From: Steve Cohen <cohens@codeaurora.org>
To: dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org,
linux-arm-msm@vger.kernel.org
Cc: adelva@google.com, seanpaul@chromium.org, pdhaval@codeaurora.org,
Steve Cohen <cohens@codeaurora.org>
Subject: [PATCH] drm: hold gem reference until object is no longer accessed
Date: Fri, 10 Jul 2020 18:40:26 -0400 [thread overview]
Message-ID: <1594420826-4897-1-git-send-email-cohens@codeaurora.org> (raw)
BUG: KASAN: use-after-free in drm_gem_open_ioctl
There is potential for use-after-free here if the GEM object
handle is closed between the idr lookup and retrieving the size
from the object since a local reference is not being held at that
point. Hold the local reference while the object can still be
accessed to resolve this.
Signed-off-by: Steve Cohen <cohens@codeaurora.org>
---
drivers/gpu/drm/drm_gem.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 7bf628e..4b2891c 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -898,14 +898,15 @@ drm_gem_open_ioctl(struct drm_device *dev, void *data,
/* drm_gem_handle_create_tail unlocks dev->object_name_lock. */
ret = drm_gem_handle_create_tail(file_priv, obj, &handle);
- drm_gem_object_put_unlocked(obj);
if (ret)
- return ret;
+ goto out;
args->handle = handle;
args->size = obj->size;
- return 0;
+out:
+ drm_gem_object_put_unlocked(obj);
+ return ret;
}
/**
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel
next reply other threads:[~2020-07-14 7:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 22:40 Steve Cohen [this message]
2020-07-16 20:29 ` [PATCH] drm: hold gem reference until object is no longer accessed Sam Ravnborg
2020-07-19 13:39 ` Sam Ravnborg
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1594420826-4897-1-git-send-email-cohens@codeaurora.org \
--to=cohens@codeaurora.org \
--cc=adelva@google.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=freedreno@lists.freedesktop.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=pdhaval@codeaurora.org \
--cc=seanpaul@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).