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From:   Jiebin Sun <jiebin.sun@intel.com>
To:     akpm@linux-foundation.org, vasily.averin@linux.dev,
        shakeelb@google.com, dennis@kernel.org, tj@kernel.org,
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Cc:     tim.c.chen@intel.com, feng.tang@intel.com, ying.huang@intel.com,
        tianyou.li@intel.com, wangyang.guo@intel.com, jiebin.sun@intel.com,
        Manfred Spraul <manfred@colorfullif.com>,
        Tim Chen <tim.c.chen@linux.intel.com>
Subject: [PATCH] ipc/msg: avoid negative value by overflow in msginfo
Date:   Tue, 20 Sep 2022 23:08:09 +0800
Message-Id: <20220920150809.4014944-1-jiebin.sun@intel.com>
In-Reply-To: <8d74a7d4-b80f-2a0f-ee95-243bdbd51ccd@colorfullife.com>
References: <8d74a7d4-b80f-2a0f-ee95-243bdbd51ccd@colorfullife.com>
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The 32-bit value in msginfo struct could be negative if we get it
from signed 64-bit. Clamping it to INT_MAX helps to avoid the
negative value by overflow.

Signed-off-by: Jiebin Sun <jiebin.sun@intel.com>
Reviewed-by: Manfred Spraul <manfred@colorfullif.com>
Reviewed-by: Tim Chen <tim.c.chen@linux.intel.com>
---
 ipc/msg.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ipc/msg.c b/ipc/msg.c
index f2bb4c193ecf..65f437e28c9b 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -501,8 +501,8 @@ static int msgctl_info(struct ipc_namespace *ns, int msqid,
 	max_idx = ipc_get_maxidx(&msg_ids(ns));
 	up_read(&msg_ids(ns).rwsem);
 	if (cmd == MSG_INFO) {
-		msginfo->msgmap = percpu_counter_sum(&ns->percpu_msg_hdrs);
-		msginfo->msgtql = percpu_counter_sum(&ns->percpu_msg_bytes);
+		msginfo->msgmap = min(percpu_counter_sum(&ns->percpu_msg_hdrs), INT_MAX);
+		msginfo->msgtql = min(percpu_counter_sum(&ns->percpu_msg_bytes), INT_MAX);
 	} else {
 		msginfo->msgmap = MSGMAP;
 		msginfo->msgpool = MSGPOOL;
-- 
2.31.1