Patch "sctp: make use of pre-calculated len" has been added to the 4.4-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    sctp: make use of pre-calculated len

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     sctp-make-use-of-pre-calculated-len.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From foo@baz Wed Feb 28 16:19:30 CET 2018
From: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Date: Mon, 8 Jan 2018 19:02:29 -0200
Subject: sctp: make use of pre-calculated len

From: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>


[ Upstream commit c76f97c99ae6d26d14c7f0e50e074382bfbc9f98 ]

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@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/sctp/socket.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4445,7 +4445,7 @@ static int sctp_getsockopt_autoclose(str
 	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;
 }
@@ -5022,6 +5022,9 @@ copy_getaddrs:
 		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:
@@ -5458,7 +5461,7 @@ static int sctp_getsockopt_maxseg(struct
 		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;
@@ -5627,7 +5630,9 @@ static int sctp_getsockopt_active_key(st
 
 	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);
@@ -5639,7 +5644,6 @@ static int sctp_getsockopt_active_key(st
 	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))
@@ -5665,7 +5669,7 @@ static int sctp_getsockopt_peer_auth_chu
 	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;
@@ -5710,7 +5714,7 @@ static int sctp_getsockopt_local_auth_ch
 	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;


Patches currently in stable-queue which might be from marcelo.leitner@xxxxxxxxx are

queue-4.4/sctp-make-use-of-pre-calculated-len.patch