commit c76f97c99ae6d26d14c7f0e50e074382bfbc9f98
author Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Mon Jan 08 19:02:29 2018 -0200
committer David S. Miller <davem@davemloft.net> Wed Jan 10 14:53:22 2018 -0500
tree da82823b2b3fa04568f7ab98c984476728ea6cbc
parent 5960cefab9df76600a1a7d4ff592c59e14616e88

sctp: make use of pre-calculated len

Some sockopt handling functions were calculating the length of the
buffer to be written to userspace and then calculating it again when
actually writing the buffer, which could lead to some write not using
an up-to-date length.

This patch updates such places to just make use of the len variable.

Also, replace some sizeof(type) to sizeof(var).

Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 022b94f..9b01e99 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5025,7 +5025,7 @@
 	len = sizeof(int);
 	if (put_user(len, optlen))
 		return -EFAULT;
-	if (copy_to_user(optval, &sctp_sk(sk)->autoclose, sizeof(int)))
+	if (copy_to_user(optval, &sctp_sk(sk)->autoclose, len))
 		return -EFAULT;
 	return 0;
 }
@@ -5655,6 +5655,9 @@
 		err = -EFAULT;
 		goto out;
 	}
+	/* XXX: We should have accounted for sizeof(struct sctp_getaddrs) too,
+	 * but we can't change it anymore.
+	 */
 	if (put_user(bytes_copied, optlen))
 		err = -EFAULT;
 out:
@@ -6091,7 +6094,7 @@
 		params.assoc_id = 0;
 	} else if (len >= sizeof(struct sctp_assoc_value)) {
 		len = sizeof(struct sctp_assoc_value);
-		if (copy_from_user(&params, optval, sizeof(params)))
+		if (copy_from_user(&params, optval, len))
 			return -EFAULT;
 	} else
 		return -EINVAL;
@@ -6261,7 +6264,9 @@
 
 	if (len < sizeof(struct sctp_authkeyid))
 		return -EINVAL;
-	if (copy_from_user(&val, optval, sizeof(struct sctp_authkeyid)))
+
+	len = sizeof(struct sctp_authkeyid);
+	if (copy_from_user(&val, optval, len))
 		return -EFAULT;
 
 	asoc = sctp_id2assoc(sk, val.scact_assoc_id);
@@ -6273,7 +6278,6 @@
 	else
 		val.scact_keynumber = ep->active_key_id;
 
-	len = sizeof(struct sctp_authkeyid);
 	if (put_user(len, optlen))
 		return -EFAULT;
 	if (copy_to_user(optval, &val, len))
@@ -6299,7 +6303,7 @@
 	if (len < sizeof(struct sctp_authchunks))
 		return -EINVAL;
 
-	if (copy_from_user(&val, optval, sizeof(struct sctp_authchunks)))
+	if (copy_from_user(&val, optval, sizeof(val)))
 		return -EFAULT;
 
 	to = p->gauth_chunks;
@@ -6344,7 +6348,7 @@
 	if (len < sizeof(struct sctp_authchunks))
 		return -EINVAL;
 
-	if (copy_from_user(&val, optval, sizeof(struct sctp_authchunks)))
+	if (copy_from_user(&val, optval, sizeof(val)))
 		return -EFAULT;
 
 	to = p->gauth_chunks;