sctp: fix memleak on err handling of stream initialization

[ 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@syzkaller.appspotmail.com
Fixes: 2075e50caf5e ("sctp: convert to genradix")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/sctp/stream.c b/net/sctp/stream.c
index e83cdaa2ab765c1ce20392b5ba2d91573f39ff14..6a30392068a04bfcefcb14c3d7f13fc092d59cd3 100644 (file)
--- a/net/sctp/stream.c
+++ b/net/sctp/stream.c
@@ -84,8 +84,10 @@ static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,
                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 sctp_stream *stream, __u16 incnt,
                return 0;
 
        ret = genradix_prealloc(&stream->in, incnt, gfp);
-       if (ret)
+       if (ret) {
+               genradix_free(&stream->in);
                return ret;
+       }
 
        stream->incnt = incnt;
        return 0;