2020-11-11 05:05:43

by Kaixu Xia

Subject: [PATCH v3] bpf: Fix unsigned 'datasec_id' compared with zero in check_pseudo_btf_id

From: Kaixu Xia <[email protected]>

The unsigned variable datasec_id is assigned a return value from the call
to check_pseudo_btf_id(), which may return negative error code.

Fixes coccicheck warning:

./kernel/bpf/verifier.c:9616:5-15: WARNING: Unsigned expression compared with zero: datasec_id > 0

Reported-by: Tosk Robot <[email protected]>
Signed-off-by: Kaixu Xia <[email protected]>
---
v3:
-put the changes on the proper place.

v2:
-split out datasec_id definition into a separate line.

kernel/bpf/verifier.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 6200519582a6..6204ec705d80 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9572,12 +9572,13 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
struct bpf_insn *insn,
struct bpf_insn_aux_data *aux)
{
- u32 datasec_id, type, id = insn->imm;
const struct btf_var_secinfo *vsi;
const struct btf_type *datasec;
const struct btf_type *t;
const char *sym_name;
bool percpu = false;
+ u32 type, id = insn->imm;
+ s32 datasec_id;
u64 addr;
int i;

--
2.20.0

2020-11-11 05:15:26

by Andrii Nakryiko

Subject: Re: [PATCH v3] bpf: Fix unsigned 'datasec_id' compared with zero in check_pseudo_btf_id

On Tue, Nov 10, 2020 at 9:03 PM <[email protected]> wrote:
>
> From: Kaixu Xia <[email protected]>
>
> The unsigned variable datasec_id is assigned a return value from the call
> to check_pseudo_btf_id(), which may return negative error code.
>
> Fixes coccicheck warning:
>
> ./kernel/bpf/verifier.c:9616:5-15: WARNING: Unsigned expression compared with zero: datasec_id > 0
>
> Reported-by: Tosk Robot <[email protected]>
> Signed-off-by: Kaixu Xia <[email protected]>
> ---

Looks good.

Acked-by: Andrii Nakryiko <[email protected]>

[...]

2020-11-11 09:37:04

by John Fastabend

Subject: Re: [PATCH v3] bpf: Fix unsigned 'datasec_id' compared with zero in check_pseudo_btf_id

Andrii Nakryiko wrote:
> On Tue, Nov 10, 2020 at 9:03 PM <[email protected]> wrote:
> >
> > From: Kaixu Xia <[email protected]>
> >
> > The unsigned variable datasec_id is assigned a return value from the call
> > to check_pseudo_btf_id(), which may return negative error code.
> >
> > Fixes coccicheck warning:
> >
> > ./kernel/bpf/verifier.c:9616:5-15: WARNING: Unsigned expression compared with zero: datasec_id > 0
> >
> > Reported-by: Tosk Robot <[email protected]>
> > Signed-off-by: Kaixu Xia <[email protected]>
> > ---
>
> Looks good.
>
> Acked-by: Andrii Nakryiko <[email protected]>
>
> [...]

Acked-by: John Fastabend <[email protected]>

2020-11-11 10:10:14

by Daniel Borkmann

Subject: Re: [PATCH v3] bpf: Fix unsigned 'datasec_id' compared with zero in check_pseudo_btf_id

On 11/11/20 6:03 AM, [email protected] wrote:
> From: Kaixu Xia <[email protected]>
>
> The unsigned variable datasec_id is assigned a return value from the call
> to check_pseudo_btf_id(), which may return negative error code.
>
> Fixes coccicheck warning:
>
> ./kernel/bpf/verifier.c:9616:5-15: WARNING: Unsigned expression compared with zero: datasec_id > 0
>
> Reported-by: Tosk Robot <[email protected]>
> Signed-off-by: Kaixu Xia <[email protected]>

Looks good, applied & also added Fixes tags, thanks!