[PATCH bpf] bpf: fix a verifier verbose message

[PATCH bpf] bpf: fix a verifier verbose message

[Anton Protopopov]

Long ago a map file descriptor in a pseudo ldimm64 instruction could
only be present as an immediate value insn[0].imm, and thus this value
was used in a verbose verifier message printed when the file descriptor
wasn't valid. Since addition of BPF_PSEUDO_MAP_IDX_VALUE/BPF_PSEUDO_MAP_IDX
the insn[0].imm field can also contain an index pointing to the file
descriptor in the attr.fd_array array.  However, if the file descriptor
is invalid, the verifier still prints the verbose message containing
value of insn[0].imm. Patch the verifier message to always print the
actual file descriptor value.

Fixes: 387544bfa291 ("bpf: Introduce fd_idx")
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
---
 kernel/bpf/verifier.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 12fcf1901dc2..7e694888d82a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -18293,8 +18293,7 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
 			f = fdget(fd);
 			map = __bpf_map_get(f);
 			if (IS_ERR(map)) {
-				verbose(env, "fd %d is not pointing to valid bpf_map\n",
-					insn[0].imm);
+				verbose(env, "fd %d is not pointing to valid bpf_map\n", fd);
 				return PTR_ERR(map);
 			}
 
-- 
2.34.1

Re: [PATCH bpf] bpf: fix a verifier verbose message

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Fri, 12 Apr 2024 16:11:00 +0200 you wrote:
> Long ago a map file descriptor in a pseudo ldimm64 instruction could
> only be present as an immediate value insn[0].imm, and thus this value
> was used in a verbose verifier message printed when the file descriptor
> wasn't valid. Since addition of BPF_PSEUDO_MAP_IDX_VALUE/BPF_PSEUDO_MAP_IDX
> the insn[0].imm field can also contain an index pointing to the file
> descriptor in the attr.fd_array array.  However, if the file descriptor
> is invalid, the verifier still prints the verbose message containing
> value of insn[0].imm. Patch the verifier message to always print the
> actual file descriptor value.
> 
> [...]

Here is the summary with links:
  - [bpf] bpf: fix a verifier verbose message
    https://git.kernel.org/bpf/bpf/c/37eacb9f6e89

You are awesome, thank you!
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