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[5.4,158/475] udmabuf: validate ubuf->pagecount

Message ID 20220414110859.562512974@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman April 14, 2022, 1:09 p.m. UTC 
From: Pavel Skripkin <paskripkin@gmail.com>

[ Upstream commit 2b6dd600dd72573c23ea180b5b0b2f1813405882 ]

Syzbot has reported GPF in sg_alloc_append_table_from_pages(). The
problem was in ubuf->pages == ZERO_PTR.

ubuf->pagecount is calculated from arguments passed from user-space. If
user creates udmabuf with list.size == 0 then ubuf->pagecount will be
also equal to zero; it causes kmalloc_array() to return ZERO_PTR.

Fix it by validating ubuf->pagecount before passing it to
kmalloc_array().

Fixes: fbb0de795078 ("Add udmabuf misc device")
Reported-and-tested-by: syzbot+2c56b725ec547fa9cb29@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20211230142649.23022-1-paskripkin@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/dma-buf/udmabuf.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c
index 9635897458a0..e553c6a937f6 100644
--- a/drivers/dma-buf/udmabuf.c
+++ b/drivers/dma-buf/udmabuf.c
@@ -145,6 +145,10 @@  static long udmabuf_create(const struct udmabuf_create_list *head,
 		if (ubuf->pagecount > pglimit)
 			goto err;
 	}
+
+	if (!ubuf->pagecount)
+		goto err;
+
 	ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages),
 				    GFP_KERNEL);
 	if (!ubuf->pages) {