ret)
+ return ret;
+
+ return push_insn(t, t + insns[t].off + 1, BRANCH, env, true);
+ }
}
/* non-recursive depth-first-search to detect loops in BPF program
@@ -8115,11 +8202,10 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
*/
static int check_cfg(struct bpf_verifier_env *env)
{
- struct bpf_insn *insns = env->prog->insnsi;
int insn_cnt = env->prog->len;
int *insn_stack, *insn_state;
int ret = 0;
- int i, t;
+ int i;
insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
if (!insn_state)
@@ -8135,92 +8221,32 @@ static int check_cfg(struct bpf_verifier_env *env)
insn_stack[0] = 0; /* 0 is the first instruction */
env->cfg.cur_stack = 1;
-peek_stack:
- if (env->cfg.cur_stack == 0)
- goto check_state;
- t = insn_stack[env->cfg.cur_stack - 1];
-
- if (BPF_CLASS(insns[t].code) == BPF_JMP ||
- BPF_CLASS(insns[t].code) == BPF_JMP32) {
- u8 opcode = BPF_OP(insns[t].code);
-
- if (opcode == BPF_EXIT) {
- goto mark_explored;
- } else if (opcode == BPF_CALL) {
- ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
- if (ret == 1)
- goto peek_stack;
- else if (ret < 0)
- goto err_free;
- if (t + 1 < insn_cnt)
- init_explored_state(env, t + 1);
- if (insns[t].src_reg == BPF_PSEUDO_CALL) {
- init_explored_state(env, t);
- ret = push_insn(t, t + insns[t].imm + 1, BRANCH,
- env, false);
- if (ret == 1)
- goto peek_stack;
- else if (ret < 0)
- goto err_free;
- }
- } else if (opcode == BPF_JA) {
- if (BPF_SRC(insns[t].code) != BPF_K) {
- ret = -EINVAL;
- goto err_free;
- }
- /* unconditional jump with single edge */
- ret = push_insn(t, t + insns[t].off + 1,
- FALLTHROUGH, env, true);
- if (ret == 1)
- goto peek_stack;
- else if (ret < 0)
- goto err_free;
- /* unconditional jmp is not a good pruning point,
- * but it's marked, since backtracking needs
- * to record jmp history in is_state_visited().
- */
- init_explored_state(env, t + insns[t].off + 1);
- /* tell verifier to check for equivalent states
- * after every call and jump
- */
- if (t + 1 < insn_cnt)
- init_explored_state(env, t + 1);
- } else {
- /* conditional jump with two edges */
- init_explored_state(env, t);
- ret = push_insn(t, t + 1, FALLTHROUGH, env, true);
- if (ret == 1)
- goto peek_stack;
- else if (ret < 0)
- goto err_free;
+ while (env->cfg.cur_stack > 0) {
+ int t = insn_stack[env->cfg.cur_stack - 1];
- ret = push_insn(t, t + insns[t].off + 1, BRANCH, env, true);
- if (ret == 1)
- goto peek_stack;
- else if (ret < 0)
- goto err_free;
- }
- } else {
- /* all other non-branch instructions with single
- * fall-through edge
- */
- ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
- if (ret == 1)
- goto peek_stack;
- else if (ret < 0)
+ ret = visit_insn(t, insn_cnt, env);
+ switch (ret) {
+ case DONE_EXPLORING:
+ insn_state[t] = EXPLORED;
+ env->cfg.cur_stack--;
+ break;
+ case KEEP_EXPLORING:
+ break;
+ default:
+ if (ret > 0) {
+ verbose(env, "visit_insn internal bug\n");
+ ret = -EFAULT;
+ }
goto err_free;
+ }
}
-mark_explored:
- insn_state[t] = EXPLORED;
- if (env->cfg.cur_stack-- <= 0) {
+ if (env->cfg.cur_stack < 0) {
verbose(env, "pop stack internal bug\n");
ret = -EFAULT;
goto err_free;
}
- goto peek_stack;
-check_state:
for (i = 0; i < insn_cnt; i++) {
if (insn_state[i] != EXPLORED) {
verbose(env, "unreachable insn %d\n", i);
@@ -9740,6 +9766,7 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
t = btf_type_skip_modifiers(btf_vmlinux, type, NULL);
if (percpu) {
aux->btf_var.reg_type = PTR_TO_PERCPU_BTF_ID;
+ aux->btf_var.btf = btf_vmlinux;
aux->btf_var.btf_id = type;
} else if (!btf_type_is_struct(t)) {
const struct btf_type *ret;
@@ -9758,6 +9785,7 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
aux->btf_var.mem_size = tsize;
} else {
aux->btf_var.reg_type = PTR_TO_BTF_ID;
+ aux->btf_var.btf = btf_vmlinux;
aux->btf_var.btf_id = type;
}
return 0;
@@ -11610,7 +11638,7 @@ int bpf_check_attach_target(struct bpf_verifier_log *log,
bpf_log(log, "Tracing programs must provide btf_id\n");
return -EINVAL;
}
- btf = tgt_prog ? tgt_prog->aux->btf : btf_vmlinux;
+ btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
if (!btf) {
bpf_log(log,
"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
@@ -11886,7 +11914,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env)
return ret;
}
- key = bpf_trampoline_compute_key(tgt_prog, btf_id);
+ key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
tr = bpf_trampoline_get(key, &tgt_info);
if (!tr)
return -ENOMEM;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 00:23:53 +0000