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-rw-r--r--include/linux/bpf_verifier.h5
-rw-r--r--kernel/bpf/verifier.c27
2 files changed, 20 insertions, 12 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 6023a1367853..06841517ab1e 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -302,10 +302,11 @@ struct bpf_verifier_state_list {
};
/* Possible states for alu_state member. */
-#define BPF_ALU_SANITIZE_SRC 1U
-#define BPF_ALU_SANITIZE_DST 2U
+#define BPF_ALU_SANITIZE_SRC (1U << 0)
+#define BPF_ALU_SANITIZE_DST (1U << 1)
#define BPF_ALU_NEG_VALUE (1U << 2)
#define BPF_ALU_NON_POINTER (1U << 3)
+#define BPF_ALU_IMMEDIATE (1U << 4)
#define BPF_ALU_SANITIZE (BPF_ALU_SANITIZE_SRC | \
BPF_ALU_SANITIZE_DST)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index db347fb125e3..757476c91c98 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6496,6 +6496,7 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
{
struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : tmp_aux;
struct bpf_verifier_state *vstate = env->cur_state;
+ bool off_is_imm = tnum_is_const(off_reg->var_off);
bool off_is_neg = off_reg->smin_value < 0;
bool ptr_is_dst_reg = ptr_reg == dst_reg;
u8 opcode = BPF_OP(insn->code);
@@ -6526,6 +6527,7 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
alu_limit = abs(tmp_aux->alu_limit - alu_limit);
} else {
alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
+ alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
alu_state |= ptr_is_dst_reg ?
BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
}
@@ -12371,7 +12373,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
struct bpf_insn *patch = &insn_buf[0];
- bool issrc, isneg;
+ bool issrc, isneg, isimm;
u32 off_reg;
aux = &env->insn_aux_data[i + delta];
@@ -12382,16 +12384,21 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
BPF_ALU_SANITIZE_SRC;
+ isimm = aux->alu_state & BPF_ALU_IMMEDIATE;
off_reg = issrc ? insn->src_reg : insn->dst_reg;
- if (isneg)
- *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
- *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
- *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
- *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
- *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
- *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
- *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
+ if (isimm) {
+ *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+ } else {
+ if (isneg)
+ *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+ *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+ *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
+ *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
+ *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
+ *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
+ *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
+ }
if (!issrc)
*patch++ = BPF_MOV64_REG(insn->dst_reg, insn->src_reg);
insn->src_reg = BPF_REG_AX;
@@ -12399,7 +12406,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
insn->code = insn->code == code_add ?
code_sub : code_add;
*patch++ = *insn;
- if (issrc && isneg)
+ if (issrc && isneg && !isimm)
*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
cnt = patch - insn_buf;