[PATCH 5.7 099/204] crypto: algif_aead - Only wake up when ctx->more is zero

Greg Kroah-Hartman
2020-08-20T09:39:25Z

From: Herbert Xu <herbert@gondor.apana.org.au>

[ Upstream commit f3c802a1f30013f8f723b62d7fa49eb9e991da23 ]

AEAD does not support partial requests so we must not wake up
while ctx->more is set. In order to distinguish between the
case of no data sent yet and a zero-length request, a new init
flag has been added to ctx.

SKCIPHER has also been modified to ensure that at least a block
of data is available if there is more data to come.

Fixes: 2d97591ef43d ("crypto: af_alg - consolidation of...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
crypto/af_alg.c | 11 ++++++++---
crypto/algif_aead.c | 4 ++--
crypto/algif_skcipher.c | 4 ++--
include/crypto/if_alg.h | 4 +++-
4 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 28fc323e3fe30..9fcb91ea10c41 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -635,6 +635,7 @@ void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,

if (!ctx->used)
ctx->merge = 0;
+ ctx->init = ctx->more;
}
EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);

@@ -734,9 +735,10 @@ EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
*
* @sk socket of connection to user space
* @flags If MSG_DONTWAIT is set, then only report if function would sleep
+ * @min Set to minimum request size if partial requests are allowed.
* @return 0 when writable memory is available, < 0 upon error
*/
-int af_alg_wait_for_data(struct sock *sk, unsigned flags)
+int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
{
DEFINE_WAIT_FUNC(wait, woken_wake_function);
struct alg_sock *ask = alg_sk(sk);
@@ -754,7 +756,9 @@ int af_alg_wait_for_data(struct sock *sk, unsigned flags)
if (signal_pending(current))
break;
timeout = MAX_SCHEDULE_TIMEOUT;
- if (sk_wait_event(sk, &timeout, (ctx->used || !ctx->more),
+ if (sk_wait_event(sk, &timeout,
+ ctx->init && (!ctx->more ||
+ (min && ctx->used >= min)),
&wait)) {
err = 0;
break;
@@ -843,7 +847,7 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
}

lock_sock(sk);
- if (!ctx->more && ctx->used) {
+ if (ctx->init && (init || !ctx->more)) {
err = -EINVAL;
goto unlock;
}
@@ -854,6 +858,7 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
memcpy(ctx->iv, con.iv->iv, ivsize);

ctx->aead_assoclen = con.aead_assoclen;
+ ctx->init = true;
}

while (size) {
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 0ae000a61c7f5..d48d2156e6210 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -106,8 +106,8 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
size_t usedpages = 0; /* [in] RX bufs to be used from user */
size_t processed = 0; /* [in] TX bufs to be consumed */

- if (!ctx->used) {
- err = af_alg_wait_for_data(sk, flags);
+ if (!ctx->init || ctx->more) {
+ err = af_alg_wait_for_data(sk, flags, 0);
if (err)
return err;
}
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index ec5567c87a6df..a51ba22fef58f 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -61,8 +61,8 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
int err = 0;
size_t len = 0;

- if (!ctx->used) {
- err = af_alg_wait_for_data(sk, flags);
+ if (!ctx->init || (ctx->more && ctx->used < bs)) {
+ err = af_alg_wait_for_data(sk, flags, bs);
if (err)
return err;
}
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 088c1ded27148..ee6412314f8f3 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -135,6 +135,7 @@ struct af_alg_async_req {
* SG?
* @enc: Cryptographic operation to be performed when
* recvmsg is invoked.
+ * @init: True if metadata has been sent.
* @len: Length of memory allocated for this data structure.
*/
struct af_alg_ctx {
@@ -151,6 +152,7 @@ struct af_alg_ctx {
bool more;
bool merge;
bool enc;
+ bool init;

unsigned int len;
};
@@ -226,7 +228,7 @@ unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
size_t dst_offset);
void af_alg_wmem_wakeup(struct sock *sk);
-int af_alg_wait_for_data(struct sock *sk, unsigned flags);
+int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min);
int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
unsigned int ivsize);
ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
--
2.25.1