diff options
| author | Eric Biggers <ebiggers@google.com> | 2017-03-23 13:39:46 -0700 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2017-03-24 21:51:34 +0800 |
| commit | 7850b58ce111818befca6f2975adb7c559caa461 (patch) | |
| tree | 7ca636ddf578e37425761e50526b1c56faee3316 /crypto/xts.c | |
| parent | 4c6427919ee920d5963cf826de76292286342aa0 (diff) | |
| download | linux-crypto-7850b58ce111818befca6f2975adb7c559caa461.tar.gz linux-crypto-7850b58ce111818befca6f2975adb7c559caa461.zip | |
crypto: xts,lrw - fix out-of-bounds write after kmalloc failure
In the generic XTS and LRW algorithms, for input data > 128 bytes, a
temporary buffer is allocated to hold the values to be XOR'ed with the
data before and after encryption or decryption. If the allocation
fails, the fixed-size buffer embedded in the request buffer is meant to
be used as a fallback --- resulting in more calls to the ECB algorithm,
but still producing the correct result. However, we weren't correctly
limiting subreq->cryptlen in this case, resulting in pre_crypt()
overrunning the embedded buffer. Fix this by setting subreq->cryptlen
correctly.
Fixes: 6c1314f521f2 ("crypto: xts - Convert to skcipher")
Fixes: f96ee41be16a ("crypto: lrw - Convert to skcipher")
Cc: stable@vger.kernel.org # v4.10+
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/xts.c')
| -rw-r--r-- | crypto/xts.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/crypto/xts.c b/crypto/xts.c index baeb34dd..c976bfac 100644 --- a/crypto/xts.c +++ b/crypto/xts.c @@ -230,8 +230,11 @@ static int init_crypt(struct skcipher_request *req, crypto_completion_t done) subreq->cryptlen = XTS_BUFFER_SIZE; if (req->cryptlen > XTS_BUFFER_SIZE) { - subreq->cryptlen = min(req->cryptlen, (unsigned)PAGE_SIZE); - rctx->ext = kmalloc(subreq->cryptlen, gfp); + unsigned int n = min(req->cryptlen, (unsigned int)PAGE_SIZE); + + rctx->ext = kmalloc(n, gfp); + if (rctx->ext) + subreq->cryptlen = n; } rctx->src = req->src; |