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-rw-r--r--kernel/bpf/verifier.c102
1 files changed, 34 insertions, 68 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 86dfe6b5c243..04b24876cd23 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1890,29 +1890,25 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
if (BPF_CLASS(insn->code) != BPF_ALU64) {
/* 32-bit ALU ops on pointers produce (meaningless) scalars */
- if (!env->allow_ptr_leaks)
- verbose(env,
- "R%d 32-bit pointer arithmetic prohibited\n",
- dst);
+ verbose(env,
+ "R%d 32-bit pointer arithmetic prohibited\n",
+ dst);
return -EACCES;
}
if (ptr_reg->type == PTR_TO_MAP_VALUE_OR_NULL) {
- if (!env->allow_ptr_leaks)
- verbose(env, "R%d pointer arithmetic on PTR_TO_MAP_VALUE_OR_NULL prohibited, null-check it first\n",
- dst);
+ verbose(env, "R%d pointer arithmetic on PTR_TO_MAP_VALUE_OR_NULL prohibited, null-check it first\n",
+ dst);
return -EACCES;
}
if (ptr_reg->type == CONST_PTR_TO_MAP) {
- if (!env->allow_ptr_leaks)
- verbose(env, "R%d pointer arithmetic on CONST_PTR_TO_MAP prohibited\n",
- dst);
+ verbose(env, "R%d pointer arithmetic on CONST_PTR_TO_MAP prohibited\n",
+ dst);
return -EACCES;
}
if (ptr_reg->type == PTR_TO_PACKET_END) {
- if (!env->allow_ptr_leaks)
- verbose(env, "R%d pointer arithmetic on PTR_TO_PACKET_END prohibited\n",
- dst);
+ verbose(env, "R%d pointer arithmetic on PTR_TO_PACKET_END prohibited\n",
+ dst);
return -EACCES;
}
@@ -1979,9 +1975,8 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
case BPF_SUB:
if (dst_reg == off_reg) {
/* scalar -= pointer. Creates an unknown scalar */
- if (!env->allow_ptr_leaks)
- verbose(env, "R%d tried to subtract pointer from scalar\n",
- dst);
+ verbose(env, "R%d tried to subtract pointer from scalar\n",
+ dst);
return -EACCES;
}
/* We don't allow subtraction from FP, because (according to
@@ -1989,9 +1984,8 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
* be able to deal with it.
*/
if (ptr_reg->type == PTR_TO_STACK) {
- if (!env->allow_ptr_leaks)
- verbose(env, "R%d subtraction from stack pointer prohibited\n",
- dst);
+ verbose(env, "R%d subtraction from stack pointer prohibited\n",
+ dst);
return -EACCES;
}
if (known && (ptr_reg->off - smin_val ==
@@ -2040,19 +2034,14 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
case BPF_AND:
case BPF_OR:
case BPF_XOR:
- /* bitwise ops on pointers are troublesome, prohibit for now.
- * (However, in principle we could allow some cases, e.g.
- * ptr &= ~3 which would reduce min_value by 3.)
- */
- if (!env->allow_ptr_leaks)
- verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
- dst, bpf_alu_string[opcode >> 4]);
+ /* bitwise ops on pointers are troublesome, prohibit. */
+ verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
+ dst, bpf_alu_string[opcode >> 4]);
return -EACCES;
default:
/* other operators (e.g. MUL,LSH) produce non-pointer results */
- if (!env->allow_ptr_leaks)
- verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
- dst, bpf_alu_string[opcode >> 4]);
+ verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
+ dst, bpf_alu_string[opcode >> 4]);
return -EACCES;
}
@@ -2308,7 +2297,6 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
struct bpf_reg_state *regs = cur_regs(env), *dst_reg, *src_reg;
struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
u8 opcode = BPF_OP(insn->code);
- int rc;
dst_reg = &regs[insn->dst_reg];
src_reg = NULL;
@@ -2319,43 +2307,29 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
if (src_reg->type != SCALAR_VALUE) {
if (dst_reg->type != SCALAR_VALUE) {
/* Combining two pointers by any ALU op yields
- * an arbitrary scalar.
+ * an arbitrary scalar. Disallow all math except
+ * pointer subtraction
*/
- if (!env->allow_ptr_leaks) {
- verbose(env, "R%d pointer %s pointer prohibited\n",
- insn->dst_reg,
- bpf_alu_string[opcode >> 4]);
- return -EACCES;
+ if (opcode == BPF_SUB){
+ mark_reg_unknown(env, regs, insn->dst_reg);
+ return 0;
}
- mark_reg_unknown(env, regs, insn->dst_reg);
- return 0;
+ verbose(env, "R%d pointer %s pointer prohibited\n",
+ insn->dst_reg,
+ bpf_alu_string[opcode >> 4]);
+ return -EACCES;
} else {
/* scalar += pointer
* This is legal, but we have to reverse our
* src/dest handling in computing the range
*/
- rc = adjust_ptr_min_max_vals(env, insn,
- src_reg, dst_reg);
- if (rc == -EACCES && env->allow_ptr_leaks) {
- /* scalar += unknown scalar */
- __mark_reg_unknown(&off_reg);
- return adjust_scalar_min_max_vals(
- env, insn,
- dst_reg, off_reg);
- }
- return rc;
+ return adjust_ptr_min_max_vals(env, insn,
+ src_reg, dst_reg);
}
} else if (ptr_reg) {
/* pointer += scalar */
- rc = adjust_ptr_min_max_vals(env, insn,
- dst_reg, src_reg);
- if (rc == -EACCES && env->allow_ptr_leaks) {
- /* unknown scalar += scalar */
- __mark_reg_unknown(dst_reg);
- return adjust_scalar_min_max_vals(
- env, insn, dst_reg, *src_reg);
- }
- return rc;
+ return adjust_ptr_min_max_vals(env, insn,
+ dst_reg, src_reg);
}
} else {
/* Pretend the src is a reg with a known value, since we only
@@ -2364,17 +2338,9 @@ static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
off_reg.type = SCALAR_VALUE;
__mark_reg_known(&off_reg, insn->imm);
src_reg = &off_reg;
- if (ptr_reg) { /* pointer += K */
- rc = adjust_ptr_min_max_vals(env, insn,
- ptr_reg, src_reg);
- if (rc == -EACCES && env->allow_ptr_leaks) {
- /* unknown scalar += K */
- __mark_reg_unknown(dst_reg);
- return adjust_scalar_min_max_vals(
- env, insn, dst_reg, off_reg);
- }
- return rc;
- }
+ if (ptr_reg) /* pointer += K */
+ return adjust_ptr_min_max_vals(env, insn,
+ ptr_reg, src_reg);
}
/* Got here implies adding two SCALAR_VALUEs */
generated by cgit v1.2.3 (git 2.39.0) at 2024-07-30 04:41:38 +0300