4.10-stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Biggers <[email protected]> commit 9df0eb180c2074451f25556eb566d89c7057c2ac upstream. 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") Reported-by: Dmitry Vyukov <[email protected]> Signed-off-by: Eric Biggers <[email protected]> Acked-by: David S. Miller <[email protected]> Signed-off-by: Herbert Xu <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- crypto/lrw.c | 7 +++++-- crypto/xts.c | 7 +++++-- 2 files changed, 10 insertions(+), 4 deletions(-) --- a/crypto/lrw.c +++ b/crypto/lrw.c @@ -286,8 +286,11 @@ static int init_crypt(struct skcipher_re 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; --- a/crypto/xts.c +++ b/crypto/xts.c @@ -230,8 +230,11 @@ static int init_crypt(struct skcipher_re 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;
