Messages in this thread Patch in this message |  | | From | Dominique Martinet <> | Subject | [PATCH 2/2] 9p: clear dangling pointers in p9stat_free | Date | Tue, 28 Aug 2018 00:48:28 +0200 |
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From: Dominique Martinet <dominique.martinet@cea.fr>
p9stat_free is more of a cleanup function than a 'free' function as it only frees the content of the struct; there are chances of use-after-free if it is improperly used (e.g. p9stat_free called twice as it used to be possible to)
Clearing dangling pointers makes the function idempotent and safer to use.
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr> Reported-by: syzbot+d4252148d198410b864f@syzkaller.appspotmail.com Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Latchesar Ionkov <lucho@ionkov.net> --- net/9p/protocol.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/net/9p/protocol.c b/net/9p/protocol.c index 4a1e1dd30b52..ee32bbf12675 100644 --- a/net/9p/protocol.c +++ b/net/9p/protocol.c @@ -46,10 +46,15 @@ p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...); void p9stat_free(struct p9_wstat *stbuf) { kfree(stbuf->name); + stbuf->name = NULL; kfree(stbuf->uid); + stbuf->uid = NULL; kfree(stbuf->gid); + stbuf->gid = NULL; kfree(stbuf->muid); + stbuf->muid = NULL; kfree(stbuf->extension); + stbuf->extension = NULL; } EXPORT_SYMBOL(p9stat_free); -- 2.17.1
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