From a26efd1961a18b91ae4cd2e433adbcf865b40fa3 Mon Sep 17 00:00:00 2001
From: Dinghao Liu <dinghao.liu@zju.edu.cn>
Date: Mon, 28 Dec 2020 14:02:05 +0100
Subject: [PATCH] media: em28xx: Fix use-after-free in em28xx_alloc_urbs
Git-commit: a26efd1961a18b91ae4cd2e433adbcf865b40fa3
Patch-mainline: v5.12-rc1
References: git-fixes
When kzalloc() fails, em28xx_uninit_usb_xfer() will free
usb_bufs->buf and set it to NULL. Thus the later access
to usb_bufs->buf[i] will lead to null pointer dereference.
Also the kfree(usb_bufs->buf) after that is redundant.
Fixes: d571b592c6206 ("media: em28xx: don't use coherent buffer for DMA transfers")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/usb/em28xx/em28xx-core.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index e6088b5d1b80..3daa64bb1e1d 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -956,14 +956,10 @@ int em28xx_alloc_urbs(struct em28xx *dev, enum em28xx_mode mode, int xfer_bulk,
usb_bufs->buf[i] = kzalloc(sb_size, GFP_KERNEL);
if (!usb_bufs->buf[i]) {
- em28xx_uninit_usb_xfer(dev, mode);
-
for (i--; i >= 0; i--)
kfree(usb_bufs->buf[i]);
- kfree(usb_bufs->buf);
- usb_bufs->buf = NULL;
-
+ em28xx_uninit_usb_xfer(dev, mode);
return -ENOMEM;
}
--
2.26.2