From a7a4866734deac0cb6a1214a1065ffc87f5b2e1d Mon Sep 17 00:00:00 2001 From: Schspa Shi Date: Wed, 29 Jun 2022 10:29:48 +0800 Subject: [PATCH] vfio: Clear the caps->buf to NULL after free [ Upstream commit 6641085e8d7b3f061911517f79a2a15a0a21b97b ] 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 Reviewed-by: Cornelia Huck Link: https://lore.kernel.org/r/20220629022948.55608-1-schspa@gmail.com Signed-off-by: Alex Williamson Signed-off-by: Sasha Levin --- drivers/vfio/vfio.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c index 18fc0916587e..277cd1152dd8 100644 --- a/drivers/vfio/vfio.c +++ b/drivers/vfio/vfio.c @@ -1814,6 +1814,7 @@ 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); }