linux-kernel - [PATCH 5.4 015/434] sctp: fix memleak on err handling of stream initialization

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Date:   Sun, 29 Dec 2019 18:21:08 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        syzbot+772d9e36c490b18d51d1@...kaller.appspotmail.com,
        Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
        Xin Long <lucien.xin@...il.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 5.4 015/434] sctp: fix memleak on err handling of stream initialization

From: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>

[ Upstream commit 951c6db954a1adefab492f6da805decacabbd1a7 ]

syzbot reported a memory leak when an allocation fails within
genradix_prealloc() for output streams. That's because
genradix_prealloc() leaves initialized members initialized when the
issue happens and SCTP stack will abort the current initialization but
without cleaning up such members.

The fix here is to always call genradix_free() when genradix_prealloc()
fails, for output and also input streams, as it suffers from the same
issue.

Reported-by: syzbot+772d9e36c490b18d51d1@...kaller.appspotmail.com
Fixes: 2075e50caf5e ("sctp: convert to genradix")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
Tested-by: Xin Long <lucien.xin@...il.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/sctp/stream.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -84,8 +84,10 @@ static int sctp_stream_alloc_out(struct
 		return 0;
 
 	ret = genradix_prealloc(&stream->out, outcnt, gfp);
-	if (ret)
+	if (ret) {
+		genradix_free(&stream->out);
 		return ret;
+	}
 
 	stream->outcnt = outcnt;
 	return 0;
@@ -100,8 +102,10 @@ static int sctp_stream_alloc_in(struct s
 		return 0;
 
 	ret = genradix_prealloc(&stream->in, incnt, gfp);
-	if (ret)
+	if (ret) {
+		genradix_free(&stream->in);
 		return ret;
+	}
 
 	stream->incnt = incnt;
 	return 0;