From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 40EF83F8883 for ; Thu, 20 Aug 2026 11:12:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787224339; cv=none; b=Cqq2RlMyoGTHPalBl5S60nmpY2YQ5cMmm1TdA4NLglcHgoy1KMep2OspUSX2htf11VBQudvaWqXoxTTswMvj8B++iWzCuiL/d9Jk8YncPcRSZYfVhcjivlhsC6BYBifMaLCZmcQQICzbG67t/0Y3jTEsVkmKjG3u2VrwyxM/VEQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787224339; c=relaxed/simple; bh=Hmjh00SoVuYqovou0yjEMG8mOvSrQP3eGUyQsOHaM34=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=moTcESn5Fy+xDYvwdiQO3nFC3yMpBS4PuQIbco1upRSGUao7Zn10+NxKvHvM3rVyz3lLvWyL5RXfduwS0vIEeHT2k3mZpcAYyk2PKpftMxNoaKWW0JkjWUcYDOZLqtGglTpV2u9NeZrVnUSRPfgLy/2cT0FAdlZVkPbeH7oSbIM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1bZ0WUXn; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1bZ0WUXn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 366861F000E9; Thu, 20 Aug 2026 11:12:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787224338; bh=fsU4P1330qwPbrQWMCoBhTLH4xXVb4sFbOltCkulp3w=; h=Subject:To:Cc:From:Date; b=1bZ0WUXn9I60efmVLlAnWTTrvKRY0HEqbFy93DeyBEXg0Dvf2lX6C5VkN/CLvq+CD yjW2/mWA7i3GJWXWNtH4i17wm1ihG07sm2fpPHkgpgN2buH0EqxMNvLWqkL1gjv3fW J8jGxFatyNxb4yIruR7MU1V0HRYPXFz6NKUhnWvs= Subject: FAILED: patch "[PATCH] libceph: fix OOB read in decode_watchers() via missing bounds" failed to apply to 5.15-stable tree To: jhapavitra98@gmail.com,Slava.Dubeyko@ibm.com,idryomov@gmail.com Cc: From: Date: Thu, 20 Aug 2026 13:11:57 +0200 Message-ID: <2026082057-aviator-unglazed-0547@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-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 . 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-5.15.y git checkout FETCH_HEAD git cherry-pick -x 00ead17c7de137a692edee59f2772e6af687e8eb # git commit -s git send-email --to '' --in-reply-to '2026082057-aviator-unglazed-0547@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 00ead17c7de137a692edee59f2772e6af687e8eb Mon Sep 17 00:00:00 2001 From: Pavitra Jha Date: Wed, 8 Jul 2026 01:39:41 -0400 Subject: [PATCH] libceph: fix OOB read in decode_watchers() via missing bounds check ceph_start_decoding() validates that struct_len bytes remain in the buffer after the encoding header, but accepts struct_len=0 as valid: ceph_decode_need(p, end, 0, bad) always passes. When a malicious or compromised OSD sends an obj_list_watch_response_t reply with struct_len=0, ceph_start_decoding() returns success with p == end, leaving zero bytes guaranteed for subsequent reads. The immediately following ceph_decode_32(p) in decode_watchers() has no preceding bounds check. With p == end this is a 4-byte read past the validated buffer boundary. The garbage value is then passed directly to kzalloc_objs() as the watcher count. The sibling function decode_watcher() already uses the safe variants (ceph_decode_copy_safe, ceph_decode_64_safe, ceph_decode_skip_32) after its own ceph_start_decoding() call. decode_watchers() is the only site that uses the bare variant, confirming an oversight. Fix by replacing ceph_decode_32(p) with ceph_decode_32_safe(p, end, *num_watchers, bad), consistent with the established pattern. Attacker model: a malicious or compromised OSD in a multi-tenant Ceph deployment (e.g. cloud) can trigger this against any kernel client that calls CEPH_OSD_OP_LIST_WATCHERS, without any further privileges beyond OSD session establishment. [ idryomov: trim changelog ] Cc: stable@vger.kernel.org Fixes: a4ed38d7a180 ("libceph: support for CEPH_OSD_OP_LIST_WATCHERS") Signed-off-by: Pavitra Jha Reviewed-by: Viacheslav Dubeyko Signed-off-by: Ilya Dryomov diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c index 2ff00070c181..28d76c2f6b3e 100644 --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -5030,7 +5030,7 @@ static int decode_watchers(void **p, void *end, if (ret) return ret; - *num_watchers = ceph_decode_32(p); + ceph_decode_32_safe(p, end, *num_watchers, bad); *watchers = kzalloc_objs(**watchers, *num_watchers, GFP_NOIO); if (!*watchers) return -ENOMEM; @@ -5044,6 +5044,9 @@ static int decode_watchers(void **p, void *end, } return 0; + +bad: + return -EINVAL; } /*