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 3CBC847D949; Tue, 25 Aug 2026 14:00:47 +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=1787666448; cv=none; b=gITsg9nai3cD2LWu4LfplMb7qGMU67cvfnDRdmej+30jt2ks7Wg+qB8pcpBkpq4VRKGplb1W8HRc/Epql+eJTY3dd8wrUyinGRwBConlWMvJqrmbVZk7TzJqO7fjBnWEFXA9gbPe1KKOnHS0r7m7C9pOKM8t2cOg74xiS7cDeM4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787666448; c=relaxed/simple; bh=rgEOUiGLakZuNyvlLi+u6iOhzdaUAft4aqYmBmrxy04=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PfOlsbET2jUpCoadOhjMqMAsNNGozXVhxZSle2T9YtUgk9LA0hIVjGn3gTLhkCIFwhrokRh5Xeo1GxiLd/MGBhJSZgQSIsg1tAqLJ2BHsWi+VoIRjrxtS7U8ZKE5/TIQZGlkfs8VZRdU2j+TTBULZ8hKOMVPMH6/35Rn6nx+Mmo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=L6bp5ROO; 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="L6bp5ROO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A8481F00A3A; Tue, 25 Aug 2026 14:00:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787666446; bh=rQ6wuTq1yFBKUA2YdA8yK0qYs3nXYynOX/2jCZZSdMM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=L6bp5ROOoxoueYDdXw9wTWqhMb4UBS5G65fDzyF9PBFqrzjgMboX+kO0AgbF+EDyn ZpGr1QtJ/uwRbMjITBReVoDhvNZwez6CyxWyPRer9jwIiOmrRArRcMYSmXeGuWU0kU P4zkOg++lrbLXLUXWb5ColdPAxC83APe5e/bBEy0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pavitra Jha , Viacheslav Dubeyko , Ilya Dryomov , Sasha Levin Subject: [PATCH 5.10 45/57] libceph: fix OOB read in decode_watchers() via missing bounds check Date: Tue, 25 Aug 2026 15:27:07 +0200 Message-ID: <20260825132543.099548855@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260825132541.342390421@linuxfoundation.org> References: <20260825132541.342390421@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 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pavitra Jha [ Upstream commit 00ead17c7de137a692edee59f2772e6af687e8eb ] 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: Sasha Levin 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 @@ -4993,7 +4993,7 @@ 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 = kcalloc(*num_watchers, sizeof(**watchers), GFP_NOIO); if (!*watchers) return -ENOMEM; @@ -5007,6 +5007,9 @@ static int decode_watchers(void **p, voi } return 0; + +bad: + return -EINVAL; } /*