diff mbox series

[net,5/6] netfilter: tproxy: bail out if IP has been disabled on the device

Message ID 20240528225519.1155786-6-pablo@netfilter.org (mailing list archive)
State Accepted
Commit 21a673bddc8fd4873c370caf9ae70ffc6d47e8d3
Delegated to: Netdev Maintainers
Headers show
Series [net,1/6] netfilter: nfnetlink_queue: acquire rcu_read_lock() in instance_destroy_rcu() | 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 fail Errors and warnings before: 45 this patch: 45
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 2 maintainers not CCed: coreteam@netfilter.org dsahern@kernel.org
netdev/build_clang fail Errors and warnings before: 36 this patch: 36
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 fail Errors and warnings before: 45 this patch: 45
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
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

Commit Message

Pablo Neira Ayuso May 28, 2024, 10:55 p.m. UTC 
From: Florian Westphal <fw@strlen.de>

syzbot reports:
general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]
[..]
RIP: 0010:nf_tproxy_laddr4+0xb7/0x340 net/ipv4/netfilter/nf_tproxy_ipv4.c:62
Call Trace:
 nft_tproxy_eval_v4 net/netfilter/nft_tproxy.c:56 [inline]
 nft_tproxy_eval+0xa9a/0x1a00 net/netfilter/nft_tproxy.c:168

__in_dev_get_rcu() can return NULL, so check for this.

Reported-and-tested-by: syzbot+b94a6818504ea90d7661@syzkaller.appspotmail.com
Fixes: cc6eb4338569 ("tproxy: use the interface primary IP address as a default value for --on-ip")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/ipv4/netfilter/nf_tproxy_ipv4.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/net/ipv4/netfilter/nf_tproxy_ipv4.c b/net/ipv4/netfilter/nf_tproxy_ipv4.c
index 69e331799604..73e66a088e25 100644
--- a/net/ipv4/netfilter/nf_tproxy_ipv4.c
+++ b/net/ipv4/netfilter/nf_tproxy_ipv4.c
@@ -58,6 +58,8 @@  __be32 nf_tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
 
 	laddr = 0;
 	indev = __in_dev_get_rcu(skb->dev);
+	if (!indev)
+		return daddr;
 
 	in_dev_for_each_ifa_rcu(ifa, indev) {
 		if (ifa->ifa_flags & IFA_F_SECONDARY)