From: Yuho Choi Date: Mon, 1 Jun 2026 18:32:47 +0000 (-0400) Subject: rpmsg: char: Fix use-after-free on probe error path X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1ff3f528e67d20e2b1483dcaba899dc7832b2e6b;p=thirdparty%2Flinux.git rpmsg: char: Fix use-after-free on probe error path rpmsg_chrdev_probe() stores the newly allocated eptdev in the default endpoint's priv pointer before calling rpmsg_chrdev_eptdev_add(). If rpmsg_chrdev_eptdev_add() then fails, its error path frees eptdev while the default endpoint may still dispatch callbacks with the stale priv pointer. Avoid publishing eptdev through the default endpoint until rpmsg_chrdev_eptdev_add() succeeds. Messages received before the priv pointer is published should be ignored by rpmsg_ept_cb(). Flow-control updates can hit rpmsg_ept_flow_cb() in the same window, so make both callbacks return success when priv is NULL. Fixes: bc69d1066569 ("rpmsg: char: Introduce the "rpmsg-raw" channel") Signed-off-by: Yuho Choi Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20260601183247.1962010-1-dbgh9129@gmail.com Signed-off-by: Mathieu Poirier --- diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index ca9cf8858a5ef..bff5aefee2126 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -104,6 +104,9 @@ static int rpmsg_ept_cb(struct rpmsg_device *rpdev, void *buf, int len, struct rpmsg_eptdev *eptdev = priv; struct sk_buff *skb; + if (!eptdev) + return 0; + skb = alloc_skb(len, GFP_ATOMIC); if (!skb) return -ENOMEM; @@ -124,6 +127,9 @@ static int rpmsg_ept_flow_cb(struct rpmsg_device *rpdev, void *priv, bool enable { struct rpmsg_eptdev *eptdev = priv; + if (!eptdev) + return 0; + eptdev->remote_flow_restricted = enable; eptdev->remote_flow_updated = true; @@ -490,6 +496,7 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) struct rpmsg_channel_info chinfo; struct rpmsg_eptdev *eptdev; struct device *dev = &rpdev->dev; + int ret; memcpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE); chinfo.src = rpdev->src; @@ -502,13 +509,17 @@ static int rpmsg_chrdev_probe(struct rpmsg_device *rpdev) /* Set the default_ept to the rpmsg device endpoint */ eptdev->default_ept = rpdev->ept; + ret = rpmsg_chrdev_eptdev_add(eptdev, chinfo); + + if (ret) + return ret; /* * The rpmsg_ept_cb uses *priv parameter to get its rpmsg_eptdev context. - * Storedit in default_ept *priv field. + * Stored it in default_ept *priv field. */ eptdev->default_ept->priv = eptdev; - return rpmsg_chrdev_eptdev_add(eptdev, chinfo); + return 0; } static void rpmsg_chrdev_remove(struct rpmsg_device *rpdev)