From b02989f37fc5e865ceeee9070907e4493b3a21e2 Mon Sep 17 00:00:00 2001 From: "Longpeng(Mike)" Date: Tue, 2 Jun 2020 15:04:59 +0800 Subject: crypto: virtio: Fix src/dst scatterlist calculation in __virtio_crypto_skcipher_do_req() The system will crash when the users insmod crypto/tcrypt.ko with mode=38 ( testing "cts(cbc(aes))" ). Usually the next entry of one sg will be @sg@ + 1, but if this sg element is part of a chained scatterlist, it could jump to the start of a new scatterlist array. Fix it by sg_next() on calculation of src/dst scatterlist. Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver") Reported-by: LABBE Corentin Cc: Herbert Xu Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: "David S. Miller" Cc: virtualization@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200123101000.GB24255@Red Signed-off-by: Gonglei Signed-off-by: Longpeng(Mike) Link: https://lore.kernel.org/r/20200602070501.2023-2-longpeng2@huawei.com Signed-off-by: Michael S. Tsirkin --- drivers/crypto/virtio/virtio_crypto_algs.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'drivers/crypto') diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c index fd045e64972a..5f8243563009 100644 --- a/drivers/crypto/virtio/virtio_crypto_algs.c +++ b/drivers/crypto/virtio/virtio_crypto_algs.c @@ -350,13 +350,18 @@ __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req, int err; unsigned long flags; struct scatterlist outhdr, iv_sg, status_sg, **sgs; - int i; u64 dst_len; unsigned int num_out = 0, num_in = 0; int sg_total; uint8_t *iv; + struct scatterlist *sg; src_nents = sg_nents_for_len(req->src, req->cryptlen); + if (src_nents < 0) { + pr_err("Invalid number of src SG.\n"); + return src_nents; + } + dst_nents = sg_nents(req->dst); pr_debug("virtio_crypto: Number of sgs (src_nents: %d, dst_nents: %d)\n", @@ -442,12 +447,12 @@ __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req, vc_sym_req->iv = iv; /* Source data */ - for (i = 0; i < src_nents; i++) - sgs[num_out++] = &req->src[i]; + for (sg = req->src; src_nents; sg = sg_next(sg), src_nents--) + sgs[num_out++] = sg; /* Destination data */ - for (i = 0; i < dst_nents; i++) - sgs[num_out + num_in++] = &req->dst[i]; + for (sg = req->dst; sg; sg = sg_next(sg)) + sgs[num_out + num_in++] = sg; /* Status */ sg_init_one(&status_sg, &vc_req->status, sizeof(vc_req->status)); -- cgit v1.2.3 From 8c855f0720ff006d75d0a2512c7f6c4f60ff60ee Mon Sep 17 00:00:00 2001 From: "Longpeng(Mike)" Date: Tue, 2 Jun 2020 15:05:00 +0800 Subject: crypto: virtio: Fix use-after-free in virtio_crypto_skcipher_finalize_req() The system'll crash when the users insmod crypto/tcrypto.ko with mode=155 ( testing "authenc(hmac(sha1),cbc(aes))" ). It's caused by reuse the memory of request structure. In crypto_authenc_init_tfm(), the reqsize is set to: [PART 1] sizeof(authenc_request_ctx) + [PART 2] ictx->reqoff + [PART 3] MAX(ahash part, skcipher part) and the 'PART 3' is used by both ahash and skcipher in turn. When the virtio_crypto driver finish skcipher req, it'll call ->complete callback(in crypto_finalize_skcipher_request) and then free its resources whose pointers are recorded in 'skcipher parts'. However, the ->complete is 'crypto_authenc_encrypt_done' in this case, it will use the 'ahash part' of the request and change its content, so virtio_crypto driver will get the wrong pointer after ->complete finish and mistakenly free some other's memory. So the system will crash when these memory will be used again. The resources which need to be cleaned up are not used any more. But the pointers of these resources may be changed in the function "crypto_finalize_skcipher_request". Thus release specific resources before calling this function. Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver") Reported-by: LABBE Corentin Cc: Gonglei Cc: Herbert Xu Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: "David S. Miller" Cc: virtualization@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200123101000.GB24255@Red Acked-by: Gonglei Signed-off-by: Longpeng(Mike) Link: https://lore.kernel.org/r/20200602070501.2023-3-longpeng2@huawei.com Signed-off-by: Michael S. Tsirkin --- drivers/crypto/virtio/virtio_crypto_algs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'drivers/crypto') diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c index 5f8243563009..52261b6c247e 100644 --- a/drivers/crypto/virtio/virtio_crypto_algs.c +++ b/drivers/crypto/virtio/virtio_crypto_algs.c @@ -582,10 +582,11 @@ static void virtio_crypto_skcipher_finalize_req( scatterwalk_map_and_copy(req->iv, req->dst, req->cryptlen - AES_BLOCK_SIZE, AES_BLOCK_SIZE, 0); - crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine, - req, err); kzfree(vc_sym_req->iv); virtcrypto_clear_request(&vc_sym_req->base); + + crypto_finalize_skcipher_request(vc_sym_req->base.dataq->engine, + req, err); } static struct virtio_crypto_algo virtio_crypto_algs[] = { { -- cgit v1.2.3 From d90ca42012db2863a9a30b564a2ace6016594bda Mon Sep 17 00:00:00 2001 From: "Longpeng(Mike)" Date: Tue, 2 Jun 2020 15:05:01 +0800 Subject: crypto: virtio: Fix dest length calculation in __virtio_crypto_skcipher_do_req() The src/dst length is not aligned with AES_BLOCK_SIZE(which is 16) in some testcases in tcrypto.ko. For example, the src/dst length of one of cts(cbc(aes))'s testcase is 17, the crypto_virtio driver will set @src_data_len=16 but @dst_data_len=17 in this case and get a wrong at then end. SRC: pp pp pp pp pp pp pp pp pp pp pp pp pp pp pp pp pp (17 bytes) EXP: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc pp (17 bytes) DST: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 00 (pollute the last bytes) (pp: plaintext cc:ciphertext) Fix this issue by limit the length of dest buffer. Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver") Cc: Gonglei Cc: Herbert Xu Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: "David S. Miller" Cc: virtualization@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Signed-off-by: Longpeng(Mike) Link: https://lore.kernel.org/r/20200602070501.2023-4-longpeng2@huawei.com Signed-off-by: Michael S. Tsirkin --- drivers/crypto/virtio/virtio_crypto_algs.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/crypto') diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c index 52261b6c247e..cb8a6ea2a4bc 100644 --- a/drivers/crypto/virtio/virtio_crypto_algs.c +++ b/drivers/crypto/virtio/virtio_crypto_algs.c @@ -407,6 +407,7 @@ __virtio_crypto_skcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req, goto free; } + dst_len = min_t(unsigned int, req->cryptlen, dst_len); pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n", req->cryptlen, dst_len); -- cgit v1.2.3