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 2149B380FC7; Thu, 20 Aug 2026 15:17:26 +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=1787239047; cv=none; b=rpJe1JTZYYQod5iXoAlaDUxCf1kw8CFRN1nQjGxvZRnyiNgQ9KZM7cl4j3miLnKFJiUurujbvf7hHwMONCIOPckYm0PzZK2NwEPg7igkBZDxnU0wOiMkvL3wADCa7xjA/5A1Ef35B4dYzM/0+sMmnPmTpwGbrBraMqppYm4DGqg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787239047; c=relaxed/simple; bh=jtEejb2USSJw9r4F2mwcTnsTw9GcFYAphP4cBtIzGG4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FCblqFtQrz2PUmrB4gAJbRGHy1tG7RKK+fMKQoSmbUgjUb4YeiVCkFxygB1zaHAgW/ese1cp6aJpZ2c/DkGBLX7XwuAWEpxBJgR2F04mFdKjyPOJ4dybNYtmO/wj/ZM1rjvCJLfro1xdGW7sV4dpR9oVx83IE2X0hEdKvkgZr9c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=CsBs/1B5; 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="CsBs/1B5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7165C1F000E9; Thu, 20 Aug 2026 15:17:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787239046; bh=6YlrixAEvMCbK/7uGXe8eCxTixRTWpag25x/F9U7iX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=CsBs/1B5l0yQkTppYcm1HXbekNPxwnU7E55a3SNkzdgrCEBABFNSJ1uTzI26j1eh+ vbRRYvkxZwNOxxLmoW9HRQZaceMnh2QCLi3QFLrOvoX2w+veFjLzeGYghwEDBWPVHJ b+3kAs8xPa8nwpEfjaJyEDAF8RTwZE5QnyGLtv24= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Xiang Mei , Alex Markuze , Ilya Dryomov , Sasha Levin Subject: [PATCH 6.18 132/217] libceph: bound pg_{temp,upmap,upmap_items} length to CEPH_PG_MAX_SIZE Date: Thu, 20 Aug 2026 16:55:00 +0200 Message-ID: <20260820145241.717819568@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260820145237.531699751@linuxfoundation.org> References: <20260820145237.531699751@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 9f00f9cf2be293efe899db67dc5272e3a9c62717 ] __decode_pg_temp() decodes an user-controlled length but only rejects values large enough to overflow the allocation; it does not bound it to CEPH_PG_MAX_SIZE. The helper backs both pg_temp and pg_upmap decoding, and apply_upmap()/get_temp_osds() later copy the decoded list into the fixed-size on-stack array struct ceph_osds.osds[CEPH_PG_MAX_SIZE]. A monitor that sends an OSDMap with a pg_temp/pg_upmap entry longer than 32 thus causes a stack out-of-bounds write. An OSD set for a single PG can never exceed CEPH_PG_MAX_SIZE, so reject longer entries at decode time. The bound is well below the old overflow threshold, so it also covers the allocation-size overflow the previous check guarded against. BUG: KASAN: stack-out-of-bounds in ceph_pg_to_up_acting_osds Write of size 4 ... by task exploit kasan_report (mm/kasan/report.c:595) ceph_pg_to_up_acting_osds (net/ceph/osdmap.c:2617 net/ceph/osdmap.c:2833) calc_target (net/ceph/osd_client.c:1638) __submit_request (net/ceph/osd_client.c:2394) ceph_osdc_start_request (net/ceph/osd_client.c:2490) ceph_osdc_call (net/ceph/osd_client.c:5164) rbd_dev_image_probe (drivers/block/rbd.c:6899) do_rbd_add (drivers/block/rbd.c:7138) ... kernel BUG at net/ceph/osdmap.c:2670! [ idryomov: do the same in __decode_pg_upmap_items() ] Cc: stable@vger.kernel.org Fixes: a303bb0e5834 ("libceph: introduce and switch to decode_pg_mapping()") Reported-by: Weiming Shi Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Xiang Mei Reviewed-by: Alex Markuze Signed-off-by: Ilya Dryomov Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ceph/osdmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -1440,7 +1440,7 @@ static struct ceph_pg_mapping *__decode_ ceph_decode_32_safe(p, end, len, e_inval); if (len == 0 && incremental) return NULL; /* new_pg_temp: [] to remove */ - if ((size_t)len > (SIZE_MAX - sizeof(*pg)) / sizeof(u32)) + if (len > CEPH_PG_MAX_SIZE) return ERR_PTR(-EINVAL); ceph_decode_need(p, end, len * sizeof(u32), e_inval); @@ -1621,7 +1621,7 @@ static struct ceph_pg_mapping *__decode_ u32 len, i; ceph_decode_32_safe(p, end, len, e_inval); - if ((size_t)len > (SIZE_MAX - sizeof(*pg)) / (2 * sizeof(u32))) + if (len > CEPH_PG_MAX_SIZE) return ERR_PTR(-EINVAL); ceph_decode_need(p, end, 2 * len * sizeof(u32), e_inval);