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9p: clear dangling pointers in p9stat_free
authorDominique Martinet <dominique.martinet@cea.fr>
Mon, 27 Aug 2018 22:32:35 +0000 (07:32 +0900)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 21 Nov 2018 08:19:12 +0000 (09:19 +0100)
commit36c99a16366115cb339148ff8f6d45383d85e080
tree984f5610252e7e796c387e4074210467a65474e5
parent7e0a5da540fbc4cbcc3edef4b5c99387bb513092
9p: clear dangling pointers in p9stat_free

[ Upstream commit 62e3941776fea8678bb8120607039410b1b61a65 ]

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.

Link: http://lkml.kernel.org/r/1535410108-20650-2-git-send-email-asmadeus@codewreck.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Reported-by: syzbot+d4252148d198410b864f@syzkaller.appspotmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/9p/protocol.c