[PATCH v3 2/3] rpmsg: char: Fix UAF and memory leak in rpmsg_anonymous_eptdev_create()

Dawei Li
2025-11-13T15:39:59Z

Potential UAF and memory leak exsit in exception handling paths for
rpmsg_anonymous_eptdev_create(), fix them.

- If rpmsg_add_eptdev() failes, eptdev is freed in it.
Subsequent call of dev_err(&eptdev->device) triggers a UAF.
- If __rpmsg_eptdev_open() fails, eptdev is supposed to be freed by
put_device().

Fixes: 2410558f5f11 ("rpmsg: char: Implement eptdev based on anonymous inode")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/aPi6gPZE2_ztOjIW@stanley.mountain/
Signed-off-by: Dawei Li <dawei.li@linux.dev>
---
drivers/rpmsg/rpmsg_char.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 1b8297b373f0..0919ad0a19df 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -494,6 +494,7 @@ static int rpmsg_eptdev_add(struct rpmsg_eptdev *eptdev,
if (cdev)
ida_free(&rpmsg_minor_ida, MINOR(dev->devt));
free_eptdev:
+ dev_err(&eptdev->dev, "failed to add %s\n", eptdev->chinfo.name);
kfree(eptdev);

return ret;
@@ -544,7 +545,6 @@ int rpmsg_anonymous_eptdev_create(struct rpmsg_device *rpdev, struct device *par

ret = rpmsg_eptdev_add(eptdev, chinfo, false);
if (ret) {
- dev_err(&eptdev->dev, "failed to add %s\n", eptdev->chinfo.name);
return ret;
}

@@ -560,6 +560,8 @@ int rpmsg_anonymous_eptdev_create(struct rpmsg_device *rpdev, struct device *par

if (!ret)
*pfd = fd;
+ else
+ put_device(&eptdev->dev);

return ret;
}
--
2.25.1