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Diffstat (limited to 'kernel/bpf/verifier.c')
-rw-r--r--kernel/bpf/verifier.c81
1 files changed, 56 insertions, 25 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bfb45381fb3f..a39eedecc93a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -570,6 +570,8 @@ static const char *reg_type_str(struct bpf_verifier_env *env,
if (type & MEM_RDONLY)
strncpy(prefix, "rdonly_", 16);
+ if (type & MEM_ALLOC)
+ strncpy(prefix, "alloc_", 16);
snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s",
prefix, str[base_type(type)], postfix);
@@ -616,7 +618,7 @@ static void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno)
static void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi)
{
- env->scratched_stack_slots |= 1UL << spi;
+ env->scratched_stack_slots |= 1ULL << spi;
}
static bool reg_scratched(const struct bpf_verifier_env *env, u32 regno)
@@ -637,14 +639,14 @@ static bool verifier_state_scratched(const struct bpf_verifier_env *env)
static void mark_verifier_state_clean(struct bpf_verifier_env *env)
{
env->scratched_regs = 0U;
- env->scratched_stack_slots = 0UL;
+ env->scratched_stack_slots = 0ULL;
}
/* Used for printing the entire verifier state. */
static void mark_verifier_state_scratched(struct bpf_verifier_env *env)
{
env->scratched_regs = ~0U;
- env->scratched_stack_slots = ~0UL;
+ env->scratched_stack_slots = ~0ULL;
}
/* The reg state of a pointer or a bounded scalar was saved when
@@ -3969,16 +3971,17 @@ static int get_callee_stack_depth(struct bpf_verifier_env *env,
}
#endif
-int check_ctx_reg(struct bpf_verifier_env *env,
- const struct bpf_reg_state *reg, int regno)
+static int __check_ptr_off_reg(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno,
+ bool fixed_off_ok)
{
- /* Access to ctx or passing it to a helper is only allowed in
- * its original, unmodified form.
+ /* Access to this pointer-typed register or passing it to a helper
+ * is only allowed in its original, unmodified form.
*/
- if (reg->off) {
- verbose(env, "dereference of modified ctx ptr R%d off=%d disallowed\n",
- regno, reg->off);
+ if (!fixed_off_ok && reg->off) {
+ verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
+ reg_type_str(env, reg->type), regno, reg->off);
return -EACCES;
}
@@ -3986,13 +3989,20 @@ int check_ctx_reg(struct bpf_verifier_env *env,
char tn_buf[48];
tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
- verbose(env, "variable ctx access var_off=%s disallowed\n", tn_buf);
+ verbose(env, "variable %s access var_off=%s disallowed\n",
+ reg_type_str(env, reg->type), tn_buf);
return -EACCES;
}
return 0;
}
+int check_ptr_off_reg(struct bpf_verifier_env *env,
+ const struct bpf_reg_state *reg, int regno)
+{
+ return __check_ptr_off_reg(env, reg, regno, false);
+}
+
static int __check_buffer_access(struct bpf_verifier_env *env,
const char *buf_info,
const struct bpf_reg_state *reg,
@@ -4437,7 +4447,7 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
return -EACCES;
}
- err = check_ctx_reg(env, reg, regno);
+ err = check_ptr_off_reg(env, reg, regno);
if (err < 0)
return err;
@@ -5127,6 +5137,7 @@ static const struct bpf_reg_types mem_types = {
PTR_TO_MAP_KEY,
PTR_TO_MAP_VALUE,
PTR_TO_MEM,
+ PTR_TO_MEM | MEM_ALLOC,
PTR_TO_BUF,
},
};
@@ -5144,7 +5155,7 @@ static const struct bpf_reg_types int_ptr_types = {
static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
-static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM } };
+static const struct bpf_reg_types alloc_mem_types = { .types = { PTR_TO_MEM | MEM_ALLOC } };
static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
@@ -5244,12 +5255,6 @@ found:
kernel_type_name(btf_vmlinux, *arg_btf_id));
return -EACCES;
}
-
- if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
- verbose(env, "R%d is a pointer to in-kernel struct with non-zero offset\n",
- regno);
- return -EACCES;
- }
}
return 0;
@@ -5304,10 +5309,33 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
if (err)
return err;
- if (type == PTR_TO_CTX) {
- err = check_ctx_reg(env, reg, regno);
+ switch ((u32)type) {
+ case SCALAR_VALUE:
+ /* Pointer types where reg offset is explicitly allowed: */
+ case PTR_TO_PACKET:
+ case PTR_TO_PACKET_META:
+ case PTR_TO_MAP_KEY:
+ case PTR_TO_MAP_VALUE:
+ case PTR_TO_MEM:
+ case PTR_TO_MEM | MEM_RDONLY:
+ case PTR_TO_MEM | MEM_ALLOC:
+ case PTR_TO_BUF:
+ case PTR_TO_BUF | MEM_RDONLY:
+ case PTR_TO_STACK:
+ /* Some of the argument types nevertheless require a
+ * zero register offset.
+ */
+ if (arg_type == ARG_PTR_TO_ALLOC_MEM)
+ goto force_off_check;
+ break;
+ /* All the rest must be rejected: */
+ default:
+force_off_check:
+ err = __check_ptr_off_reg(env, reg, regno,
+ type == PTR_TO_BTF_ID);
if (err < 0)
return err;
+ break;
}
skip_type_check:
@@ -9507,9 +9535,13 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
return 0;
}
- if (insn->src_reg == BPF_PSEUDO_BTF_ID) {
- mark_reg_known_zero(env, regs, insn->dst_reg);
+ /* All special src_reg cases are listed below. From this point onwards
+ * we either succeed and assign a corresponding dst_reg->type after
+ * zeroing the offset, or fail and reject the program.
+ */
+ mark_reg_known_zero(env, regs, insn->dst_reg);
+ if (insn->src_reg == BPF_PSEUDO_BTF_ID) {
dst_reg->type = aux->btf_var.reg_type;
switch (base_type(dst_reg->type)) {
case PTR_TO_MEM:
@@ -9547,7 +9579,6 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
}
map = env->used_maps[aux->map_index];
- mark_reg_known_zero(env, regs, insn->dst_reg);
dst_reg->map_ptr = map;
if (insn->src_reg == BPF_PSEUDO_MAP_VALUE ||
@@ -9651,7 +9682,7 @@ static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
return err;
}
- err = check_ctx_reg(env, &regs[ctx_reg], ctx_reg);
+ err = check_ptr_off_reg(env, &regs[ctx_reg], ctx_reg);
if (err < 0)
return err;
generated by cgit (git 2.34.1) at 2025-02-24 20:26:08 +0000