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authorStephan Mueller <smueller@chronox.de>2017-11-10 11:04:52 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2017-11-24 13:23:36 +0800
commit8e1fa89aa8bc2870009b4486644e4a58f2e2a4f5 (patch)
tree30fc1296d5e3ac84f5f2e6642ad5b172535140b6
parent1d9ddde12e3c9bab7f3d3484eb9446315e3571ca (diff)
download96b-common-8e1fa89aa8bc2870009b4486644e4a58f2e2a4f5.tar.gz
crypto: algif_aead - skip SGL entries with NULL page
The TX SGL may contain SGL entries that are assigned a NULL page. This may happen if a multi-stage AIO operation is performed where the data for each stage is pointed to by one SGL entry. Upon completion of that stage, af_alg_pull_tsgl will assign NULL to the SGL entry. The NULL cipher used to copy the AAD from TX SGL to the destination buffer, however, cannot handle the case where the SGL starts with an SGL entry having a NULL page. Thus, the code needs to advance the start pointer into the SGL to the first non-NULL entry. This fixes a crash visible on Intel x86 32 bit using the libkcapi test suite. Cc: <stable@vger.kernel.org> Fixes: 72548b093ee38 ("crypto: algif_aead - copy AAD from src to dst") Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--crypto/algif_aead.c33
1 files changed, 24 insertions, 9 deletions
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index aacae0837aff..e2068b78993c 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -101,10 +101,10 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
struct aead_tfm *aeadc = pask->private;
struct crypto_aead *tfm = aeadc->aead;
struct crypto_skcipher *null_tfm = aeadc->null_tfm;
- unsigned int as = crypto_aead_authsize(tfm);
+ unsigned int i, as = crypto_aead_authsize(tfm);
struct af_alg_async_req *areq;
- struct af_alg_tsgl *tsgl;
- struct scatterlist *src;
+ struct af_alg_tsgl *tsgl, *tmp;
+ struct scatterlist *rsgl_src, *tsgl_src = NULL;
int err = 0;
size_t used = 0; /* [in] TX bufs to be en/decrypted */
size_t outlen = 0; /* [out] RX bufs produced by kernel */
@@ -178,7 +178,22 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
}
processed = used + ctx->aead_assoclen;
- tsgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl, list);
+ list_for_each_entry_safe(tsgl, tmp, &ctx->tsgl_list, list) {
+ for (i = 0; i < tsgl->cur; i++) {
+ struct scatterlist *process_sg = tsgl->sg + i;
+
+ if (!(process_sg->length) || !sg_page(process_sg))
+ continue;
+ tsgl_src = process_sg;
+ break;
+ }
+ if (tsgl_src)
+ break;
+ }
+ if (processed && !tsgl_src) {
+ err = -EFAULT;
+ goto free;
+ }
/*
* Copy of AAD from source to destination
@@ -194,7 +209,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
*/
/* Use the RX SGL as source (and destination) for crypto op. */
- src = areq->first_rsgl.sgl.sg;
+ rsgl_src = areq->first_rsgl.sgl.sg;
if (ctx->enc) {
/*
@@ -207,7 +222,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
* v v
* RX SGL: AAD || PT || Tag
*/
- err = crypto_aead_copy_sgl(null_tfm, tsgl->sg,
+ err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
areq->first_rsgl.sgl.sg, processed);
if (err)
goto free;
@@ -225,7 +240,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
*/
/* Copy AAD || CT to RX SGL buffer for in-place operation. */
- err = crypto_aead_copy_sgl(null_tfm, tsgl->sg,
+ err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
areq->first_rsgl.sgl.sg, outlen);
if (err)
goto free;
@@ -257,11 +272,11 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
areq->tsgl);
} else
/* no RX SGL present (e.g. authentication only) */
- src = areq->tsgl;
+ rsgl_src = areq->tsgl;
}
/* Initialize the crypto operation */
- aead_request_set_crypt(&areq->cra_u.aead_req, src,
+ aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
areq->first_rsgl.sgl.sg, used, ctx->iv);
aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
aead_request_set_tfm(&areq->cra_u.aead_req, tfm);