From patchwork Wed Jul 5 12:15:15 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thadeu Lima de Souza Cascardo X-Patchwork-Id: 13302118 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 9A96F53BA for ; Wed, 5 Jul 2023 12:16:17 +0000 (UTC) Received: from smtp-relay-canonical-1.canonical.com (smtp-relay-canonical-1.canonical.com [185.125.188.121]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAE33BE; Wed, 5 Jul 2023 05:16:14 -0700 (PDT) Received: from localhost.localdomain (1.general.cascardo.us.vpn [10.172.70.58]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id 19DE943085; Wed, 5 Jul 2023 12:16:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1688559372; bh=O9vr0VMerEwzGkK8Z08zPO8WL18o7vrMAu8TdG+o5wA=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=auTpJPlOboAuDdSBn+R+m87tXMZ7sJ8ME6C/00caCG4diq6jGK01q2y+CTMBw9udG mbFYcIuyJgGkTdOb62ivb7rg0TQszDPrvvxZEkGXZRcLw+/VHeIWrnlrxzowf+FO+w KiS2Z/zFaz78IiqA5REYbIKZ3/f6Mw2KnGuh7HkiwwNVlBIbLyTNqq+TSEDuWadPBe gTQakgoE4TI1WpO1l/4SyvCOPH59zxwWUVgNp5xc4WNid08ZH1FOyLBDhdOYpRCYrE 7riuBlBKvI/c8jg3UyugKy4/bpMEhtP5lv4aTUv7liegEPEcaV8OWxyJ76QmKgF1ln Mhl/fv/WGGXCw== From: Thadeu Lima de Souza Cascardo To: netfilter-devel@vger.kernel.org Cc: cascardo@canonical.com, netdev@vger.kernel.org, Pablo Neira Ayuso Subject: [PATCH] netfilter: nf_tables: prevent OOB access in nft_byteorder_eval Date: Wed, 5 Jul 2023 09:15:15 -0300 Message-Id: <20230705121515.747251-1-cascardo@canonical.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org When evaluating byteorder expressions with size 2, a union with 32-bit and 16-bit members is used. Since the 16-bit members are aligned to 32-bit, the array accesses will be out-of-bounds. It may lead to a stack-out-of-bounds access like the one below: [ 23.095215] ================================================================== [ 23.095625] BUG: KASAN: stack-out-of-bounds in nft_byteorder_eval+0x13c/0x320 [ 23.096020] Read of size 2 at addr ffffc90000007948 by task ping/115 [ 23.096358] [ 23.096456] CPU: 0 PID: 115 Comm: ping Not tainted 6.4.0+ #413 [ 23.096770] Call Trace: [ 23.096910] [ 23.097030] dump_stack_lvl+0x60/0xc0 [ 23.097218] print_report+0xcf/0x630 [ 23.097388] ? nft_byteorder_eval+0x13c/0x320 [ 23.097577] ? kasan_addr_to_slab+0xd/0xc0 [ 23.097760] ? nft_byteorder_eval+0x13c/0x320 [ 23.097949] kasan_report+0xc9/0x110 [ 23.098106] ? nft_byteorder_eval+0x13c/0x320 [ 23.098298] __asan_load2+0x83/0xd0 [ 23.098453] nft_byteorder_eval+0x13c/0x320 [ 23.098659] nft_do_chain+0x1c8/0xc50 [ 23.098852] ? __pfx_nft_do_chain+0x10/0x10 [ 23.099078] ? __kasan_check_read+0x11/0x20 [ 23.099295] ? __pfx___lock_acquire+0x10/0x10 [ 23.099535] ? __pfx___lock_acquire+0x10/0x10 [ 23.099745] ? __kasan_check_read+0x11/0x20 [ 23.099929] nft_do_chain_ipv4+0xfe/0x140 [ 23.100105] ? __pfx_nft_do_chain_ipv4+0x10/0x10 [ 23.100327] ? lock_release+0x204/0x400 [ 23.100515] ? nf_hook.constprop.0+0x340/0x550 [ 23.100779] nf_hook_slow+0x6c/0x100 [ 23.100977] ? __pfx_nft_do_chain_ipv4+0x10/0x10 [ 23.101223] nf_hook.constprop.0+0x334/0x550 [ 23.101443] ? __pfx_ip_local_deliver_finish+0x10/0x10 [ 23.101677] ? __pfx_nf_hook.constprop.0+0x10/0x10 [ 23.101882] ? __pfx_ip_rcv_finish+0x10/0x10 [ 23.102071] ? __pfx_ip_local_deliver_finish+0x10/0x10 [ 23.102291] ? rcu_read_lock_held+0x4b/0x70 [ 23.102481] ip_local_deliver+0xbb/0x110 [ 23.102665] ? __pfx_ip_rcv+0x10/0x10 [ 23.102839] ip_rcv+0x199/0x2a0 [ 23.102980] ? __pfx_ip_rcv+0x10/0x10 [ 23.103140] __netif_receive_skb_one_core+0x13e/0x150 [ 23.103362] ? __pfx___netif_receive_skb_one_core+0x10/0x10 [ 23.103647] ? mark_held_locks+0x48/0xa0 [ 23.103819] ? process_backlog+0x36c/0x380 [ 23.103999] __netif_receive_skb+0x23/0xc0 [ 23.104179] process_backlog+0x91/0x380 [ 23.104350] __napi_poll.constprop.0+0x66/0x360 [ 23.104589] ? net_rx_action+0x1cb/0x610 [ 23.104811] net_rx_action+0x33e/0x610 [ 23.105024] ? _raw_spin_unlock+0x23/0x50 [ 23.105257] ? __pfx_net_rx_action+0x10/0x10 [ 23.105485] ? mark_held_locks+0x48/0xa0 [ 23.105741] __do_softirq+0xfa/0x5ab [ 23.105956] ? __dev_queue_xmit+0x765/0x1c00 [ 23.106193] do_softirq.part.0+0x49/0xc0 [ 23.106423] [ 23.106547] [ 23.106670] __local_bh_enable_ip+0xf5/0x120 [ 23.106903] __dev_queue_xmit+0x789/0x1c00 [ 23.107131] ? __pfx___dev_queue_xmit+0x10/0x10 [ 23.107381] ? find_held_lock+0x8e/0xb0 [ 23.107585] ? lock_release+0x204/0x400 [ 23.107798] ? neigh_resolve_output+0x185/0x350 [ 23.108049] ? mark_held_locks+0x48/0xa0 [ 23.108265] ? neigh_resolve_output+0x185/0x350 [ 23.108514] neigh_resolve_output+0x246/0x350 [ 23.108753] ? neigh_resolve_output+0x246/0x350 [ 23.109003] ip_finish_output2+0x3c3/0x10b0 [ 23.109250] ? __pfx_ip_finish_output2+0x10/0x10 [ 23.109510] ? __pfx_nf_hook+0x10/0x10 [ 23.109732] __ip_finish_output+0x217/0x390 [ 23.109978] ip_finish_output+0x2f/0x130 [ 23.110207] ip_output+0xc9/0x170 [ 23.110404] ip_push_pending_frames+0x1a0/0x240 [ 23.110652] raw_sendmsg+0x102e/0x19e0 [ 23.110871] ? __pfx_raw_sendmsg+0x10/0x10 [ 23.111093] ? lock_release+0x204/0x400 [ 23.111304] ? __mod_lruvec_page_state+0x148/0x330 [ 23.111567] ? find_held_lock+0x8e/0xb0 [ 23.111777] ? find_held_lock+0x8e/0xb0 [ 23.111993] ? __rcu_read_unlock+0x7c/0x2f0 [ 23.112225] ? aa_sk_perm+0x18a/0x550 [ 23.112431] ? filemap_map_pages+0x4f1/0x900 [ 23.112665] ? __pfx_aa_sk_perm+0x10/0x10 [ 23.112880] ? find_held_lock+0x8e/0xb0 [ 23.113098] inet_sendmsg+0xa0/0xb0 [ 23.113297] ? inet_sendmsg+0xa0/0xb0 [ 23.113500] ? __pfx_inet_sendmsg+0x10/0x10 [ 23.113727] sock_sendmsg+0xf4/0x100 [ 23.113924] ? move_addr_to_kernel.part.0+0x4f/0xa0 [ 23.114190] __sys_sendto+0x1d4/0x290 [ 23.114391] ? __pfx___sys_sendto+0x10/0x10 [ 23.114621] ? __pfx_mark_lock.part.0+0x10/0x10 [ 23.114869] ? lock_release+0x204/0x400 [ 23.115076] ? find_held_lock+0x8e/0xb0 [ 23.115287] ? rcu_is_watching+0x23/0x60 [ 23.115503] ? __rseq_handle_notify_resume+0x6e2/0x860 [ 23.115778] ? __kasan_check_write+0x14/0x30 [ 23.116008] ? blkcg_maybe_throttle_current+0x8d/0x770 [ 23.116285] ? mark_held_locks+0x28/0xa0 [ 23.116503] ? do_syscall_64+0x37/0x90 [ 23.116713] __x64_sys_sendto+0x7f/0xb0 [ 23.116924] do_syscall_64+0x59/0x90 [ 23.117123] ? irqentry_exit_to_user_mode+0x25/0x30 [ 23.117387] ? irqentry_exit+0x77/0xb0 [ 23.117593] ? exc_page_fault+0x92/0x140 [ 23.117806] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 [ 23.118081] RIP: 0033:0x7f744aee2bba [ 23.118282] Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89 [ 23.119237] RSP: 002b:00007ffd04a7c9f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c [ 23.119644] RAX: ffffffffffffffda RBX: 00007ffd04a7e0a0 RCX: 00007f744aee2bba [ 23.120023] RDX: 0000000000000040 RSI: 000056488e9e6300 RDI: 0000000000000003 [ 23.120413] RBP: 000056488e9e6300 R08: 00007ffd04a80320 R09: 0000000000000010 [ 23.120809] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000040 [ 23.121219] R13: 00007ffd04a7dc38 R14: 00007ffd04a7ca00 R15: 00007ffd04a7e0a0 [ 23.121617] [ 23.121749] [ 23.121845] The buggy address belongs to the virtual mapping at [ 23.121845] [ffffc90000000000, ffffc90000009000) created by: [ 23.121845] irq_init_percpu_irqstack+0x1cf/0x270 [ 23.122707] [ 23.122803] The buggy address belongs to the physical page: [ 23.123104] page:0000000072ac19f0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24a09 [ 23.123609] flags: 0xfffffc0001000(reserved|node=0|zone=1|lastcpupid=0x1fffff) [ 23.123998] page_type: 0xffffffff() [ 23.124194] raw: 000fffffc0001000 ffffea0000928248 ffffea0000928248 0000000000000000 [ 23.124610] raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000 [ 23.125023] page dumped because: kasan: bad access detected [ 23.125326] [ 23.125421] Memory state around the buggy address: [ 23.125682] ffffc90000007800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 23.126072] ffffc90000007880: 00 00 00 00 00 f1 f1 f1 f1 f1 f1 00 00 f2 f2 00 [ 23.126455] >ffffc90000007900: 00 00 00 00 00 00 00 00 00 f2 f2 f2 f2 00 00 00 [ 23.126840] ^ [ 23.127138] ffffc90000007980: 00 00 00 00 00 00 00 00 00 00 00 00 00 f3 f3 f3 [ 23.127522] ffffc90000007a00: f3 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 [ 23.127906] ================================================================== [ 23.128324] Disabling lock debugging due to kernel taint Using simple s32 and s16 pointers for each of these accesses fixes the problem. Fixes: 96518518cc41 ("netfilter: add nftables") Cc: stable@vger.kernel.org Reported-by: Tanguy DUBROCA (@SidewayRE) from @Synacktiv working with ZDI Signed-off-by: Thadeu Lima de Souza Cascardo --- net/netfilter/nft_byteorder.c | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) diff --git a/net/netfilter/nft_byteorder.c b/net/netfilter/nft_byteorder.c index 9a85e797ed58..aa16bd2e92e2 100644 --- a/net/netfilter/nft_byteorder.c +++ b/net/netfilter/nft_byteorder.c @@ -30,11 +30,14 @@ void nft_byteorder_eval(const struct nft_expr *expr, const struct nft_byteorder *priv = nft_expr_priv(expr); u32 *src = ®s->data[priv->sreg]; u32 *dst = ®s->data[priv->dreg]; - union { u32 u32; u16 u16; } *s, *d; + u32 *s32, *d32; + u16 *s16, *d16; unsigned int i; - s = (void *)src; - d = (void *)dst; + s32 = (void *)src; + d32 = (void *)dst; + s16 = (void *)src; + d16 = (void *)dst; switch (priv->size) { case 8: { @@ -62,11 +65,11 @@ void nft_byteorder_eval(const struct nft_expr *expr, switch (priv->op) { case NFT_BYTEORDER_NTOH: for (i = 0; i < priv->len / 4; i++) - d[i].u32 = ntohl((__force __be32)s[i].u32); + d32[i] = ntohl((__force __be32)s32[i]); break; case NFT_BYTEORDER_HTON: for (i = 0; i < priv->len / 4; i++) - d[i].u32 = (__force __u32)htonl(s[i].u32); + d32[i] = (__force __u32)htonl(s32[i]); break; } break; @@ -74,11 +77,11 @@ void nft_byteorder_eval(const struct nft_expr *expr, switch (priv->op) { case NFT_BYTEORDER_NTOH: for (i = 0; i < priv->len / 2; i++) - d[i].u16 = ntohs((__force __be16)s[i].u16); + d16[i] = ntohs((__force __be16)s16[i]); break; case NFT_BYTEORDER_HTON: for (i = 0; i < priv->len / 2; i++) - d[i].u16 = (__force __u16)htons(s[i].u16); + d16[i] = (__force __u16)htons(s16[i]); break; } break;