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

Greg Kroah-Hartman
2019-12-29T17:42:00Z

From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.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@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>
---
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;