From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.128.52 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794413922; b=aM64dEn10kup/+pPP5k3CFEyhZALQJajI1zCLjZ3S7Y8C0OXWAeUskKlZIvQ/3zaXkS8 dC10K/DdFQ/tZFkKLjBvuy948Lb+faBOd4lcPT1U8GXv6qmxwiuvuwYNbiF11CUB7pExi Ub0aQEfC8/FJuqN24ht1SdrZx5p8+fx2RBLsnlUtX0pVUsCKPVwh/A7Ur1JU3sd1uj0jv 41i5TXTAeCVV9W/nPd4xQo58aSi59qObQ8aC4TyFAqi6K5naqEFwwbgLa469Q5xBKEHil BHhQXLRH5OrTBmt1qSFEc9ypVnt59uVXoNuw3HTdcT+/lBoz6u6L8j/rfSmQ4cQ8P2Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794413922; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-ID:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=izt2/XobLLqiqgA/+J+pbNOAtloWX7VwrLq7qFAm7og=; b=nPW/cPqlUQYzBXt6w9D3zZAz8Lu7AUVHjFPAEXWVxwddsuIT6PZZRnFXSqlizbo6EOxm d+mERWQRz5vnOSyYv4hb6nZNFVg6yPQ+JaRU13jUuTPrXJK2uNSQmxIEz+UHK3wUrpoc8 LvgxwiaojdBqkrBY65QCvdCiop9h2IooT33lLaPqb+isW9l8N9y8p4jiEsGKp6m4D8TjN a6Yll88mYOPbmh6NqONVi0FwmEekwQDZ12uDi24C4nly/cunytSIk0vhZrwBFYQLIrUYe MvpSRA9M88/rxb6FbP4NtSQbZeWshzJ0fGZKiqgljkraOWPfMiqu5oq/wogbWWgcc7Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=ionos.com; spf=pass smtp.mailfrom=ionos.com; dkim=pass header.d=ionos.com header.i=@ionos.com header.a=rsa-sha256 header.s=google header.b=h6ew7d3v; arc=none smtp.remote-ip=209.85.128.52 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A5A0460A2638 for ; Wed, 11 Nov 2026 16:18:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org A5A0460A2638 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=ionos.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ionos.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ionos.com header.i=@ionos.com header.a=rsa-sha256 header.s=google header.b=h6ew7d3v Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-4afe2d546f9so41822575e9.3 for ; Wed, 11 Nov 2026 08:18:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ionos.com; s=google; t=1794413920; x=1795018720; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=izt2/XobLLqiqgA/+J+pbNOAtloWX7VwrLq7qFAm7og=; b=h6ew7d3v9vf+Kt4CULQmOkrk+4e7JAubTLtfJ7E/tSjtsBGHL9SF6ngarbtIfGRi7h rbsDjhgtddpXtFjcd+ySROzj/rbNWdonvsfTizLLb6dxcLjM9g8F5ouUxNL4tqzr2QYs GxbdA1+axsxLjLiS8/RT7IhwkPVQR9S1LKgbiaIeE4pchX7GWlYu/XGnhl6ZZ0BPf0EI yb+6CIhhZuspDWtoCpycFnQ8v2aYnTIKQvzuWY58Sn9avpw87EMnDUUXYRauoRgQEdIh jNL93vujq4WplSxed1q7pIkgDzIkQvjIvCjEhF062CPfzj/rwNwiSc1hA45Q22s7oWYI a5QQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794413920; x=1795018720; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=izt2/XobLLqiqgA/+J+pbNOAtloWX7VwrLq7qFAm7og=; b=dDapCOiftHvla1fmSgcn9EKt0TdLw1Grw+w0bDBpfZVOYEA1yjMfAoR7zKRVXBC/PE gerWcA3S6DRgMscxWuhfPZumEU1KCQoy7vACzZjpuOxQZ3ETAl3TZ8wUKsvrgTVFiB14 0JHpp9GMRZsgxuLYHzNAnosA/89Sb78ZQ85ZJZUFSnbLUlPv/hXGL14fRNZEobIVciMV XkvJ74d+QARwxyjrBp8opkitFY+328Go0ry0w8mICWig5Ren4kHAXOPQG6mrbLArm+Fy USpf7c8QaJW7hDaeeWJdISl8EyzlGiGQjElvbBhhWG5PcyonXZ9Qt7xUx2NuAZL1yr5p JRwg== X-Forwarded-Encrypted: i=1; AL+hErEi8DhqE/3ycQmyVFY2bIKqk5xX77cV0+JkmszAjIhsfMcTMpWqFCSRMPR2EC1vLVh6gS27AwY=@vger.kernel.org X-Gm-Message-State: APuU4Z9usio23EQ5A4iv+F36hGY5cEZzoObOfuH5UqRnqFTxjKAvKaxU 0SW6w5Kty+JvEo/F8KMuArqKUw6RJNGxKJIHxGGuzr3z8FaDjujAQXKbJdaqkRdE8dw= X-Gm-Gg: AYBFou0TIQlqlLEPJwE4q/6sPI07ZWV7C4pm2zSlbJmZgaR9CxlG/+wZGrn0M5YcWIs 4MgXJ4OQl0ol4vAR1RT2YyXYts/cm4upE6cW2qW6hCbMOebD3FuEBZwteOC13G4vQ1N2U/jb7rO 3DZ4zIvSfGoEWtNGtkz07BAA2Emjqzyb7AeeZ/ElJVffDUmffqa7Jzm/YssJb4eEYH4TqQNr7aI pJf6BgSi1KWGs+GdxlQt+ua6wAamThXNVVLEKJeIfQlMy6GEFPmk9A2QeMVJUtydiovRwHN8XPz N2JTZhp+2P5lKgwPZk1cNk+VZqg+MsZUtH2MwtXz5slQwknkQLEgHbToahJ1WvOKZ9oMhwHdBFO XphGJUZHU3CTF8TqKDLyb8Y3W/bLSbt5taG3CEiZgIVGvsTS1qlb2QovXSl/pkALM5MrCFkIjFe OZS1tLa7FILMRZd1lT1xYVn59ZbCZPPPZ8+pATftjnzRFCXNXGB3iTxKpYlklVgFYkrw2xNff7V TWEiwLiK9YJMekknt6L7e/S+8usbkIO6cPk1tDGEWEIcSITKaErVrZRvsgDysBxFP/aktx0qk2q ZG+LBmuftz26vpwtAjKQTH9PyMGiDui2jRR/K/1eZskJ7xEulf92D7MspdXeCdWkRzHynwFwcQC n1dLvgbSjlyOnAaIh57u3TB8SNdGUbg== X-Received: by 2002:a05:6000:268a:b0:48d:ee35:b3fe with SMTP id ffacd0b85a97d-499c57838f3mr4997398f8f.8.1794413919771; Wed, 11 Nov 2026 08:18:39 -0800 (PST) Received: from raven.intern.cm-ag (p200300dc6f4cbe00023064fffe740809.dip0.t-ipconnect.de. [2003:dc:6f4c:be00:230:64ff:fe74:809]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4983600bd6esm12209506f8f.28.2026.11.11.08.18.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 11 Nov 2026 08:18:39 -0800 (PST) From: Max Kellermann To: xiubli@redhat.com, idryomov@gmail.com, amarkuze@redhat.com, ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Max Kellermann , stable@vger.kernel.org Subject: [PATCH 5/9] ceph: fix mdsmap use-after-free in mds_peer_reset() Date: Wed, 11 Nov 2026 17:18:26 +0100 Message-ID: <20261111161830.1336485-6-max.kellermann@ionos.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261111161830.1336485-1-max.kellermann@ionos.com> References: <20261111161830.1336485-1-max.kellermann@ionos.com> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit mds_peer_reset() reads the MDS state from mdsc->mdsmap without holding mdsc->mutex, but ceph_mdsc_handle_mdsmap() replaces the mdsmap and frees the old one under that mutex. A peer reset often coincides with an MDS failover, which is exactly when a new mdsmap arrives, so this can read freed memory. Read the state while holding mdsc->mutex. The messenger drops con->mutex before calling ->peer_reset(), so no lock is held here. Fixes: cbcb358b744b ("ceph: skip reconnecting if MDS is not ready") Cc: stable@vger.kernel.org Signed-off-by: Max Kellermann --- fs/ceph/mds_client.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index a43ce23d48f4..aa4406fd65b9 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -7300,13 +7300,19 @@ static void mds_peer_reset(struct ceph_connection *con) { struct ceph_mds_session *s = con->private; struct ceph_mds_client *mdsc = s->s_mdsc; + int mds_state; int rc; pr_warn_client(mdsc->fsc->client, "mds%d closed our session\n", s->s_mds); + /* ceph_mdsc_handle_mdsmap() replaces and frees the mdsmap */ + mutex_lock(&mdsc->mutex); + mds_state = ceph_mdsmap_get_state(mdsc->mdsmap, s->s_mds); + mutex_unlock(&mdsc->mutex); + if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_FENCE_IO || - ceph_mdsmap_get_state(mdsc->mdsmap, s->s_mds) < CEPH_MDS_STATE_RECONNECT) + mds_state < CEPH_MDS_STATE_RECONNECT) return; /* -- 2.53.0