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bpf/verifier: replace calls to mark_reg_unknown.

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In order to further simplify the code in adjust_scalar_min_max_vals all
the calls to mark_reg_unknown are replaced by __mark_reg_unknown.

static void mark_reg_unknown(struct bpf_verifier_env *env,
  			     struct bpf_reg_state *regs, u32 regno)
{
	if (WARN_ON(regno >= MAX_BPF_REG)) {
		... mark all regs not init ...
		return;
    }
	__mark_reg_unknown(env, regs + regno);
}

The 'regno >= MAX_BPF_REG' does not apply to
adjust_scalar_min_max_vals(), because it is only called from the
following stack:
  - check_alu_op
    - adjust_reg_min_max_vals
      - adjust_scalar_min_max_vals

The check_alu_op() does check_reg_arg() which verifies that both src and
dst register numbers are within bounds.

Signed-off-by: Cupertino Miranda <cupertino.miranda@oracle.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Cc: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: David Faust <david.faust@oracle.com>
Cc: Jose Marchesi <jose.marchesi@oracle.com>
Cc: Elena Zannoni <elena.zannoni@oracle.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Link: https://lore.kernel.org/r/20240506141849.185293-2-cupertino.miranda@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Cupertino Miranda 2024-05-06 15:18:44 +01:00 committed by Alexei Starovoitov
parent 41b307ad75
commit d786957ebd
1 changed files with 4 additions and 5 deletions
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9
kernel/bpf/verifier.c
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@ -13887,7 +13887,6 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
struct bpf_reg_state *dst_reg,
struct bpf_reg_state src_reg)
{
struct bpf_reg_state *regs = cur_regs(env);
u8 opcode = BPF_OP(insn->code);
bool src_known;
s64 smin_val, smax_val;
@ -13994,7 +13993,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
/* Shifts greater than 31 or 63 are undefined.
* This includes shifts by a negative number.
*/
mark_reg_unknown(env, regs, insn->dst_reg);
__mark_reg_unknown(env, dst_reg);
break;
}
if (alu32)
@ -14007,7 +14006,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
/* Shifts greater than 31 or 63 are undefined.
* This includes shifts by a negative number.
*/
mark_reg_unknown(env, regs, insn->dst_reg);
__mark_reg_unknown(env, dst_reg);
break;
}
if (alu32)
@ -14020,7 +14019,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
/* Shifts greater than 31 or 63 are undefined.
* This includes shifts by a negative number.
*/
mark_reg_unknown(env, regs, insn->dst_reg);
__mark_reg_unknown(env, dst_reg);
break;
}
if (alu32)
@ -14029,7 +14028,7 @@ static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
scalar_min_max_arsh(dst_reg, &src_reg);
break;
default:
mark_reg_unknown(env, regs, insn->dst_reg);
__mark_reg_unknown(env, dst_reg);
break;
}