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udp: fix skb_copy_and_csum_datagram with odd segment sizes

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When iteratively computing a checksum with csum_block_add, track the
offset "pos" to correctly rotate in csum_block_add when offset is odd.

The open coded implementation of skb_copy_and_csum_datagram did this.
With the switch to __skb_datagram_iter calling csum_and_copy_to_iter,
pos was reinitialized to 0 on each call.

Bring back the pos by passing it along with the csum to the callback.

Changes v1->v2
  - pass csum value, instead of csump pointer (Alexander Duyck)

Link: https://lore.kernel.org/netdev/20210128152353.GB27281@optiplex/
Fixes: 950fcaecd5 ("datagram: consolidate datagram copy to iter helpers")
Reported-by: Oliver Graute <oliver.graute@gmail.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20210203192952.1849843-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Willem de Bruijn 2021-02-03 14:29:52 -05:00 committed by Jakub Kicinski
parent 1d23a56b02
commit 52cbd23a11
3 changed files with 31 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
include/linux/uio.h
View File

@ -260,7 +260,13 @@ static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
{
i->count = count;
}
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump, struct iov_iter *i);
struct csum_state {
__wsum csum;
size_t off;
};
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,

24
lib/iov_iter.c
View File

@ -592,14 +592,15 @@ static __wsum csum_and_memcpy(void *to, const void *from, size_t len,
}
static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes,
__wsum *csum, struct iov_iter *i)
struct csum_state *csstate,
struct iov_iter *i)
{
struct pipe_inode_info *pipe = i->pipe;
unsigned int p_mask = pipe->ring_size - 1;
__wsum sum = csstate->csum;
size_t off = csstate->off;
unsigned int i_head;
size_t n, r;
size_t off = 0;
__wsum sum = *csum;
if (!sanity(i))
return 0;
@ -621,7 +622,8 @@ static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes,
i_head++;
} while (n);
i->count -= bytes;
*csum = sum;
csstate->csum = sum;
csstate->off = off;
return bytes;
}
@ -1522,18 +1524,19 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
}
EXPORT_SYMBOL(csum_and_copy_from_iter_full);
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump,
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
struct iov_iter *i)
{
struct csum_state *csstate = _csstate;
const char *from = addr;
__wsum *csum = csump;
__wsum sum, next;
size_t off = 0;
size_t off;
if (unlikely(iov_iter_is_pipe(i)))
return csum_and_copy_to_pipe_iter(addr, bytes, csum, i);
return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i);
sum = *csum;
sum = csstate->csum;
off = csstate->off;
if (unlikely(iov_iter_is_discard(i))) {
WARN_ON(1); /* for now */
return 0;
@ -1561,7 +1564,8 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csump,
off += v.iov_len;
})
)
*csum = sum;
csstate->csum = sum;
csstate->off = off;
return bytes;
}
EXPORT_SYMBOL(csum_and_copy_to_iter);

12
net/core/datagram.c
View File

@ -721,8 +721,16 @@ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset,
struct iov_iter *to, int len,
__wsum *csump)
{
return __skb_datagram_iter(skb, offset, to, len, true,
csum_and_copy_to_iter, csump);
struct csum_state csdata = { .csum = *csump };
int ret;
ret = __skb_datagram_iter(skb, offset, to, len, true,
csum_and_copy_to_iter, &csdata);
if (ret)
return ret;
*csump = csdata.csum;
return 0;
}
/**