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[bpf-next] bpf: Check for helper calls in check_subprogs()

Message ID 20230220163756.753713-1-iii@linux.ibm.com (mailing list archive)
State Accepted
Commit df2ccc180a2e6f6e4343ebee99dcfab4f8af2816
Delegated to: BPF
Headers show
Series [bpf-next] bpf: Check for helper calls in check_subprogs() | expand

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Context Check Description
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 10 this patch: 10
netdev/cc_maintainers warning 6 maintainers not CCed: john.fastabend@gmail.com song@kernel.org martin.lau@linux.dev haoluo@google.com yhs@fb.com kpsingh@kernel.org
netdev/build_clang success Errors and warnings before: 1 this patch: 1
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
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netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 10 lines checked
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Commit Message

Ilya Leoshkevich Feb. 20, 2023, 4:37 p.m. UTC 
The condition src_reg != BPF_PSEUDO_CALL && imm == BPF_FUNC_tail_call
may be satisfied by a kfunc call. This would lead to unnecessarily
setting has_tail_call. Use src_reg == 0 instead.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 kernel/bpf/verifier.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Stanislav Fomichev Feb. 21, 2023, 5:10 p.m. UTC | #1 
On Mon, Feb 20, 2023 at 8:38 AM Ilya Leoshkevich <iii@linux.ibm.com> wrote:
>
> The condition src_reg != BPF_PSEUDO_CALL && imm == BPF_FUNC_tail_call
> may be satisfied by a kfunc call. This would lead to unnecessarily
> setting has_tail_call. Use src_reg == 0 instead.

Acked-by: Stanislav Fomichev <sdf@google.com>

(although not sure on src_reg == 0 vs !src_reg. Alexei seems to be
favoring the latter?)


> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  kernel/bpf/verifier.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index e63af41a7e95..6d4632476c9c 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -2462,8 +2462,8 @@ static int check_subprogs(struct bpf_verifier_env *env)
>                 u8 code = insn[i].code;
>
>                 if (code == (BPF_JMP | BPF_CALL) &&
> -                   insn[i].imm == BPF_FUNC_tail_call &&
> -                   insn[i].src_reg != BPF_PSEUDO_CALL)
> +                   insn[i].src_reg == 0 &&
> +                   insn[i].imm == BPF_FUNC_tail_call)
>                         subprog[cur_subprog].has_tail_call = true;
>                 if (BPF_CLASS(code) == BPF_LD &&
>                     (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
> --
> 2.39.1
>
patchwork-bot+netdevbpf@kernel.org Feb. 22, 2023, 9:20 p.m. UTC | #2 
Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Mon, 20 Feb 2023 17:37:56 +0100 you wrote:
> The condition src_reg != BPF_PSEUDO_CALL && imm == BPF_FUNC_tail_call
> may be satisfied by a kfunc call. This would lead to unnecessarily
> setting has_tail_call. Use src_reg == 0 instead.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  kernel/bpf/verifier.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Here is the summary with links:
  - [bpf-next] bpf: Check for helper calls in check_subprogs()
    https://git.kernel.org/bpf/bpf-next/c/df2ccc180a2e

You are awesome, thank you!
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index e63af41a7e95..6d4632476c9c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2462,8 +2462,8 @@  static int check_subprogs(struct bpf_verifier_env *env)
 		u8 code = insn[i].code;
 
 		if (code == (BPF_JMP | BPF_CALL) &&
-		    insn[i].imm == BPF_FUNC_tail_call &&
-		    insn[i].src_reg != BPF_PSEUDO_CALL)
+		    insn[i].src_reg == 0 &&
+		    insn[i].imm == BPF_FUNC_tail_call)
 			subprog[cur_subprog].has_tail_call = true;
 		if (BPF_CLASS(code) == BPF_LD &&
 		    (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))