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| 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 | 9df0eb180c2074451f25556eb566d89c7057c2ac (patch) | |
| tree | 493dfd3286e9d96b9c9ae42956136a4e9a7b5fb9 | |
| parent | efc989fce8703914bac091dcc4b8ff7a72ccf987 (diff) | |
| download | linux-9df0eb180c2074451f25556eb566d89c7057c2ac.tar.gz linux-9df0eb180c2074451f25556eb566d89c7057c2ac.tar.bz2 linux-9df0eb180c2074451f25556eb566d89c7057c2ac.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: f1c131b45410 ("crypto: xts - Convert to skcipher")
Fixes: 700cb3f5fe75 ("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>
| -rw-r--r-- | crypto/lrw.c | 7 | ||||
| -rw-r--r-- | crypto/xts.c | 7 |
2 files changed, 10 insertions, 4 deletions
diff --git a/crypto/lrw.c b/crypto/lrw.c index ecd8474018e3..3ea095adafd9 100644 --- a/crypto/lrw.c +++ b/crypto/lrw.c @@ -286,8 +286,11 @@ static int init_crypt(struct skcipher_request *req, crypto_completion_t done) subreq->cryptlen = LRW_BUFFER_SIZE; if (req->cryptlen > LRW_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; diff --git a/crypto/xts.c b/crypto/xts.c index baeb34dd8582..c976bfac29da 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; |