diff options
| author | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2021-12-01 21:54:52 +0300 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2021-12-07 19:05:38 +0300 |
| commit | 13244cccc2b61ec715f0ac583d3037497004d4a5 (patch) | |
| tree | a6f62154833573b637d1ce75ac7ca99b88311da2 | |
| parent | 561ae1d46a8ddcbc13162d5771f5ed6c8249e730 (diff) | |
| download | linux-13244cccc2b61ec715f0ac583d3037497004d4a5.tar.xz | |
skbuff: introduce skb_pull_data
Like skb_pull but returns the original data pointer before pulling the
data after performing a check against sbk->len.
This allows to change code that does "struct foo *p = (void *)skb->data;"
which is hard to audit and error prone, to:
p = skb_pull_data(skb, sizeof(*p));
if (!p)
return;
Which is both safer and cleaner.
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
| -rw-r--r-- | include/linux/skbuff.h | 2 | ||||
| -rw-r--r-- | net/core/skbuff.c | 24 |
2 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index eba256af64a5..877dda38684a 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2373,6 +2373,8 @@ static inline void *skb_pull_inline(struct sk_buff *skb, unsigned int len) return unlikely(len > skb->len) ? NULL : __skb_pull(skb, len); } +void *skb_pull_data(struct sk_buff *skb, size_t len); + void *__pskb_pull_tail(struct sk_buff *skb, int delta); static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a33247fdb8f5..dd3ef966efdb 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2024,6 +2024,30 @@ void *skb_pull(struct sk_buff *skb, unsigned int len) EXPORT_SYMBOL(skb_pull); /** + * skb_pull_data - remove data from the start of a buffer returning its + * original position. + * @skb: buffer to use + * @len: amount of data to remove + * + * This function removes data from the start of a buffer, returning + * the memory to the headroom. A pointer to the original data in the buffer + * is returned after checking if there is enough data to pull. Once the + * data has been pulled future pushes will overwrite the old data. + */ +void *skb_pull_data(struct sk_buff *skb, size_t len) +{ + void *data = skb->data; + + if (skb->len < len) + return NULL; + + skb_pull(skb, len); + + return data; +} +EXPORT_SYMBOL(skb_pull_data); + +/** * skb_trim - remove end from a buffer * @skb: buffer to alter * @len: new length |