FAILED: patch "[PATCH] net: qrtr: ns: Limit the total number of nodes" failed to apply to 6.12-stable tree

FAILED: patch "[PATCH] net: qrtr: ns: Limit the total number of nodes" failed to apply to 6.12-stable tree

[gregkh]

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 27d5e84e810b0849d08b9aec68e48570461ce313
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026050151-baked-tipper-7f00@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 27d5e84e810b0849d08b9aec68e48570461ce313 Mon Sep 17 00:00:00 2001
From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Date: Thu, 9 Apr 2026 23:04:15 +0530
Subject: [PATCH] net: qrtr: ns: Limit the total number of nodes

Currently, the nameserver doesn't limit the number of nodes it handles.
This can be an attack vector if a malicious client starts registering
random nodes, leading to memory exhaustion.

Hence, limit the maximum number of nodes to 64. Note that, limit of 64 is
chosen based on the current platform requirements. If requirement changes
in the future, this limit can be increased.

Cc: stable@vger.kernel.org
Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Link: https://patch.msgid.link/20260409-qrtr-fix-v3-4-00a8a5ff2b51@oss.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
index 1b9a90240a68..c0418764470b 100644
--- a/net/qrtr/ns.c
+++ b/net/qrtr/ns.c
@@ -71,12 +71,16 @@ struct qrtr_node {
 	u32 server_count;
 };
 
-/* Max server, lookup limits are chosen based on the current platform requirements.
- * If the requirement changes in the future, these values can be increased.
+/* Max nodes, server, lookup limits are chosen based on the current platform
+ * requirements. If the requirement changes in the future, these values can be
+ * increased.
  */
+#define QRTR_NS_MAX_NODES   64
 #define QRTR_NS_MAX_SERVERS 256
 #define QRTR_NS_MAX_LOOKUPS 64
 
+static u8 node_count;
+
 static struct qrtr_node *node_get(unsigned int node_id)
 {
 	struct qrtr_node *node;
@@ -85,6 +89,11 @@ static struct qrtr_node *node_get(unsigned int node_id)
 	if (node)
 		return node;
 
+	if (node_count >= QRTR_NS_MAX_NODES) {
+		pr_err_ratelimited("QRTR clients exceed max node limit!\n");
+		return NULL;
+	}
+
 	/* If node didn't exist, allocate and insert it to the tree */
 	node = kzalloc_obj(*node);
 	if (!node)
@@ -98,6 +107,8 @@ static struct qrtr_node *node_get(unsigned int node_id)
 		return NULL;
 	}
 
+	node_count++;
+
 	return node;
 }
 
@@ -404,6 +415,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)
 delete_node:
 	xa_erase(&nodes, from->sq_node);
 	kfree(node);
+	node_count--;
 
 	return ret;
 }

[PATCH 6.12.y 1/2] net: qrtr: ns: Free the node during ctrl_cmd_bye()

[Sasha Levin]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

[ Upstream commit 68efba36446a7774ea5b971257ade049272a07ac ]

A node sends the BYE packet when it is about to go down. So the nameserver
should advertise the removal of the node to all remote and local observers
and free the node finally. But currently, the nameserver doesn't free the
node memory even after processing the BYE packet. This causes the node
memory to leak.

Hence, remove the node from Xarray list and free the node memory during
both success and failure case of ctrl_cmd_bye().

Cc: stable@vger.kernel.org
Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Link: https://patch.msgid.link/20260409-qrtr-fix-v3-3-00a8a5ff2b51@oss.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 27d5e84e810b ("net: qrtr: ns: Limit the total number of nodes")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/qrtr/ns.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
index 3de9350cbf307..e1f27464279cf 100644
--- a/net/qrtr/ns.c
+++ b/net/qrtr/ns.c
@@ -341,7 +341,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)
 	struct qrtr_node *node;
 	unsigned long index;
 	struct kvec iv;
-	int ret;
+	int ret = 0;
 
 	iv.iov_base = &pkt;
 	iv.iov_len = sizeof(pkt);
@@ -356,8 +356,10 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)
 
 	/* Advertise the removal of this client to all local servers */
 	local_node = node_get(qrtr_ns.local_node);
-	if (!local_node)
-		return 0;
+	if (!local_node) {
+		ret = 0;
+		goto delete_node;
+	}
 
 	memset(&pkt, 0, sizeof(pkt));
 	pkt.cmd = cpu_to_le32(QRTR_TYPE_BYE);
@@ -374,10 +376,18 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)
 		ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));
 		if (ret < 0 && ret != -ENODEV) {
 			pr_err("failed to send bye cmd\n");
-			return ret;
+			goto delete_node;
 		}
 	}
-	return 0;
+
+	/* Ignore -ENODEV */
+	ret = 0;
+
+delete_node:
+	xa_erase(&nodes, from->sq_node);
+	kfree(node);
+
+	return ret;
 }
 
 static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,
-- 
2.53.0

[PATCH 6.12.y 2/2] net: qrtr: ns: Limit the total number of nodes

[Sasha Levin]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

[ Upstream commit 27d5e84e810b0849d08b9aec68e48570461ce313 ]

Currently, the nameserver doesn't limit the number of nodes it handles.
This can be an attack vector if a malicious client starts registering
random nodes, leading to memory exhaustion.

Hence, limit the maximum number of nodes to 64. Note that, limit of 64 is
chosen based on the current platform requirements. If requirement changes
in the future, this limit can be increased.

Cc: stable@vger.kernel.org
Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Link: https://patch.msgid.link/20260409-qrtr-fix-v3-4-00a8a5ff2b51@oss.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ dropped comment/define changes for missing QRTR_NS_MAX_SERVERS/LOOKUPS prereqs and kept plain kzalloc instead of kzalloc_obj ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/qrtr/ns.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
index e1f27464279cf..adb6a4ba093db 100644
--- a/net/qrtr/ns.c
+++ b/net/qrtr/ns.c
@@ -69,6 +69,13 @@ struct qrtr_node {
 	struct xarray servers;
 };
 
+/* Max nodes limit is chosen based on the current platform requirements.
+ * If the requirement changes in the future, this value can be increased.
+ */
+#define QRTR_NS_MAX_NODES   64
+
+static u8 node_count;
+
 static struct qrtr_node *node_get(unsigned int node_id)
 {
 	struct qrtr_node *node;
@@ -77,6 +84,11 @@ static struct qrtr_node *node_get(unsigned int node_id)
 	if (node)
 		return node;
 
+	if (node_count >= QRTR_NS_MAX_NODES) {
+		pr_err_ratelimited("QRTR clients exceed max node limit!\n");
+		return NULL;
+	}
+
 	/* If node didn't exist, allocate and insert it to the tree */
 	node = kzalloc(sizeof(*node), GFP_KERNEL);
 	if (!node)
@@ -90,6 +102,8 @@ static struct qrtr_node *node_get(unsigned int node_id)
 		return NULL;
 	}
 
+	node_count++;
+
 	return node;
 }
 
@@ -386,6 +400,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from)
 delete_node:
 	xa_erase(&nodes, from->sq_node);
 	kfree(node);
+	node_count--;
 
 	return ret;
 }
-- 
2.53.0