diff options
author | Carl Huang <cjhuang@codeaurora.org> | 2020-01-03 07:50:16 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-03-20 13:55:59 +0300 |
commit | bc97a345d97556dea71f0748acb5d9ea413c7cc7 (patch) | |
tree | 9d20160b4dbc32e2d2d81bd1ca19ba4f02ce71fc /net | |
parent | cda3bca05e2ccd8177197328cf32d868f063c2d2 (diff) | |
download | linux-bc97a345d97556dea71f0748acb5d9ea413c7cc7.tar.xz |
net: qrtr: fix len of skb_put_padto in qrtr_node_enqueue
commit ce57785bf91b1ceaef4f4bffed8a47dc0919c8da upstream.
The len used for skb_put_padto is wrong, it need to add len of hdr.
In qrtr_node_enqueue, local variable size_t len is assign with
skb->len, then skb_push(skb, sizeof(*hdr)) will add skb->len with
sizeof(*hdr), so local variable size_t len is not same with skb->len
after skb_push(skb, sizeof(*hdr)).
Then the purpose of skb_put_padto(skb, ALIGN(len, 4)) is to add add
pad to the end of the skb's data if skb->len is not aligned to 4, but
unfortunately it use len instead of skb->len, at this line, skb->len
is 32 bytes(sizeof(*hdr)) more than len, for example, len is 3 bytes,
then skb->len is 35 bytes(3 + 32), and ALIGN(len, 4) is 4 bytes, so
__skb_put_padto will do nothing after check size(35) < len(4), the
correct value should be 36(sizeof(*hdr) + ALIGN(len, 4) = 32 + 4),
then __skb_put_padto will pass check size(35) < len(36) and add 1 byte
to the end of skb's data, then logic is correct.
function of skb_push:
void *skb_push(struct sk_buff *skb, unsigned int len)
{
skb->data -= len;
skb->len += len;
if (unlikely(skb->data < skb->head))
skb_under_panic(skb, len, __builtin_return_address(0));
return skb->data;
}
function of skb_put_padto
static inline int skb_put_padto(struct sk_buff *skb, unsigned int len)
{
return __skb_put_padto(skb, len, true);
}
function of __skb_put_padto
static inline int __skb_put_padto(struct sk_buff *skb, unsigned int len,
bool free_on_error)
{
unsigned int size = skb->len;
if (unlikely(size < len)) {
len -= size;
if (__skb_pad(skb, len, free_on_error))
return -ENOMEM;
__skb_put(skb, len);
}
return 0;
}
Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
Signed-off-by: Wen Gong <wgong@codeaurora.org>
Cc: Doug Anderson <dianders@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r-- | net/qrtr/qrtr.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c index 5c75118539bb..82d38f93c81a 100644 --- a/net/qrtr/qrtr.c +++ b/net/qrtr/qrtr.c @@ -203,7 +203,7 @@ static int qrtr_node_enqueue(struct qrtr_node *node, struct sk_buff *skb, hdr->size = cpu_to_le32(len); hdr->confirm_rx = 0; - skb_put_padto(skb, ALIGN(len, 4)); + skb_put_padto(skb, ALIGN(len, 4) + sizeof(*hdr)); mutex_lock(&node->ep_lock); if (node->ep) |