crypto: user - no parsing of CRYPTO_MSG_GETALG

The CRYPTO_MSG_GETALG netlink message type provides a buffer to the kernel to retrieve information from the kernel. The data buffer will not provide any input and will not be read. Hence the nlmsg_parse is not applicable to this netlink message type. This patch fixes the following kernel log message when using this netlink interface: netlink: 208 bytes leftover after parsing attributes in process `XXX'. Patch successfully tested with libkcapi from [1] which uses CRYPTO_MSG_GETALG to obtain cipher-specific information from the kernel. [1] http://www.chronox.de/libkcapi.html Signed-off-by: Stephan Mueller <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
TechNexion · May 31, 2016 · eed1e1a · eed1e1a
1 parent 1a445e8
commit eed1e1a
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c
@@ -516,10 +516,12 @@ static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 		return err;
 	}
 
-	err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
-			  crypto_policy);
-	if (err < 0)
-		return err;
+	if (type != (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE)) {
+		err = nlmsg_parse(nlh, crypto_msg_min[type], attrs,
+				  CRYPTOCFGA_MAX, crypto_policy);
+		if (err < 0)
+			return err;
+	}
 
 	if (link->doit == NULL)
 		return -EINVAL;