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| author | Tom Lendacky <thomas.lendacky@amd.com> | 2015-06-01 11:15:53 -0500 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2015-06-03 10:51:28 +0800 |
| commit | fb43f69401fef8ed2f72d7ea4a25910a0f2138bc (patch) | |
| tree | d7402f0cffb4e46314c6861df7408b077a6a56cc /drivers/crypto/ccp | |
| parent | cfaed10d1f27d036b72bbdc6b1e59ea28c38ec7f (diff) | |
| download | linux-fb43f69401fef8ed2f72d7ea4a25910a0f2138bc.tar.bz2 | |
crypto: ccp - Protect against poorly marked end of sg list
Scatter gather lists can be created with more available entries than are
actually used (e.g. using sg_init_table() to reserve a specific number
of sg entries, but in actuality using something less than that based on
the data length). The caller sometimes fails to mark the last entry
with sg_mark_end(). In these cases, sg_nents() will return the original
size of the sg list as opposed to the actual number of sg entries that
contain valid data.
On arm64, if the sg_nents() value is used in a call to dma_map_sg() in
this situation, then it causes a BUG_ON in lib/swiotlb.c because an
"empty" sg list entry results in dma_capable() returning false and
swiotlb trying to create a bounce buffer of size 0. This occurred in
the userspace crypto interface before being fixed by
0f477b655a52 ("crypto: algif - Mark sgl end at the end of data")
Protect against this by using the new sg_nents_for_len() function which
returns only the number of sg entries required to meet the desired
length and supplying that value to dma_map_sg().
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/crypto/ccp')
| -rw-r--r-- | drivers/crypto/ccp/ccp-ops.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/crypto/ccp/ccp-ops.c b/drivers/crypto/ccp/ccp-ops.c index 542453c9ba1c..d09c6c4af4aa 100644 --- a/drivers/crypto/ccp/ccp-ops.c +++ b/drivers/crypto/ccp/ccp-ops.c @@ -52,7 +52,7 @@ struct ccp_dm_workarea { struct ccp_sg_workarea { struct scatterlist *sg; - unsigned int nents; + int nents; struct scatterlist *dma_sg; struct device *dma_dev; @@ -495,7 +495,10 @@ static int ccp_init_sg_workarea(struct ccp_sg_workarea *wa, struct device *dev, if (!sg) return 0; - wa->nents = sg_nents(sg); + wa->nents = sg_nents_for_len(sg, len); + if (wa->nents < 0) + return wa->nents; + wa->bytes_left = len; wa->sg_used = 0; |