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 F2C63352019; Thu, 20 Aug 2026 15:03:54 +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=1787238236; cv=none; b=R5qjD3yyrBoU8u0Mxh9XXMbBkgrNML2XOFVssnxsgCEmYyYir5Uq9GsHene8PssVBeGggmoZFPgpOEgw1TmPMipCxkn5hPfaaGZMuIQIhCTdzDSZl0Ew7BM3RC0NJhP1GB2Tj8TCqvhN8U0wgEvC8I4hOh2Gyzp2mvF4kbqS8yg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787238236; c=relaxed/simple; bh=ZMsn5ITY/pwyl2EuEzzLJcr/Mxf8DIqvsQ4Z637IMdU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=l91E+8+TZoIuf305PHM2y62Igj3wHB+CR5g3y1iF4MKuAtdlUaShp9BlSuDk7YIqcpvXeYaPOagn1ccu7wXpeo6SXJx1LUt/jPOwM467K9MJgyWpNGuGw0GjbO0vDsqv/72qRq/udSfpygfpJtwWJ/V2N02Apq3/RPM8FEysWD8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZxFMGXXZ; 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="ZxFMGXXZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12DCD1F000E9; Thu, 20 Aug 2026 15:03:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787238234; bh=FueaOs8UvyZJjxnBPr1HNUBC1yfHibvkcIKxMLuyAFs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZxFMGXXZ4RLRoCWXw0aPlDYcQgGCyMW4piZKI3LBSNCeZEiXtw0kIU06RK8Dh3/7G 0Jg05pxECSUttevJ3XR466gK4IBbkPHv4tseWY03bO/tMD+WR2kkPHc+U2voZzcXiS AyAcmYRC34SoD4EBphwTqLmj35CoiZl2VpEIuOII= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pavitra Jha , Viacheslav Dubeyko , Ilya Dryomov Subject: [PATCH 7.1 077/228] libceph: fix OOB read in decode_watchers() via missing bounds check Date: Thu, 20 Aug 2026 16:53:39 +0200 Message-ID: <20260820145246.816534900@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145244.450574346@linuxfoundation.org> References: <20260820145244.450574346@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavitra Jha commit 00ead17c7de137a692edee59f2772e6af687e8eb upstream. 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 Signed-off-by: Greg Kroah-Hartman --- net/ceph/osd_client.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -5030,7 +5030,7 @@ static int decode_watchers(void **p, voi 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, voi } return 0; + +bad: + return -EINVAL; } /*