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-rw-r--r--kernel/bpf/verifier.c11
-rw-r--r--tools/testing/selftests/bpf/test_verifier.c18
2 files changed, 23 insertions, 6 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 6f8b6ed690be..c2ff608c1984 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1924,6 +1924,17 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
return 0;
} else if (opcode == BPF_ADD &&
BPF_CLASS(insn->code) == BPF_ALU64 &&
+ dst_reg->type == PTR_TO_STACK &&
+ ((BPF_SRC(insn->code) == BPF_X &&
+ regs[insn->src_reg].type == CONST_IMM) ||
+ BPF_SRC(insn->code) == BPF_K)) {
+ if (BPF_SRC(insn->code) == BPF_X)
+ dst_reg->imm += regs[insn->src_reg].imm;
+ else
+ dst_reg->imm += insn->imm;
+ return 0;
+ } else if (opcode == BPF_ADD &&
+ BPF_CLASS(insn->code) == BPF_ALU64 &&
(dst_reg->type == PTR_TO_PACKET ||
(BPF_SRC(insn->code) == BPF_X &&
regs[insn->src_reg].type == PTR_TO_PACKET))) {
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index d3395c192a24..3773562056da 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -1932,16 +1932,22 @@ static struct bpf_test tests[] = {
.result = ACCEPT,
},
{
- "unpriv: obfuscate stack pointer",
+ "stack pointer arithmetic",
.insns = {
- BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
- BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+ BPF_MOV64_IMM(BPF_REG_1, 4),
+ BPF_JMP_IMM(BPF_JA, 0, 0, 0),
+ BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -10),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -10),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
+ BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_1),
+ BPF_ST_MEM(0, BPF_REG_2, 4, 0),
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 8),
+ BPF_ST_MEM(0, BPF_REG_2, 4, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
- .errstr_unpriv = "R2 pointer arithmetic",
- .result_unpriv = REJECT,
.result = ACCEPT,
},
{