On Tue, Nov 05, 2024 at 12:09:49PM -0800, Casey Schaufler wrote: > On 11/5/2024 3:12 AM, Pablo Neira Ayuso wrote: > > Hi, > > > > There is another issue in this recent series, see below. > > > > This needs another follow up. > > Dan Carpenter sent a patch: > > https://lore.kernel.org/lkml/b226a01a-2545-4b67-9cc6-59cfa0ffabbc@xxxxxxxxxxxxxxxx/ > Sorry for the confusion. That was for a separate simpler issue. I was confused about this line here. 785 if (seclen && nla_put(skb, NFQA_SECCTX, ctx.len, ctx.context)) regards, dan carpenter > > > > Thanks. > > > > On Sat, Nov 02, 2024 at 12:21:01PM +0300, Dan Carpenter wrote: > >> Hello Casey Schaufler, > >> > >> Commit 95a3c11eb670 ("lsm: replace context+len with lsm_context") > >> from Oct 23, 2024 (linux-next), leads to the following Smatch static > >> checker warning: > >> > >> net/netfilter/nfnetlink_queue.c:646 nfqnl_build_packet_message() > >> warn: always true condition '(seclen >= 0) => (0-u32max >= 0)' > >> > >> net/netfilter/nfnetlink_queue.c:813 nfqnl_build_packet_message() > >> warn: always true condition '(seclen >= 0) => (0-u32max >= 0)' > >> > >> net/netfilter/nfnetlink_queue.c:822 nfqnl_build_packet_message() > >> warn: always true condition '(seclen >= 0) => (0-u32max >= 0)' > >> > >> net/netfilter/nfnetlink_queue.c > >> 551 static struct sk_buff * > >> 552 nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, > >> 553 struct nf_queue_entry *entry, > >> 554 __be32 **packet_id_ptr) > >> 555 { > >> 556 size_t size; > >> 557 size_t data_len = 0, cap_len = 0; > >> 558 unsigned int hlen = 0; > >> 559 struct sk_buff *skb; > >> 560 struct nlattr *nla; > >> 561 struct nfqnl_msg_packet_hdr *pmsg; > >> 562 struct nlmsghdr *nlh; > >> 563 struct sk_buff *entskb = entry->skb; > >> 564 struct net_device *indev; > >> 565 struct net_device *outdev; > >> 566 struct nf_conn *ct = NULL; > >> 567 enum ip_conntrack_info ctinfo = 0; > >> 568 const struct nfnl_ct_hook *nfnl_ct; > >> 569 bool csum_verify; > >> 570 struct lsm_context ctx; > >> 571 u32 seclen = 0; > >> ^^^^^^^^^^ > >> > >> 572 ktime_t tstamp; > >> 573 > >> 574 size = nlmsg_total_size(sizeof(struct nfgenmsg)) > >> 575 + nla_total_size(sizeof(struct nfqnl_msg_packet_hdr)) > >> 576 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ > >> 577 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ > >> 578 #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) > >> 579 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ > >> 580 + nla_total_size(sizeof(u_int32_t)) /* ifindex */ > >> 581 #endif > >> 582 + nla_total_size(sizeof(u_int32_t)) /* mark */ > >> 583 + nla_total_size(sizeof(u_int32_t)) /* priority */ > >> 584 + nla_total_size(sizeof(struct nfqnl_msg_packet_hw)) > >> 585 + nla_total_size(sizeof(u_int32_t)) /* skbinfo */ > >> 586 #if IS_ENABLED(CONFIG_CGROUP_NET_CLASSID) > >> 587 + nla_total_size(sizeof(u_int32_t)) /* classid */ > >> 588 #endif > >> 589 + nla_total_size(sizeof(u_int32_t)); /* cap_len */ > >> 590 > >> 591 tstamp = skb_tstamp_cond(entskb, false); > >> 592 if (tstamp) > >> 593 size += nla_total_size(sizeof(struct nfqnl_msg_packet_timestamp)); > >> 594 > >> 595 size += nfqnl_get_bridge_size(entry); > >> 596 > >> 597 if (entry->state.hook <= NF_INET_FORWARD || > >> 598 (entry->state.hook == NF_INET_POST_ROUTING && entskb->sk == NULL)) > >> 599 csum_verify = !skb_csum_unnecessary(entskb); > >> 600 else > >> 601 csum_verify = false; > >> 602 > >> 603 outdev = entry->state.out; > >> 604 > >> 605 switch ((enum nfqnl_config_mode)READ_ONCE(queue->copy_mode)) { > >> 606 case NFQNL_COPY_META: > >> 607 case NFQNL_COPY_NONE: > >> 608 break; > >> 609 > >> 610 case NFQNL_COPY_PACKET: > >> 611 if (!(queue->flags & NFQA_CFG_F_GSO) && > >> 612 entskb->ip_summed == CHECKSUM_PARTIAL && > >> 613 nf_queue_checksum_help(entskb)) > >> 614 return NULL; > >> 615 > >> 616 data_len = READ_ONCE(queue->copy_range); > >> 617 if (data_len > entskb->len) > >> 618 data_len = entskb->len; > >> 619 > >> 620 hlen = skb_zerocopy_headlen(entskb); > >> 621 hlen = min_t(unsigned int, hlen, data_len); > >> 622 size += sizeof(struct nlattr) + hlen; > >> 623 cap_len = entskb->len; > >> 624 break; > >> 625 } > >> 626 > >> 627 nfnl_ct = rcu_dereference(nfnl_ct_hook); > >> 628 > >> 629 #if IS_ENABLED(CONFIG_NF_CONNTRACK) > >> 630 if (queue->flags & NFQA_CFG_F_CONNTRACK) { > >> 631 if (nfnl_ct != NULL) { > >> 632 ct = nf_ct_get(entskb, &ctinfo); > >> 633 if (ct != NULL) > >> 634 size += nfnl_ct->build_size(ct); > >> 635 } > >> 636 } > >> 637 #endif > >> 638 > >> 639 if (queue->flags & NFQA_CFG_F_UID_GID) { > >> 640 size += (nla_total_size(sizeof(u_int32_t)) /* uid */ > >> 641 + nla_total_size(sizeof(u_int32_t))); /* gid */ > >> 642 } > >> 643 > >> 644 if ((queue->flags & NFQA_CFG_F_SECCTX) && entskb->sk) { > >> 645 seclen = nfqnl_get_sk_secctx(entskb, &ctx); > >> > >> nfqnl_get_sk_secctx() returns negative error codes. It needs to be changed ot > >> int as well instead of u32. > >> > >> 646 if (seclen >= 0) > >> 647 size += nla_total_size(seclen); > >> 648 } > >> 649 > >> 650 skb = alloc_skb(size, GFP_ATOMIC); > >> 651 if (!skb) { > >> 652 skb_tx_error(entskb); > >> 653 goto nlmsg_failure; > >> 654 } > >> 655 > >> 656 nlh = nfnl_msg_put(skb, 0, 0, > >> 657 nfnl_msg_type(NFNL_SUBSYS_QUEUE, NFQNL_MSG_PACKET), > >> 658 0, entry->state.pf, NFNETLINK_V0, > >> 659 htons(queue->queue_num)); > >> 660 if (!nlh) { > >> 661 skb_tx_error(entskb); > >> 662 kfree_skb(skb); > >> 663 goto nlmsg_failure; > >> 664 } > >> 665 > >> 666 nla = __nla_reserve(skb, NFQA_PACKET_HDR, sizeof(*pmsg)); > >> 667 pmsg = nla_data(nla); > >> 668 pmsg->hw_protocol = entskb->protocol; > >> 669 pmsg->hook = entry->state.hook; > >> 670 *packet_id_ptr = &pmsg->packet_id; > >> 671 > >> 672 indev = entry->state.in; > >> 673 if (indev) { > >> 674 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) > >> 675 if (nla_put_be32(skb, NFQA_IFINDEX_INDEV, htonl(indev->ifindex))) > >> 676 goto nla_put_failure; > >> 677 #else > >> 678 if (entry->state.pf == PF_BRIDGE) { > >> 679 /* Case 1: indev is physical input device, we need to > >> 680 * look for bridge group (when called from > >> 681 * netfilter_bridge) */ > >> 682 if (nla_put_be32(skb, NFQA_IFINDEX_PHYSINDEV, > >> 683 htonl(indev->ifindex)) || > >> 684 /* this is the bridge group "brX" */ > >> 685 /* rcu_read_lock()ed by __nf_queue */ > >> 686 nla_put_be32(skb, NFQA_IFINDEX_INDEV, > >> 687 htonl(br_port_get_rcu(indev)->br->dev->ifindex))) > >> 688 goto nla_put_failure; > >> 689 } else { > >> 690 int physinif; > >> 691 > >> 692 /* Case 2: indev is bridge group, we need to look for > >> 693 * physical device (when called from ipv4) */ > >> 694 if (nla_put_be32(skb, NFQA_IFINDEX_INDEV, > >> 695 htonl(indev->ifindex))) > >> 696 goto nla_put_failure; > >> 697 > >> 698 physinif = nf_bridge_get_physinif(entskb); > >> 699 if (physinif && > >> 700 nla_put_be32(skb, NFQA_IFINDEX_PHYSINDEV, > >> 701 htonl(physinif))) > >> 702 goto nla_put_failure; > >> 703 } > >> 704 #endif > >> 705 } > >> 706 > >> 707 if (outdev) { > >> 708 #if !IS_ENABLED(CONFIG_BRIDGE_NETFILTER) > >> 709 if (nla_put_be32(skb, NFQA_IFINDEX_OUTDEV, htonl(outdev->ifindex))) > >> 710 goto nla_put_failure; > >> 711 #else > >> 712 if (entry->state.pf == PF_BRIDGE) { > >> 713 /* Case 1: outdev is physical output device, we need to > >> 714 * look for bridge group (when called from > >> 715 * netfilter_bridge) */ > >> 716 if (nla_put_be32(skb, NFQA_IFINDEX_PHYSOUTDEV, > >> 717 htonl(outdev->ifindex)) || > >> 718 /* this is the bridge group "brX" */ > >> 719 /* rcu_read_lock()ed by __nf_queue */ > >> 720 nla_put_be32(skb, NFQA_IFINDEX_OUTDEV, > >> 721 htonl(br_port_get_rcu(outdev)->br->dev->ifindex))) > >> 722 goto nla_put_failure; > >> 723 } else { > >> 724 int physoutif; > >> 725 > >> 726 /* Case 2: outdev is bridge group, we need to look for > >> 727 * physical output device (when called from ipv4) */ > >> 728 if (nla_put_be32(skb, NFQA_IFINDEX_OUTDEV, > >> 729 htonl(outdev->ifindex))) > >> 730 goto nla_put_failure; > >> 731 > >> 732 physoutif = nf_bridge_get_physoutif(entskb); > >> 733 if (physoutif && > >> 734 nla_put_be32(skb, NFQA_IFINDEX_PHYSOUTDEV, > >> 735 htonl(physoutif))) > >> 736 goto nla_put_failure; > >> 737 } > >> 738 #endif > >> 739 } > >> 740 > >> 741 if (entskb->mark && > >> 742 nla_put_be32(skb, NFQA_MARK, htonl(entskb->mark))) > >> 743 goto nla_put_failure; > >> 744 > >> 745 if (entskb->priority && > >> 746 nla_put_be32(skb, NFQA_PRIORITY, htonl(entskb->priority))) > >> 747 goto nla_put_failure; > >> 748 > >> 749 if (indev && entskb->dev && > >> 750 skb_mac_header_was_set(entskb) && > >> 751 skb_mac_header_len(entskb) != 0) { > >> 752 struct nfqnl_msg_packet_hw phw; > >> 753 int len; > >> 754 > >> 755 memset(&phw, 0, sizeof(phw)); > >> 756 len = dev_parse_header(entskb, phw.hw_addr); > >> 757 if (len) { > >> 758 phw.hw_addrlen = htons(len); > >> 759 if (nla_put(skb, NFQA_HWADDR, sizeof(phw), &phw)) > >> 760 goto nla_put_failure; > >> 761 } > >> 762 } > >> 763 > >> 764 if (nfqnl_put_bridge(entry, skb) < 0) > >> 765 goto nla_put_failure; > >> 766 > >> 767 if (entry->state.hook <= NF_INET_FORWARD && tstamp) { > >> 768 struct nfqnl_msg_packet_timestamp ts; > >> 769 struct timespec64 kts = ktime_to_timespec64(tstamp); > >> 770 > >> 771 ts.sec = cpu_to_be64(kts.tv_sec); > >> 772 ts.usec = cpu_to_be64(kts.tv_nsec / NSEC_PER_USEC); > >> 773 > >> 774 if (nla_put(skb, NFQA_TIMESTAMP, sizeof(ts), &ts)) > >> 775 goto nla_put_failure; > >> 776 } > >> 777 > >> 778 if ((queue->flags & NFQA_CFG_F_UID_GID) && entskb->sk && > >> 779 nfqnl_put_sk_uidgid(skb, entskb->sk) < 0) > >> 780 goto nla_put_failure; > >> 781 > >> 782 if (nfqnl_put_sk_classid(skb, entskb->sk) < 0) > >> 783 goto nla_put_failure; > >> 784 > >> 785 if (seclen && nla_put(skb, NFQA_SECCTX, ctx.len, ctx.context)) > >> ^^^^^^ > >> This doesn't look right. > >> > >> > >> 786 goto nla_put_failure; > >> 787 > >> 788 if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0) > >> 789 goto nla_put_failure; > >> 790 > >> 791 if (cap_len > data_len && > >> 792 nla_put_be32(skb, NFQA_CAP_LEN, htonl(cap_len))) > >> 793 goto nla_put_failure; > >> 794 > >> 795 if (nfqnl_put_packet_info(skb, entskb, csum_verify)) > >> 796 goto nla_put_failure; > >> 797 > >> 798 if (data_len) { > >> 799 struct nlattr *nla; > >> 800 > >> 801 if (skb_tailroom(skb) < sizeof(*nla) + hlen) > >> 802 goto nla_put_failure; > >> 803 > >> 804 nla = skb_put(skb, sizeof(*nla)); > >> 805 nla->nla_type = NFQA_PAYLOAD; > >> 806 nla->nla_len = nla_attr_size(data_len); > >> 807 > >> 808 if (skb_zerocopy(skb, entskb, data_len, hlen)) > >> 809 goto nla_put_failure; > >> 810 } > >> 811 > >> 812 nlh->nlmsg_len = skb->len; > >> 813 if (seclen >= 0) > >> ^^^^^^^^^^^ > >> > >> 814 security_release_secctx(&ctx); > >> 815 return skb; > >> 816 > >> 817 nla_put_failure: > >> 818 skb_tx_error(entskb); > >> 819 kfree_skb(skb); > >> 820 net_err_ratelimited("nf_queue: error creating packet message\n"); > >> 821 nlmsg_failure: > >> 822 if (seclen >= 0) > >> ^^^^^^^^^^^ > >> > >> 823 security_release_secctx(&ctx); > >> 824 return NULL; > >> 825 } > >> > >> > >> > >> regards, > >> dan carpenter > >>
