From: Schspa Shi <schspa@gmail.com>
Date: Wed, 29 Jun 2022 02:29:48 +0000 (+0800)
Subject: vfio: Clear the caps->buf to NULL after free
X-Git-Tag: baikal/mips/sdk6.1~5111^2~19^5
X-Git-Url: https://git.baikalelectronics.ru/sdk/?a=commitdiff_plain;h=8c359d0ff88a09f802b77f60d22797a04ef72afa;p=kernel.git

vfio: Clear the caps->buf to NULL after free

On buffer resize failure, vfio_info_cap_add() will free the buffer,
report zero for the size, and return -ENOMEM.  As additional
hardening, also clear the buffer pointer to prevent any chance of a
double free.

Signed-off-by: Schspa Shi <schspa@gmail.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Link: https://lore.kernel.org/r/20220629022948.55608-1-schspa@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 61e71c1154be6..a0fb93866f611 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1812,6 +1812,7 @@ struct vfio_info_cap_header *vfio_info_cap_add(struct vfio_info_cap *caps,
 	buf = krealloc(caps->buf, caps->size + size, GFP_KERNEL);
 	if (!buf) {
 		kfree(caps->buf);
+		caps->buf = NULL;
 		caps->size = 0;
 		return ERR_PTR(-ENOMEM);
 	}