From d3c32939fa0e3ee9b883b9a0fd1972c5c444e3d0 Mon Sep 17 00:00:00 2001 From: Douya Le Date: Sun, 7 Jun 2026 17:35:49 +0800 Subject: [PATCH] libceph: bound get_version reply decode to front len handle_get_version_reply() uses msg->front_alloc_len as the decode boundary for MON_GET_VERSION_REPLY. That is the size of the reused reply buffer, not the number of bytes actually received. A truncated reply can therefore pass ceph_decode_need() and decode the second u64 from stale tail bytes left in the buffer by an earlier message, causing an uninitialized memory read. Use msg->front.iov_len as the receive-side decode boundary, matching other libceph reply handlers and limiting decoding to the bytes that were actually read from the wire. Cc: stable@vger.kernel.org Fixes: 513a8243d67f ("libceph: mon_get_version request infrastructure") Reported-by: Yuan Tan Reported-by: Zhengchuan Liang Reported-by: Xin Liu Assisted-by: Codex:GPT-5.4 Signed-off-by: Douya Le Signed-off-by: Ren Wei Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov --- net/ceph/mon_client.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c index 24acdd580e79..c56457378d00 100644 --- a/net/ceph/mon_client.c +++ b/net/ceph/mon_client.c @@ -821,7 +821,7 @@ static void handle_get_version_reply(struct ceph_mon_client *monc, struct ceph_mon_generic_request *req; u64 tid = le64_to_cpu(msg->hdr.tid); void *p = msg->front.iov_base; - void *end = p + msg->front_alloc_len; + void *const end = p + msg->front.iov_len; u64 handle; dout("%s msg %p tid %llu\n", __func__, msg, tid);