From: Kuniyuki Iwashima <kuniyu@amazon.com>
To: "David S. Miller" <davem@davemloft.net>,
David Ahern <dsahern@kernel.org>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>,
Kuniyuki Iwashima <kuniyu@amazon.com>,
Kuniyuki Iwashima <kuni1840@gmail.com>, <netdev@vger.kernel.org>,
syzkaller <syzkaller@googlegroups.com>,
Yi Lai <yi1.lai@linux.intel.com>
Subject: [PATCH v2 net-next] ipv6: Restore fib6_config validation for SIOCADDRT.
Date: Wed, 30 Apr 2025 17:53:29 -0700 [thread overview]
Message-ID: <20250501005335.53683-1-kuniyu@amazon.com> (raw)
syzkaller reported out-of-bounds read in ipv6_addr_prefix(),
where the prefix length was over 128.
The cited commit accidentally removed some fib6_config
validation from the ioctl path.
Let's restore the validation.
[0]:
BUG: KASAN: slab-out-of-bounds in ip6_route_info_create (./include/net/ipv6.h:616 net/ipv6/route.c:3814)
Read of size 1 at addr ff11000138020ad4 by task repro/261
CPU: 3 UID: 0 PID: 261 Comm: repro Not tainted 6.15.0-rc3-00614-g0d15a26b247d #87 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:123)
print_report (mm/kasan/report.c:409 mm/kasan/report.c:521)
kasan_report (mm/kasan/report.c:636)
ip6_route_info_create (./include/net/ipv6.h:616 net/ipv6/route.c:3814)
ip6_route_add (net/ipv6/route.c:3902)
ipv6_route_ioctl (net/ipv6/route.c:4523)
inet6_ioctl (net/ipv6/af_inet6.c:577)
sock_do_ioctl (net/socket.c:1190)
sock_ioctl (net/socket.c:1314)
__x64_sys_ioctl (fs/ioctl.c:51 fs/ioctl.c:906 fs/ioctl.c:892 fs/ioctl.c:892)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
RIP: 0033:0x7f518fb2de5d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48
RSP: 002b:00007fff14f38d18 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f518fb2de5d
RDX: 00000000200015c0 RSI: 000000000000890b RDI: 0000000000000003
RBP: 00007fff14f38d30 R08: 0000000000000800 R09: 0000000000000800
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff14f38e48
R13: 0000000000401136 R14: 0000000000403df0 R15: 00007f518fd3c000
</TASK>
Fixes: fa76c1674f2e ("ipv6: Move some validation from ip6_route_info_create() to rtm_to_fib6_config().")
Reported-by: syzkaller <syzkaller@googlegroups.com>
Reported-by: Yi Lai <yi1.lai@linux.intel.com>
Closes: https://lore.kernel.org/netdev/aBAcKDEFoN%2FLntBF@ly-workstation/
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
---
v2:
* Remove extra space in a condition
* Fix build failure
v1: https://lore.kernel.org/netdev/20250429014624.61938-1-kuniyu@amazon.com/
---
net/ipv6/route.c | 97 +++++++++++++++++++++++++++---------------------
1 file changed, 55 insertions(+), 42 deletions(-)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index aa6b45bd3515..44300962230b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -4503,6 +4503,53 @@ void rt6_purge_dflt_routers(struct net *net)
rcu_read_unlock();
}
+static int fib6_config_validate(struct fib6_config *cfg,
+ struct netlink_ext_ack *extack)
+{
+ /* RTF_PCPU is an internal flag; can not be set by userspace */
+ if (cfg->fc_flags & RTF_PCPU) {
+ NL_SET_ERR_MSG(extack, "Userspace can not set RTF_PCPU");
+ goto errout;
+ }
+
+ /* RTF_CACHE is an internal flag; can not be set by userspace */
+ if (cfg->fc_flags & RTF_CACHE) {
+ NL_SET_ERR_MSG(extack, "Userspace can not set RTF_CACHE");
+ goto errout;
+ }
+
+ if (cfg->fc_type > RTN_MAX) {
+ NL_SET_ERR_MSG(extack, "Invalid route type");
+ goto errout;
+ }
+
+ if (cfg->fc_dst_len > 128) {
+ NL_SET_ERR_MSG(extack, "Invalid prefix length");
+ goto errout;
+ }
+
+#ifdef CONFIG_IPV6_SUBTREES
+ if (cfg->fc_src_len > 128) {
+ NL_SET_ERR_MSG(extack, "Invalid source address length");
+ goto errout;
+ }
+
+ if (cfg->fc_nh_id && cfg->fc_src_len) {
+ NL_SET_ERR_MSG(extack, "Nexthops can not be used with source routing");
+ goto errout;
+ }
+#else
+ if (cfg->fc_src_len) {
+ NL_SET_ERR_MSG(extack,
+ "Specifying source address requires IPV6_SUBTREES to be enabled");
+ goto errout;
+ }
+#endif
+ return 0;
+errout:
+ return -EINVAL;
+}
+
static void rtmsg_to_fib6_config(struct net *net,
struct in6_rtmsg *rtmsg,
struct fib6_config *cfg)
@@ -4540,6 +4587,10 @@ int ipv6_route_ioctl(struct net *net, unsigned int cmd, struct in6_rtmsg *rtmsg)
switch (cmd) {
case SIOCADDRT:
+ err = fib6_config_validate(&cfg, NULL);
+ if (err)
+ break;
+
/* Only do the default setting of fc_metric in route adding */
if (cfg.fc_metric == 0)
cfg.fc_metric = IP6_RT_PRIO_USER;
@@ -5274,48 +5325,6 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
}
}
- if (newroute) {
- /* RTF_PCPU is an internal flag; can not be set by userspace */
- if (cfg->fc_flags & RTF_PCPU) {
- NL_SET_ERR_MSG(extack, "Userspace can not set RTF_PCPU");
- goto errout;
- }
-
- /* RTF_CACHE is an internal flag; can not be set by userspace */
- if (cfg->fc_flags & RTF_CACHE) {
- NL_SET_ERR_MSG(extack, "Userspace can not set RTF_CACHE");
- goto errout;
- }
-
- if (cfg->fc_type > RTN_MAX) {
- NL_SET_ERR_MSG(extack, "Invalid route type");
- goto errout;
- }
-
- if (cfg->fc_dst_len > 128) {
- NL_SET_ERR_MSG(extack, "Invalid prefix length");
- goto errout;
- }
-
-#ifdef CONFIG_IPV6_SUBTREES
- if (cfg->fc_src_len > 128) {
- NL_SET_ERR_MSG(extack, "Invalid source address length");
- goto errout;
- }
-
- if (cfg->fc_nh_id && cfg->fc_src_len) {
- NL_SET_ERR_MSG(extack, "Nexthops can not be used with source routing");
- goto errout;
- }
-#else
- if (cfg->fc_src_len) {
- NL_SET_ERR_MSG(extack,
- "Specifying source address requires IPV6_SUBTREES to be enabled");
- goto errout;
- }
-#endif
- }
-
err = 0;
errout:
return err;
@@ -5710,6 +5719,10 @@ static int inet6_rtm_newroute(struct sk_buff *skb, struct nlmsghdr *nlh,
if (err < 0)
return err;
+ err = fib6_config_validate(&cfg, extack);
+ if (err)
+ return err;
+
if (cfg.fc_metric == 0)
cfg.fc_metric = IP6_RT_PRIO_USER;
--
2.49.0
next reply other threads:[~2025-05-01 0:53 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-01 0:53 Kuniyuki Iwashima [this message]
2025-05-03 2:00 ` [PATCH v2 net-next] ipv6: Restore fib6_config validation for SIOCADDRT patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250501005335.53683-1-kuniyu@amazon.com \
--to=kuniyu@amazon.com \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=edumazet@google.com \
--cc=horms@kernel.org \
--cc=kuba@kernel.org \
--cc=kuni1840@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=syzkaller@googlegroups.com \
--cc=yi1.lai@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.