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FAILED: patch "[PATCH] net: qrtr: ns: Limit the maximum number of lookups" failed to apply to 6.18-stable tree

PATCH New [email protected] 2 participants 2 messages May 1 – May 3

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Networking Stable branch Qualcomm IPC router (QRTR) driver
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author maintainer
#0 lore raw

The patch below does not apply to the 6.18-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 <[email protected]>.

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-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 5640227d9a21c6a8be249a10677b832e7f40dc55
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026050116-sibling-trace-05b5@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 5640227d9a21c6a8be249a10677b832e7f40dc55 Mon Sep 17 00:00:00 2001
From: Manivannan Sadhasivam <[email protected]>
Date: Thu, 9 Apr 2026 23:04:13 +0530
Subject: [PATCH] net: qrtr: ns: Limit the maximum number of lookups

Current code does no bound checking on the number of lookups a client can perform. Though the code restricts the lookups to local clients, there is still a possibility of a malicious local client sending a flood of NEW_LOOKUP messages over the same socket.

Fix this issue by limiting the maximum number of lookups to 64 globally. Since the nameserver allows only atmost one local observer, this global lookup count will ensure that the lookups stay within the limit.

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 [email protected]
Fixes 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by Manivannan Sadhasivam <[email protected]>
Link https://patch.msgid.link/[email protected] open here
Signed-off-by Jakub Kicinski <[email protected]>
net/qrtr/ns.c +12 -2
index 63cb5861d87a..5b08d4d4840a 100644
@@ -22,6 +22,7 @@ static struct {
 	struct socket *sock;
 	struct sockaddr_qrtr bcast_sq;
 	struct list_head lookups;
+	u32 lookup_count;
 	struct workqueue_struct *workqueue;
 	struct work_struct work;
 	int local_node;

@@ -70,10 +71,11 @@ struct qrtr_node {
 	u32 server_count;
 };
 
-/* Max server limit is chosen based on the current platform requirements. If the
- * requirement changes in the future, this value can be increased.
+/* Max 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_SERVERS 256
+#define QRTR_NS_MAX_LOOKUPS 64
 
 static struct qrtr_node *node_get(unsigned int node_id)
 {

@@ -433,6 +435,7 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,
 
 		list_del(&lookup->li);
 		kfree(lookup);
+		qrtr_ns.lookup_count--;
 	}
 
 	/* Remove the server belonging to this port but don't broadcast

@@ -550,6 +553,11 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,
 	if (from->sq_node != qrtr_ns.local_node)
 		return -EINVAL;
 
+	if (qrtr_ns.lookup_count >= QRTR_NS_MAX_LOOKUPS) {
+		pr_err_ratelimited("QRTR client node exceeds max lookup limit!\n");
+		return -ENOSPC;
+	}
+
 	lookup = kzalloc_obj(*lookup);
 	if (!lookup)
 		return -ENOMEM;

@@ -558,6 +566,7 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,
 	lookup->service = service;
 	lookup->instance = instance;
 	list_add_tail(&lookup->li, &qrtr_ns.lookups);
+	qrtr_ns.lookup_count++;
 
 	memset(&filter, 0, sizeof(filter));
 	filter.service = service;

@@ -598,6 +607,7 @@ static void ctrl_cmd_del_lookup(struct sockaddr_qrtr *from,
 
 		list_del(&lookup->li);
 		kfree(lookup);
+		qrtr_ns.lookup_count--;
 	}
 }
maintainer
#1 lore raw

PATCH 1/1 net: qrtr: ns: Limit the maximum number of lookups

From: Manivannan Sadhasivam <[email protected]>

[ Upstream commit 5640227d9a21c6a8be249a10677b832e7f40dc55 ]

Current code does no bound checking on the number of lookups a client can perform. Though the code restricts the lookups to local clients, there is still a possibility of a malicious local client sending a flood of NEW_LOOKUP messages over the same socket.

Fix this issue by limiting the maximum number of lookups to 64 globally. Since the nameserver allows only atmost one local observer, this global lookup count will ensure that the lookups stay within the limit.

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 [email protected]
Fixes 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by Manivannan Sadhasivam <[email protected]>
Link https://patch.msgid.link/[email protected] open here
Signed-off-by Jakub Kicinski <[email protected]>
[ adapted comment block to only mention QRTR_NS_MAX_LOOKUPS and kept kzalloc() instead of kzalloc_obj() due to missing prerequisite commits ]
Signed-off-by Sasha Levin <[email protected]>
---
 net/qrtr/ns.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
net/qrtr/ns.c +14 -0
index 3de9350cbf307..2a039153136cf 100644
@@ -22,6 +22,7 @@ static struct {
 	struct socket *sock;
 	struct sockaddr_qrtr bcast_sq;
 	struct list_head lookups;
+	u32 lookup_count;
 	struct workqueue_struct *workqueue;
 	struct work_struct work;
 	int local_node;

@@ -69,6 +70,11 @@ struct qrtr_node {
 	struct xarray servers;
 };
 
+/* Max lookup 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_LOOKUPS 64
+
 static struct qrtr_node *node_get(unsigned int node_id)
 {
 	struct qrtr_node *node;

@@ -417,6 +423,7 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,
 
 		list_del(&lookup->li);
 		kfree(lookup);
+		qrtr_ns.lookup_count--;
 	}
 
 	/* Remove the server belonging to this port but don't broadcast

@@ -534,6 +541,11 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,
 	if (from->sq_node != qrtr_ns.local_node)
 		return -EINVAL;
 
+	if (qrtr_ns.lookup_count >= QRTR_NS_MAX_LOOKUPS) {
+		pr_err_ratelimited("QRTR client node exceeds max lookup limit!\n");
+		return -ENOSPC;
+	}
+
 	lookup = kzalloc(sizeof(*lookup), GFP_KERNEL);
 	if (!lookup)
 		return -ENOMEM;

@@ -542,6 +554,7 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,
 	lookup->service = service;
 	lookup->instance = instance;
 	list_add_tail(&lookup->li, &qrtr_ns.lookups);
+	qrtr_ns.lookup_count++;
 
 	memset(&filter, 0, sizeof(filter));
 	filter.service = service;

@@ -582,6 +595,7 @@ static void ctrl_cmd_del_lookup(struct sockaddr_qrtr *from,
 
 		list_del(&lookup->li);
 		kfree(lookup);
+		qrtr_ns.lookup_count--;
 	}
 }
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