From: Gustavo A. R. Silva <gustavo@embeddedor.com>
Date: Tue, 4 Sep 2018 19:07:49 +0000 (-0500)
Subject: dma-buf/udmabuf: Fix NULL pointer dereference in udmabuf_create
X-Git-Tag: v4.20-rc1~21^2~33^2~12
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=683a0e630cb463d18e9c158496270dc918cf5437;p=linux-2.6-block.git

dma-buf/udmabuf: Fix NULL pointer dereference in udmabuf_create

There is a potential execution path in which pointer memfd is NULL when
passed as argument to fput(), hence there is a NULL pointer dereference
in fput().

Fix this by null checking *memfd* before calling fput().

Addresses-Coverity-ID: 1473174 ("Explicit null dereferenced")
Fixes: fbb0de795078 ("Add udmabuf misc device")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20180904190749.GA9308@embeddedor.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 8e24204526cc..2e8502250afe 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -194,7 +194,8 @@ err_put_pages:
 	while (pgbuf > 0)
 		put_page(ubuf->pages[--pgbuf]);
 err_free_ubuf:
-	fput(memfd);
+	if (memfd)
+		fput(memfd);
 	kfree(ubuf->pages);
 	kfree(ubuf);
 	return ret;