* [PATCH V2] net: bpf: switch over to memdup_user()
@ 2021-10-18 11:30 Qing Wang
2021-10-18 16:26 ` John Fastabend
0 siblings, 1 reply; 2+ messages in thread
From: Qing Wang @ 2021-10-18 11:30 UTC (permalink / raw)
To: David S. Miller, Jakub Kicinski, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, netdev, bpf,
linux-kernel
Cc: Qing Wang
This patch fixes the following Coccinelle warning:
net/bpf/test_run.c:361:8-15: WARNING opportunity for memdup_user
net/bpf/test_run.c:1055:8-15: WARNING opportunity for memdup_user
Use memdup_user rather than duplicating its implementation
This is a little bit restricted to reduce false positives
Signed-off-by: Qing Wang <wangqing@vivo.com>
---
net/bpf/test_run.c | 21 ++++++---------------
1 file changed, 6 insertions(+), 15 deletions(-)
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 5296087..fbda8f5
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -358,13 +358,9 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
return -EINVAL;
if (ctx_size_in) {
- info.ctx = kzalloc(ctx_size_in, GFP_USER);
- if (!info.ctx)
- return -ENOMEM;
- if (copy_from_user(info.ctx, ctx_in, ctx_size_in)) {
- err = -EFAULT;
- goto out;
- }
+ info.ctx = memdup_user(ctx_in, ctx_size_in);
+ if (IS_ERR(info.ctx))
+ return PTR_ERR(info.ctx);
} else {
info.ctx = NULL;
}
@@ -392,7 +388,6 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
err = -EFAULT;
-out:
kfree(info.ctx);
return err;
}
@@ -1052,13 +1047,9 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog,
return -EINVAL;
if (ctx_size_in) {
- ctx = kzalloc(ctx_size_in, GFP_USER);
- if (!ctx)
- return -ENOMEM;
- if (copy_from_user(ctx, ctx_in, ctx_size_in)) {
- err = -EFAULT;
- goto out;
- }
+ ctx = memdup_user(ctx_in, ctx_size_in);
+ if (IS_ERR(ctx))
+ return PTR_ERR(ctx);
}
rcu_read_lock_trace();
--
2.7.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* RE: [PATCH V2] net: bpf: switch over to memdup_user()
2021-10-18 11:30 [PATCH V2] net: bpf: switch over to memdup_user() Qing Wang
@ 2021-10-18 16:26 ` John Fastabend
0 siblings, 0 replies; 2+ messages in thread
From: John Fastabend @ 2021-10-18 16:26 UTC (permalink / raw)
To: Qing Wang, David S. Miller, Jakub Kicinski, Alexei Starovoitov,
Daniel Borkmann, Andrii Nakryiko, Martin KaFai Lau, Song Liu,
Yonghong Song, John Fastabend, KP Singh, netdev, bpf,
linux-kernel
Cc: Qing Wang
Qing Wang wrote:
> This patch fixes the following Coccinelle warning:
>
> net/bpf/test_run.c:361:8-15: WARNING opportunity for memdup_user
> net/bpf/test_run.c:1055:8-15: WARNING opportunity for memdup_user
>
> Use memdup_user rather than duplicating its implementation
> This is a little bit restricted to reduce false positives
>
> Signed-off-by: Qing Wang <wangqing@vivo.com>
> ---
> net/bpf/test_run.c | 21 ++++++---------------
> 1 file changed, 6 insertions(+), 15 deletions(-)
LGTM, but subject line should be '[PATCH bpf-next v2]' there is no reason
to push to fixes trees here.
Also might be worth noting that the original kzalloc could have just been
a kalloc because copy_from_user will zero any extra bytes.
Acked-by: John Fastabend <john.fastabend@gmail.com>
>
> diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
> index 5296087..fbda8f5
> --- a/net/bpf/test_run.c
> +++ b/net/bpf/test_run.c
> @@ -358,13 +358,9 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
> return -EINVAL;
>
> if (ctx_size_in) {
> - info.ctx = kzalloc(ctx_size_in, GFP_USER);
> - if (!info.ctx)
> - return -ENOMEM;
> - if (copy_from_user(info.ctx, ctx_in, ctx_size_in)) {
> - err = -EFAULT;
> - goto out;
> - }
> + info.ctx = memdup_user(ctx_in, ctx_size_in);
> + if (IS_ERR(info.ctx))
> + return PTR_ERR(info.ctx);
> } else {
> info.ctx = NULL;
> }
> @@ -392,7 +388,6 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
> copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
> err = -EFAULT;
>
> -out:
> kfree(info.ctx);
> return err;
> }
> @@ -1052,13 +1047,9 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog,
> return -EINVAL;
>
> if (ctx_size_in) {
> - ctx = kzalloc(ctx_size_in, GFP_USER);
> - if (!ctx)
> - return -ENOMEM;
> - if (copy_from_user(ctx, ctx_in, ctx_size_in)) {
> - err = -EFAULT;
> - goto out;
> - }
> + ctx = memdup_user(ctx_in, ctx_size_in);
> + if (IS_ERR(ctx))
> + return PTR_ERR(ctx);
> }
>
> rcu_read_lock_trace();
> --
> 2.7.4
>
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