From fd94d9dadee58e09b49075240fe83423eb1dcd36 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 5 Sep 2023 23:13:56 +0200 Subject: [PATCH 1/6] netfilter: nftables: exthdr: fix 4-byte stack OOB write If priv->len is a multiple of 4, then dst[len / 4] can write past the destination array which leads to stack corruption. This construct is necessary to clean the remainder of the register in case ->len is NOT a multiple of the register size, so make it conditional just like nft_payload.c does. The bug was added in 4.1 cycle and then copied/inherited when tcp/sctp and ip option support was added. Bug reported by Zero Day Initiative project (ZDI-CAN-21950, ZDI-CAN-21951, ZDI-CAN-21961). Fixes: 49499c3e6e18 ("netfilter: nf_tables: switch registers to 32 bit addressing") Fixes: 935b7f643018 ("netfilter: nft_exthdr: add TCP option matching") Fixes: 133dc203d77d ("netfilter: nft_exthdr: Support SCTP chunks") Fixes: dbb5281a1f84 ("netfilter: nf_tables: add support for matching IPv4 options") Signed-off-by: Florian Westphal --- net/netfilter/nft_exthdr.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c index a9844eefedebc..3fbaa7bf41f9c 100644 --- a/net/netfilter/nft_exthdr.c +++ b/net/netfilter/nft_exthdr.c @@ -35,6 +35,14 @@ static unsigned int optlen(const u8 *opt, unsigned int offset) return opt[offset + 1]; } +static int nft_skb_copy_to_reg(const struct sk_buff *skb, int offset, u32 *dest, unsigned int len) +{ + if (len % NFT_REG32_SIZE) + dest[len / NFT_REG32_SIZE] = 0; + + return skb_copy_bits(skb, offset, dest, len); +} + static void nft_exthdr_ipv6_eval(const struct nft_expr *expr, struct nft_regs *regs, const struct nft_pktinfo *pkt) @@ -56,8 +64,7 @@ static void nft_exthdr_ipv6_eval(const struct nft_expr *expr, } offset += priv->offset; - dest[priv->len / NFT_REG32_SIZE] = 0; - if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0) + if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0) goto err; return; err: @@ -153,8 +160,7 @@ static void nft_exthdr_ipv4_eval(const struct nft_expr *expr, } offset += priv->offset; - dest[priv->len / NFT_REG32_SIZE] = 0; - if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0) + if (nft_skb_copy_to_reg(pkt->skb, offset, dest, priv->len) < 0) goto err; return; err: @@ -210,7 +216,8 @@ static void nft_exthdr_tcp_eval(const struct nft_expr *expr, if (priv->flags & NFT_EXTHDR_F_PRESENT) { *dest = 1; } else { - dest[priv->len / NFT_REG32_SIZE] = 0; + if (priv->len % NFT_REG32_SIZE) + dest[priv->len / NFT_REG32_SIZE] = 0; memcpy(dest, opt + offset, priv->len); } @@ -388,9 +395,8 @@ static void nft_exthdr_sctp_eval(const struct nft_expr *expr, offset + ntohs(sch->length) > pkt->skb->len) break; - dest[priv->len / NFT_REG32_SIZE] = 0; - if (skb_copy_bits(pkt->skb, offset + priv->offset, - dest, priv->len) < 0) + if (nft_skb_copy_to_reg(pkt->skb, offset + priv->offset, + dest, priv->len) < 0) break; return; } From f4f8a7803119005e87b716874bec07c751efafec Mon Sep 17 00:00:00 2001 From: Wander Lairson Costa Date: Fri, 1 Sep 2023 10:50:20 -0300 Subject: [PATCH 2/6] netfilter: nfnetlink_osf: avoid OOB read The opt_num field is controlled by user mode and is not currently validated inside the kernel. An attacker can take advantage of this to trigger an OOB read and potentially leak information. BUG: KASAN: slab-out-of-bounds in nf_osf_match_one+0xbed/0xd10 net/netfilter/nfnetlink_osf.c:88 Read of size 2 at addr ffff88804bc64272 by task poc/6431 CPU: 1 PID: 6431 Comm: poc Not tainted 6.0.0-rc4 #1 Call Trace: nf_osf_match_one+0xbed/0xd10 net/netfilter/nfnetlink_osf.c:88 nf_osf_find+0x186/0x2f0 net/netfilter/nfnetlink_osf.c:281 nft_osf_eval+0x37f/0x590 net/netfilter/nft_osf.c:47 expr_call_ops_eval net/netfilter/nf_tables_core.c:214 nft_do_chain+0x2b0/0x1490 net/netfilter/nf_tables_core.c:264 nft_do_chain_ipv4+0x17c/0x1f0 net/netfilter/nft_chain_filter.c:23 [..] Also add validation to genre, subtype and version fields. Fixes: 11eeef41d5f6 ("netfilter: passive OS fingerprint xtables match") Reported-by: Lucas Leong Signed-off-by: Wander Lairson Costa Signed-off-by: Florian Westphal --- net/netfilter/nfnetlink_osf.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c index 8f1bfa6ccc2d9..50723ba082890 100644 --- a/net/netfilter/nfnetlink_osf.c +++ b/net/netfilter/nfnetlink_osf.c @@ -315,6 +315,14 @@ static int nfnl_osf_add_callback(struct sk_buff *skb, f = nla_data(osf_attrs[OSF_ATTR_FINGER]); + if (f->opt_num > ARRAY_SIZE(f->opt)) + return -EINVAL; + + if (!memchr(f->genre, 0, MAXGENRELEN) || + !memchr(f->subtype, 0, MAXGENRELEN) || + !memchr(f->version, 0, MAXGENRELEN)) + return -EINVAL; + kf = kmalloc(sizeof(struct nf_osf_finger), GFP_KERNEL); if (!kf) return -ENOMEM; From fdc04cc2d5fd0bb9c17f36d0a895cf3e151109e6 Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Fri, 1 Sep 2023 14:15:16 +0200 Subject: [PATCH 3/6] netfilter: nf_tables: uapi: Describe NFTA_RULE_CHAIN_ID Add a brief description to the enum's comment. Fixes: 837830a4b439 ("netfilter: nf_tables: add NFTA_RULE_CHAIN_ID attribute") Signed-off-by: Phil Sutter Signed-off-by: Florian Westphal --- include/uapi/linux/netfilter/nf_tables.h | 1 + 1 file changed, 1 insertion(+) diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 8466c2a9938f3..ca30232b7bc8a 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -263,6 +263,7 @@ enum nft_chain_attributes { * @NFTA_RULE_USERDATA: user data (NLA_BINARY, NFT_USERDATA_MAXLEN) * @NFTA_RULE_ID: uniquely identifies a rule in a transaction (NLA_U32) * @NFTA_RULE_POSITION_ID: transaction unique identifier of the previous rule (NLA_U32) + * @NFTA_RULE_CHAIN_ID: add the rule to chain by ID, alternative to @NFTA_RULE_CHAIN (NLA_U32) */ enum nft_rule_attributes { NFTA_RULE_UNSPEC, From 2ee52ae94baabf7ee09cf2a8d854b990dac5d0e4 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 4 Sep 2023 02:14:36 +0200 Subject: [PATCH 4/6] netfilter: nft_set_rbtree: skip sync GC for new elements in this transaction New elements in this transaction might expired before such transaction ends. Skip sync GC for such elements otherwise commit path might walk over an already released object. Once transaction is finished, async GC will collect such expired element. Fixes: f6c383b8c31a ("netfilter: nf_tables: adapt set backend to use GC transaction API") Signed-off-by: Pablo Neira Ayuso Signed-off-by: Florian Westphal --- net/netfilter/nft_set_rbtree.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c index c6435e7092319..f250b5399344a 100644 --- a/net/netfilter/nft_set_rbtree.c +++ b/net/netfilter/nft_set_rbtree.c @@ -312,6 +312,7 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set, struct nft_rbtree_elem *rbe, *rbe_le = NULL, *rbe_ge = NULL; struct rb_node *node, *next, *parent, **p, *first = NULL; struct nft_rbtree *priv = nft_set_priv(set); + u8 cur_genmask = nft_genmask_cur(net); u8 genmask = nft_genmask_next(net); int d, err; @@ -357,8 +358,11 @@ static int __nft_rbtree_insert(const struct net *net, const struct nft_set *set, if (!nft_set_elem_active(&rbe->ext, genmask)) continue; - /* perform garbage collection to avoid bogus overlap reports. */ - if (nft_set_elem_expired(&rbe->ext)) { + /* perform garbage collection to avoid bogus overlap reports + * but skip new elements in this transaction. + */ + if (nft_set_elem_expired(&rbe->ext) && + nft_set_elem_active(&rbe->ext, cur_genmask)) { err = nft_rbtree_gc_elem(set, priv, rbe, genmask); if (err < 0) return err; From 050d91c03b28ca479df13dfb02bcd2c60dd6a878 Mon Sep 17 00:00:00 2001 From: Kyle Zeng Date: Tue, 5 Sep 2023 15:04:09 -0700 Subject: [PATCH 5/6] netfilter: ipset: add the missing IP_SET_HASH_WITH_NET0 macro for ip_set_hash_netportnet.c The missing IP_SET_HASH_WITH_NET0 macro in ip_set_hash_netportnet can lead to the use of wrong `CIDR_POS(c)` for calculating array offsets, which can lead to integer underflow. As a result, it leads to slab out-of-bound access. This patch adds back the IP_SET_HASH_WITH_NET0 macro to ip_set_hash_netportnet to address the issue. Fixes: 886503f34d63 ("netfilter: ipset: actually allow allowable CIDR 0 in hash:net,port,net") Suggested-by: Jozsef Kadlecsik Signed-off-by: Kyle Zeng Acked-by: Jozsef Kadlecsik Signed-off-by: Florian Westphal --- net/netfilter/ipset/ip_set_hash_netportnet.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/netfilter/ipset/ip_set_hash_netportnet.c b/net/netfilter/ipset/ip_set_hash_netportnet.c index 005a7ce87217e..bf4f91b78e1dc 100644 --- a/net/netfilter/ipset/ip_set_hash_netportnet.c +++ b/net/netfilter/ipset/ip_set_hash_netportnet.c @@ -36,6 +36,7 @@ MODULE_ALIAS("ip_set_hash:net,port,net"); #define IP_SET_HASH_WITH_PROTO #define IP_SET_HASH_WITH_NETS #define IPSET_NET_COUNT 2 +#define IP_SET_HASH_WITH_NET0 /* IPv4 variant */ From 9b5ba5c9c5109bf89dc64a3f4734bd125d1ce52e Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 6 Sep 2023 11:42:02 +0200 Subject: [PATCH 6/6] netfilter: nf_tables: Unbreak audit log reset Deliver audit log from __nf_tables_dump_rules(), table dereference at the end of the table list loop might point to the list head, leading to this crash. [ 4137.407349] BUG: unable to handle page fault for address: 00000000001f3c50 [ 4137.407357] #PF: supervisor read access in kernel mode [ 4137.407359] #PF: error_code(0x0000) - not-present page [ 4137.407360] PGD 0 P4D 0 [ 4137.407363] Oops: 0000 [#1] PREEMPT SMP PTI [ 4137.407365] CPU: 4 PID: 500177 Comm: nft Not tainted 6.5.0+ #277 [ 4137.407369] RIP: 0010:string+0x49/0xd0 [ 4137.407374] Code: ff 77 36 45 89 d1 31 f6 49 01 f9 66 45 85 d2 75 19 eb 1e 49 39 f8 76 02 88 07 48 83 c7 01 83 c6 01 48 83 c2 01 4c 39 cf 74 07 <0f> b6 02 84 c0 75 e2 4c 89 c2 e9 58 e5 ff ff 48 c7 c0 0e b2 ff 81 [ 4137.407377] RSP: 0018:ffff8881179737f0 EFLAGS: 00010286 [ 4137.407379] RAX: 00000000001f2c50 RBX: ffff888117973848 RCX: ffff0a00ffffff04 [ 4137.407380] RDX: 00000000001f3c50 RSI: 0000000000000000 RDI: 0000000000000000 [ 4137.407381] RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000ffffffff [ 4137.407383] R10: ffffffffffffffff R11: ffff88813584d200 R12: 0000000000000000 [ 4137.407384] R13: ffffffffa15cf709 R14: 0000000000000000 R15: ffffffffa15cf709 [ 4137.407385] FS: 00007fcfc18bb580(0000) GS:ffff88840e700000(0000) knlGS:0000000000000000 [ 4137.407387] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4137.407388] CR2: 00000000001f3c50 CR3: 00000001055b2001 CR4: 00000000001706e0 [ 4137.407390] Call Trace: [ 4137.407392] [ 4137.407393] ? __die+0x1b/0x60 [ 4137.407397] ? page_fault_oops+0x6b/0xa0 [ 4137.407399] ? exc_page_fault+0x60/0x120 [ 4137.407403] ? asm_exc_page_fault+0x22/0x30 [ 4137.407408] ? string+0x49/0xd0 [ 4137.407410] vsnprintf+0x257/0x4f0 [ 4137.407414] kvasprintf+0x3e/0xb0 [ 4137.407417] kasprintf+0x3e/0x50 [ 4137.407419] nf_tables_dump_rules+0x1c0/0x360 [nf_tables] [ 4137.407439] ? __alloc_skb+0xc3/0x170 [ 4137.407442] netlink_dump+0x170/0x330 [ 4137.407447] __netlink_dump_start+0x227/0x300 [ 4137.407449] nf_tables_getrule+0x205/0x390 [nf_tables] Deliver audit log only once at the end of the rule dump+reset for consistency with the set dump+reset. Ensure audit reset access to table under rcu read side lock. The table list iteration holds rcu read lock side, but recent audit code dereferences table object out of the rcu read lock side. Fixes: ea078ae9108e ("netfilter: nf_tables: Audit log rule reset") Fixes: 7e9be1124dbe ("netfilter: nf_tables: Audit log setelem reset") Signed-off-by: Pablo Neira Ayuso Acked-by: Phil Sutter Signed-off-by: Florian Westphal --- net/netfilter/nf_tables_api.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 2c81cee858d62..e429ebba74b3d 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -3480,6 +3480,10 @@ static int __nf_tables_dump_rules(struct sk_buff *skb, cont_skip: (*idx)++; } + + if (reset && *idx) + audit_log_rule_reset(table, cb->seq, *idx); + return 0; } @@ -3540,9 +3544,6 @@ static int nf_tables_dump_rules(struct sk_buff *skb, done: rcu_read_unlock(); - if (reset && idx > cb->args[0]) - audit_log_rule_reset(table, cb->seq, idx - cb->args[0]); - cb->args[0] = idx; return skb->len; } @@ -5760,8 +5761,6 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb) if (!args.iter.err && args.iter.count == cb->args[0]) args.iter.err = nft_set_catchall_dump(net, skb, set, reset, cb->seq); - rcu_read_unlock(); - nla_nest_end(skb, nest); nlmsg_end(skb, nlh); @@ -5769,6 +5768,8 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb) audit_log_nft_set_reset(table, cb->seq, args.iter.count - args.iter.skip); + rcu_read_unlock(); + if (args.iter.err && args.iter.err != -EMSGSIZE) return args.iter.err; if (args.iter.count == cb->args[0])