[PATCH v6 16/18] rxrpc: Reuse SKCIPHER_REQUEST_ON_STACK buffer

Kees Cook
2018-07-24T16:49:34Z

The use of SKCIPHER_REQUEST_ON_STACK() will trigger FRAME_WARN warnings
(when less than 2048) once the VLA is no longer hidden from the check:

net/rxrpc/rxkad.c:398:1: warning: the frame size of 1152 bytes is larger than 1024 bytes [-Wframe-larger-than=]
net/rxrpc/rxkad.c:242:1: warning: the frame size of 1152 bytes is larger than 1024 bytes [-Wframe-larger-than=]

This passes the initial SKCIPHER_REQUEST_ON_STACK allocation to the leaf
functions for reuse. Two requests allocated on the stack is not needed
when only one is used at a time.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
net/rxrpc/rxkad.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 278ac0807a60..6393391fac86 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -146,10 +146,10 @@ static int rxkad_prime_packet_security(struct rxrpc_connection *conn)
static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
struct sk_buff *skb,
u32 data_size,
- void *sechdr)
+ void *sechdr,
+ struct skcipher_request *req)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
- SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxkad_level1_hdr hdr;
struct rxrpc_crypt iv;
struct scatterlist sg;
@@ -183,12 +183,12 @@ static int rxkad_secure_packet_auth(const struct rxrpc_call *call,
static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,
struct sk_buff *skb,
u32 data_size,
- void *sechdr)
+ void *sechdr,
+ struct skcipher_request *req)
{
const struct rxrpc_key_token *token;
struct rxkad_level2_hdr rxkhdr;
struct rxrpc_skb_priv *sp;
- SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist sg[16];
struct sk_buff *trailer;
@@ -296,11 +296,12 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
ret = 0;
break;
case RXRPC_SECURITY_AUTH:
- ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr);
+ ret = rxkad_secure_packet_auth(call, skb, data_size, sechdr,
+ req);
break;
case RXRPC_SECURITY_ENCRYPT:
ret = rxkad_secure_packet_encrypt(call, skb, data_size,
- sechdr);
+ sechdr, req);
break;
default:
ret = -EPERM;
@@ -316,10 +317,10 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
*/
static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
unsigned int offset, unsigned int len,
- rxrpc_seq_t seq)
+ rxrpc_seq_t seq,
+ struct skcipher_request *req)
{
struct rxkad_level1_hdr sechdr;
- SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist sg[16];
struct sk_buff *trailer;
@@ -402,11 +403,11 @@ static int rxkad_verify_packet_1(struct rxrpc_call *call, struct sk_buff *skb,
*/
static int rxkad_verify_packet_2(struct rxrpc_call *call, struct sk_buff *skb,
unsigned int offset, unsigned int len,
- rxrpc_seq_t seq)
+ rxrpc_seq_t seq,
+ struct skcipher_request *req)
{
const struct rxrpc_key_token *token;
struct rxkad_level2_hdr sechdr;
- SKCIPHER_REQUEST_ON_STACK(req, call->conn->cipher);
struct rxrpc_crypt iv;
struct scatterlist _sg[4], *sg;
struct sk_buff *trailer;
@@ -549,9 +550,9 @@ static int rxkad_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
case RXRPC_SECURITY_PLAIN:
return 0;
case RXRPC_SECURITY_AUTH:
- return rxkad_verify_packet_1(call, skb, offset, len, seq);
+ return rxkad_verify_packet_1(call, skb, offset, len, seq, req);
case RXRPC_SECURITY_ENCRYPT:
- return rxkad_verify_packet_2(call, skb, offset, len, seq);
+ return rxkad_verify_packet_2(call, skb, offset, len, seq, req);
default:
return -ENOANO;
}
--
2.17.1