[PATCH 5.11 122/122] bpf: Move sanitize_val_alu out of op switch

Greg Kroah-Hartman
2021-04-19T13:17:29Z

From: Daniel Borkmann <daniel@iogearbox.net>

commit f528819334881fd622fdadeddb3f7edaed8b7c9b upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/bpf/verifier.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)

--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5473,6 +5473,11 @@ static int sanitize_val_alu(struct bpf_v
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,
@@ -6445,6 +6450,12 @@ static int adjust_scalar_min_max_vals(st
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
@@ -6461,17 +6472,11 @@ static int adjust_scalar_min_max_vals(st
*/
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);