From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: davem@davemloft.net
Cc: kuba@kernel.org, edumazet@google.com, pabeni@redhat.com,
daniel@iogearbox.net, andrii@kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org, kernel-team@fb.com
Subject: [PATCH bpf-next] bpf, net: Introduce skb_pointer_if_linear().
Date: Tue, 18 Jul 2023 16:40:21 -0700 [thread overview]
Message-ID: <20230718234021.43640-1-alexei.starovoitov@gmail.com> (raw)
From: Alexei Starovoitov <ast@kernel.org>
Network drivers always call skb_header_pointer() with non-null buffer.
Remove !buffer check to prevent accidental misuse of skb_header_pointer().
Introduce skb_pointer_if_linear() instead.
Reported-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
include/linux/skbuff.h | 10 +++++++++-
kernel/bpf/helpers.c | 5 ++++-
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 91ed66952580..f276d0e9816f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -4023,7 +4023,7 @@ __skb_header_pointer(const struct sk_buff *skb, int offset, int len,
if (likely(hlen - offset >= len))
return (void *)data + offset;
- if (!skb || !buffer || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0))
+ if (!skb || unlikely(skb_copy_bits(skb, offset, buffer, len) < 0))
return NULL;
return buffer;
@@ -4036,6 +4036,14 @@ skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer)
skb_headlen(skb), buffer);
}
+static inline void * __must_check
+skb_pointer_if_linear(const struct sk_buff *skb, int offset, int len)
+{
+ if (likely(skb_headlen(skb) - offset >= len))
+ return skb->data + offset;
+ return NULL;
+}
+
/**
* skb_needs_linearize - check if we need to linearize a given skb
* depending on the given device features.
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 9e80efa59a5d..b8ab3bea71b7 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2239,7 +2239,10 @@ __bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset
case BPF_DYNPTR_TYPE_RINGBUF:
return ptr->data + ptr->offset + offset;
case BPF_DYNPTR_TYPE_SKB:
- return skb_header_pointer(ptr->data, ptr->offset + offset, len, buffer__opt);
+ if (buffer__opt)
+ return skb_header_pointer(ptr->data, ptr->offset + offset, len, buffer__opt);
+ else
+ return skb_pointer_if_linear(ptr->data, ptr->offset + offset, len);
case BPF_DYNPTR_TYPE_XDP:
{
void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset + offset, len);
--
2.34.1
next reply other threads:[~2023-07-18 23:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-18 23:40 Alexei Starovoitov [this message]
2023-07-19 13:10 ` [PATCH bpf-next] bpf, net: Introduce skb_pointer_if_linear() David Laight
2023-07-19 16:30 ` Alexei Starovoitov
2023-07-19 17:20 ` Jakub Kicinski
2023-07-19 17:40 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230718234021.43640-1-alexei.starovoitov@gmail.com \
--to=alexei.starovoitov@gmail.com \
--cc=andrii@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=kernel-team@fb.com \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).