diff mbox series

[net,3/3] netfilter: nft_tunnel: fix geneve_opt type confusion addition

Message ID 20250403115752.19608-4-pablo@netfilter.org (mailing list archive)
State Accepted
Commit 1b755d8eb1ace3870789d48fbd94f386ad6e30be
Delegated to: Netdev Maintainers
Headers show
Series [net,1/3] netfilter: nft_set_hash: GC reaps elements with conncount for dynamic sets only | expand

Checks

Context Check Description
netdev/series_format success Pull request is its own cover letter
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers fail 1 blamed authors not CCed: lucien.xin@gmail.com; 3 maintainers not CCed: coreteam@netfilter.org kadlec@netfilter.org lucien.xin@gmail.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2025-04-04--00-00 (tests: 911)

Commit Message

Pablo Neira Ayuso April 3, 2025, 11:57 a.m. UTC 
From: Lin Ma <linma@zju.edu.cn>

When handling multiple NFTA_TUNNEL_KEY_OPTS_GENEVE attributes, the
parsing logic should place every geneve_opt structure one by one
compactly. Hence, when deciding the next geneve_opt position, the
pointer addition should be in units of char *.

However, the current implementation erroneously does type conversion
before the addition, which will lead to heap out-of-bounds write.

[    6.989857] ==================================================================
[    6.990293] BUG: KASAN: slab-out-of-bounds in nft_tunnel_obj_init+0x977/0xa70
[    6.990725] Write of size 124 at addr ffff888005f18974 by task poc/178
[    6.991162]
[    6.991259] CPU: 0 PID: 178 Comm: poc-oob-write Not tainted 6.1.132 #1
[    6.991655] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
[    6.992281] Call Trace:
[    6.992423]  <TASK>
[    6.992586]  dump_stack_lvl+0x44/0x5c
[    6.992801]  print_report+0x184/0x4be
[    6.993790]  kasan_report+0xc5/0x100
[    6.994252]  kasan_check_range+0xf3/0x1a0
[    6.994486]  memcpy+0x38/0x60
[    6.994692]  nft_tunnel_obj_init+0x977/0xa70
[    6.995677]  nft_obj_init+0x10c/0x1b0
[    6.995891]  nf_tables_newobj+0x585/0x950
[    6.996922]  nfnetlink_rcv_batch+0xdf9/0x1020
[    6.998997]  nfnetlink_rcv+0x1df/0x220
[    6.999537]  netlink_unicast+0x395/0x530
[    7.000771]  netlink_sendmsg+0x3d0/0x6d0
[    7.001462]  __sock_sendmsg+0x99/0xa0
[    7.001707]  ____sys_sendmsg+0x409/0x450
[    7.002391]  ___sys_sendmsg+0xfd/0x170
[    7.003145]  __sys_sendmsg+0xea/0x170
[    7.004359]  do_syscall_64+0x5e/0x90
[    7.005817]  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
[    7.006127] RIP: 0033:0x7ec756d4e407
[    7.006339] Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 faf
[    7.007364] RSP: 002b:00007ffed5d46760 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[    7.007827] RAX: ffffffffffffffda RBX: 00007ec756cc4740 RCX: 00007ec756d4e407
[    7.008223] RDX: 0000000000000000 RSI: 00007ffed5d467f0 RDI: 0000000000000003
[    7.008620] RBP: 00007ffed5d468a0 R08: 0000000000000000 R09: 0000000000000000
[    7.009039] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
[    7.009429] R13: 00007ffed5d478b0 R14: 00007ec756ee5000 R15: 00005cbd4e655cb8

Fix this bug with correct pointer addition and conversion in parse
and dump code.

Fixes: 925d844696d9 ("netfilter: nft_tunnel: add support for geneve opts")
Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nft_tunnel.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/net/netfilter/nft_tunnel.c b/net/netfilter/nft_tunnel.c
index 681301b46aa4..2e40f575aed9 100644
--- a/net/netfilter/nft_tunnel.c
+++ b/net/netfilter/nft_tunnel.c
@@ -341,7 +341,7 @@  static const struct nla_policy nft_tunnel_opts_geneve_policy[NFTA_TUNNEL_KEY_GEN
 static int nft_tunnel_obj_geneve_init(const struct nlattr *attr,
 				      struct nft_tunnel_opts *opts)
 {
-	struct geneve_opt *opt = (struct geneve_opt *)opts->u.data + opts->len;
+	struct geneve_opt *opt = (struct geneve_opt *)(opts->u.data + opts->len);
 	struct nlattr *tb[NFTA_TUNNEL_KEY_GENEVE_MAX + 1];
 	int err, data_len;
 
@@ -625,7 +625,7 @@  static int nft_tunnel_opts_dump(struct sk_buff *skb,
 		if (!inner)
 			goto failure;
 		while (opts->len > offset) {
-			opt = (struct geneve_opt *)opts->u.data + offset;
+			opt = (struct geneve_opt *)(opts->u.data + offset);
 			if (nla_put_be16(skb, NFTA_TUNNEL_KEY_GENEVE_CLASS,
 					 opt->opt_class) ||
 			    nla_put_u8(skb, NFTA_TUNNEL_KEY_GENEVE_TYPE,