Re: GPF in lrw_crypt
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: 2015-12-24 09:39:25
Also in:
lkml
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
On Thu, Dec 17, 2015 at 01:59:11PM +0100, Dmitry Vyukov wrote:
The following program causes GPF in lrw_crypt:
OK, this is a result of certain implementations (such as lrw) not coping with there being no key gracefully. I think the easiest way is probably to check this in algif_skcipher. ---8<--- Subject: crypto: algif_skcipher - Require setkey before accept(2) Some cipher implementations will crash if you try to use them without calling setkey first. This patch adds a check so that the accept(2) call will fail with -ENOKEY if setkey hasn't been done on the socket yet. Cc: stable@vger.kernel.org Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 5c756b3..b62c973 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c@@ -31,6 +31,11 @@ struct skcipher_sg_list { struct scatterlist sg[0]; }; +struct skcipher_tfm { + struct crypto_skcipher *skcipher; + bool has_key; +}; + struct skcipher_ctx { struct list_head tsgl; struct af_alg_sgl rsgl;
@@ -750,17 +755,38 @@ static struct proto_ops algif_skcipher_ops = { static void *skcipher_bind(const char *name, u32 type, u32 mask) { - return crypto_alloc_skcipher(name, type, mask); + struct skcipher_tfm *tfm; + + tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); + if (!tfm) + return ERR_PTR(-ENOMEM); + + tfm->skcipher = crypto_alloc_skcipher(name, type, mask); + if (IS_ERR(tfm->skcipher)) { + kfree(tfm); + return ERR_CAST(tfm->skcipher); + } + + return tfm; } static void skcipher_release(void *private) { - crypto_free_skcipher(private); + struct skcipher_tfm *tfm = private; + + crypto_free_skcipher(tfm->skcipher); + kfree(tfm); } static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen) { - return crypto_skcipher_setkey(private, key, keylen); + struct skcipher_tfm *tfm = private; + int err; + + err = crypto_skcipher_setkey(tfm->skcipher, key, keylen); + tfm->has_key = !err; + + return err; } static void skcipher_wait(struct sock *sk)
@@ -792,20 +818,25 @@ static int skcipher_accept_parent(void *private, struct sock *sk) { struct skcipher_ctx *ctx; struct alg_sock *ask = alg_sk(sk); - unsigned int len = sizeof(*ctx) + crypto_skcipher_reqsize(private); + struct skcipher_tfm *tfm = private; + struct crypto_skcipher *skcipher = tfm->skcipher; + unsigned int len = sizeof(*ctx) + crypto_skcipher_reqsize(skcipher); + + if (!tfm->has_key) + return -ENOKEY; ctx = sock_kmalloc(sk, len, GFP_KERNEL); if (!ctx) return -ENOMEM; - ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(private), + ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(skcipher), GFP_KERNEL); if (!ctx->iv) { sock_kfree_s(sk, ctx, len); return -ENOMEM; } - memset(ctx->iv, 0, crypto_skcipher_ivsize(private)); + memset(ctx->iv, 0, crypto_skcipher_ivsize(skcipher)); INIT_LIST_HEAD(&ctx->tsgl); ctx->len = len;
@@ -818,7 +849,7 @@ static int skcipher_accept_parent(void *private, struct sock *sk) ask->private = ctx; - skcipher_request_set_tfm(&ctx->req, private); + skcipher_request_set_tfm(&ctx->req, skcipher); skcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, af_alg_complete, &ctx->completion);
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt