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-rw-r--r--kernel/bpf/verifier.c102
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c56
2 files changed, 63 insertions, 95 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 */
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 961c1426fbf2..b51017404c62 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -422,9 +422,7 @@ static struct bpf_test tests[] = {
BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
- .errstr_unpriv = "R1 subtraction from stack pointer",
- .result_unpriv = REJECT,
- .errstr = "R1 invalid mem access",
+ .errstr = "R1 subtraction from stack pointer",
.result = REJECT,
},
{
@@ -1859,9 +1857,8 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
- .result = ACCEPT,
- .result_unpriv = REJECT,
- .errstr_unpriv = "R1 pointer += pointer",
+ .result = REJECT,
+ .errstr = "R1 pointer += pointer",
},
{
"unpriv: neg pointer",
@@ -2589,7 +2586,8 @@ static struct bpf_test tests[] = {
BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
offsetof(struct __sk_buff, data)),
BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_4),
- BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+ offsetof(struct __sk_buff, len)),
BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 49),
BPF_ALU64_IMM(BPF_RSH, BPF_REG_2, 49),
BPF_ALU64_REG(BPF_ADD, BPF_REG_3, BPF_REG_2),
@@ -2896,7 +2894,7 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
- .errstr = "invalid access to packet",
+ .errstr = "R3 pointer arithmetic on PTR_TO_PACKET_END",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
@@ -3882,9 +3880,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3, 11 },
- .errstr_unpriv = "R0 pointer += pointer",
- .errstr = "R0 invalid mem access 'inv'",
- .result_unpriv = REJECT,
+ .errstr = "R0 pointer += pointer",
.result = REJECT,
.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
},
@@ -3925,7 +3921,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 4 },
- .errstr = "R4 invalid mem access",
+ .errstr = "R4 pointer arithmetic on PTR_TO_MAP_VALUE_OR_NULL",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS
},
@@ -3946,7 +3942,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 4 },
- .errstr = "R4 invalid mem access",
+ .errstr = "R4 pointer arithmetic on PTR_TO_MAP_VALUE_OR_NULL",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS
},
@@ -3967,7 +3963,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map1 = { 4 },
- .errstr = "R4 invalid mem access",
+ .errstr = "R4 pointer arithmetic on PTR_TO_MAP_VALUE_OR_NULL",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_SCHED_CLS
},
@@ -5192,10 +5188,8 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
- .errstr_unpriv = "R0 bitwise operator &= on pointer",
- .errstr = "invalid mem access 'inv'",
+ .errstr = "R0 bitwise operator &= on pointer",
.result = REJECT,
- .result_unpriv = REJECT,
},
{
"map element value illegal alu op, 2",
@@ -5211,10 +5205,8 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
- .errstr_unpriv = "R0 32-bit pointer arithmetic prohibited",
- .errstr = "invalid mem access 'inv'",
+ .errstr = "R0 32-bit pointer arithmetic prohibited",
.result = REJECT,
- .result_unpriv = REJECT,
},
{
"map element value illegal alu op, 3",
@@ -5230,10 +5222,8 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map2 = { 3 },
- .errstr_unpriv = "R0 pointer arithmetic with /= operator",
- .errstr = "invalid mem access 'inv'",
+ .errstr = "R0 pointer arithmetic with /= operator",
.result = REJECT,
- .result_unpriv = REJECT,
},
{
"map element value illegal alu op, 4",
@@ -6016,8 +6006,7 @@ static struct bpf_test tests[] = {
BPF_EXIT_INSN(),
},
.fixup_map_in_map = { 3 },
- .errstr = "R1 type=inv expected=map_ptr",
- .errstr_unpriv = "R1 pointer arithmetic on CONST_PTR_TO_MAP prohibited",
+ .errstr = "R1 pointer arithmetic on CONST_PTR_TO_MAP prohibited",
.result = REJECT,
},
{
@@ -7645,6 +7634,19 @@ static struct bpf_test tests[] = {
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
},
{
+ "pkt_end - pkt_start is allowed",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct __sk_buff, data_end)),
+ BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
+ offsetof(struct __sk_buff, data)),
+ BPF_ALU64_REG(BPF_SUB, BPF_REG_0, BPF_REG_2),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ },
+ {
"XDP pkt read, pkt_end mangling, bad access 1",
.insns = {
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
@@ -7659,7 +7661,7 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
- .errstr = "R1 offset is outside of the packet",
+ .errstr = "R3 pointer arithmetic on PTR_TO_PACKET_END",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
},
@@ -7678,7 +7680,7 @@ static struct bpf_test tests[] = {
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
- .errstr = "R1 offset is outside of the packet",
+ .errstr = "R3 pointer arithmetic on PTR_TO_PACKET_END",
.result = REJECT,
.prog_type = BPF_PROG_TYPE_XDP,
},
generated by cgit (git 2.34.1) at 2024-06-10 15:00:07 +0000