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bpf: Move sanitize_val_alu out of op switch

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Add a small sanitize_needed() helper function and move sanitize_val_alu()
out of the main opcode switch. In upcoming work, we'll move sanitize_ptr_alu()
as well out of its opcode switch so this helps to streamline both.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Daniel Borkmann 2021-03-24 11:25:39 +01:00
parent 073815b756
commit f528819334
1 changed files with 11 additions and 6 deletions
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17
kernel/bpf/verifier.c
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@ -5945,6 +5945,11 @@ static int sanitize_val_alu(struct bpf_verifier_env *env,
return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
}
static bool sanitize_needed(u8 opcode)
{
return opcode == BPF_ADD || opcode == BPF_SUB;
}
static int sanitize_ptr_alu(struct bpf_verifier_env *env,
struct bpf_insn *insn,
const struct bpf_reg_state *ptr_reg,
@ -6968,6 +6973,12 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
return 0;
}
if (sanitize_needed(opcode)) {
ret = sanitize_val_alu(env, insn);
if (ret < 0)
return sanitize_err(env, insn, ret, NULL, NULL);
}
/* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
* There are two classes of instructions: The first class we track both
* alu32 and alu64 sign/unsigned bounds independently this provides the
@ -6984,17 +6995,11 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
*/
switch (opcode) {
case BPF_ADD:
ret = sanitize_val_alu(env, insn);
if (ret < 0)
return sanitize_err(env, insn, ret, NULL, NULL);
scalar32_min_max_add(dst_reg, &src_reg);
scalar_min_max_add(dst_reg, &src_reg);
dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
break;
case BPF_SUB:
ret = sanitize_val_alu(env, insn);
if (ret < 0)
return sanitize_err(env, insn, ret, NULL, NULL);
scalar32_min_max_sub(dst_reg, &src_reg);
scalar_min_max_sub(dst_reg, &src_reg);
dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off);