linux-kernel - Re: [syzbot] Re: [syzbot] [squashfs?] VFS: Close: file count is zero (use-after-free)

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Message-ID: <000000000000e39ee90619f65123@google.com>
Date: Sun, 02 Jun 2024 23:19:46 -0700
From: syzbot <syzbot+b2cfdac9ae5278d4b621@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] Re: [syzbot] [squashfs?] VFS: Close: file count is zero (use-after-free)

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Subject: Re: [syzbot] [squashfs?] VFS: Close: file count is zero (use-after-free)
Author: nightu.pwn@...il.com

please test file uaf in udmabuf_create

#syz test

---
 drivers/dma-buf/udmabuf.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index afa8bfd2a2a9..53035c601e92 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -382,6 +382,7 @@ static long udmabuf_create(struct miscdevice *device,

                kfree(folios);
                fput(memfd);
+               memfd = NULL;
        }

        flags = head->flags & UDMABUF_FLAGS_CLOEXEC ? O_CLOEXEC : 0;
--