syzbot reported the following uninit-value access issue:
=====================================================
BUG: KMSAN: uninit-value in strscpy+0xc4/0x160
strscpy+0xc4/0x160
bearer_name_validate net/tipc/bearer.c:147 [inline]
tipc_enable_bearer net/tipc/bearer.c:259 [inline]
__tipc_nl_bearer_enable+0x634/0x2220 net/tipc/bearer.c:1043
tipc_nl_bearer_enable+0x3c/0x70 net/tipc/bearer.c:1052
genl_family_rcv_msg_doit net/netlink/genetlink.c:971 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1066
netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1075
netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368
netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910
sock_sendmsg_nosec net/socket.c:730 [inline]
sock_sendmsg net/socket.c:753 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
__sys_sendmsg net/socket.c:2623 [inline]
__do_sys_sendmsg net/socket.c:2632 [inline]
__se_sys_sendmsg net/socket.c:2630 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Uninit was created at:
slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
slab_alloc_node mm/slub.c:3478 [inline]
kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523
kmalloc_reserve+0x148/0x470 net/core/skbuff.c:559
__alloc_skb+0x318/0x740 net/core/skbuff.c:644
alloc_skb include/linux/skbuff.h:1286 [inline]
netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline]
netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885
sock_sendmsg_nosec net/socket.c:730 [inline]
sock_sendmsg net/socket.c:753 [inline]
____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
__sys_sendmsg net/socket.c:2623 [inline]
__do_sys_sendmsg net/socket.c:2632 [inline]
__se_sys_sendmsg net/socket.c:2630 [inline]
__x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Bearer names must be null-terminated strings. If a bearer name which is not
null-terminated is passed through netlink, strcpy() and similar functions
can cause buffer overrun. This causes the above issue.
This patch fixes this issue by returning -EINVAL if a non-null-terminated
bearer name is passed.
Fixes: 0655f6a8635b ("tipc: add bearer disable/enable to new netlink api")
Reported-and-tested-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=9425c47dccbcb4c17d51
Signed-off-by: Shigeru Yoshida <[email protected]>
---
net/tipc/bearer.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index 2cde375477e3..62047d20e14d 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -1025,6 +1025,10 @@ int __tipc_nl_bearer_enable(struct sk_buff *skb, struct genl_info *info)
bearer = nla_data(attrs[TIPC_NLA_BEARER_NAME]);
+ if (bearer[strnlen(bearer,
+ nla_len(attrs[TIPC_NLA_BEARER_NAME]))] != '\0')
+ return -EINVAL;
+
if (attrs[TIPC_NLA_BEARER_DOMAIN])
domain = nla_get_u32(attrs[TIPC_NLA_BEARER_DOMAIN]);
--
2.41.0
On Tue, Sep 26, 2023 at 09:51:20PM +0900, Shigeru Yoshida wrote:
> syzbot reported the following uninit-value access issue:
>
> =====================================================
> BUG: KMSAN: uninit-value in strscpy+0xc4/0x160
> strscpy+0xc4/0x160
> bearer_name_validate net/tipc/bearer.c:147 [inline]
> tipc_enable_bearer net/tipc/bearer.c:259 [inline]
> __tipc_nl_bearer_enable+0x634/0x2220 net/tipc/bearer.c:1043
> tipc_nl_bearer_enable+0x3c/0x70 net/tipc/bearer.c:1052
> genl_family_rcv_msg_doit net/netlink/genetlink.c:971 [inline]
> genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
> genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1066
> netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545
> genl_rcv+0x40/0x60 net/netlink/genetlink.c:1075
> netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
> netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368
> netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910
> sock_sendmsg_nosec net/socket.c:730 [inline]
> sock_sendmsg net/socket.c:753 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
> __sys_sendmsg net/socket.c:2623 [inline]
> __do_sys_sendmsg net/socket.c:2632 [inline]
> __se_sys_sendmsg net/socket.c:2630 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Uninit was created at:
> slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
> slab_alloc_node mm/slub.c:3478 [inline]
> kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523
> kmalloc_reserve+0x148/0x470 net/core/skbuff.c:559
> __alloc_skb+0x318/0x740 net/core/skbuff.c:644
> alloc_skb include/linux/skbuff.h:1286 [inline]
> netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline]
> netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885
> sock_sendmsg_nosec net/socket.c:730 [inline]
> sock_sendmsg net/socket.c:753 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
> __sys_sendmsg net/socket.c:2623 [inline]
> __do_sys_sendmsg net/socket.c:2632 [inline]
> __se_sys_sendmsg net/socket.c:2630 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Bearer names must be null-terminated strings. If a bearer name which is not
> null-terminated is passed through netlink, strcpy() and similar functions
> can cause buffer overrun. This causes the above issue.
>
> This patch fixes this issue by returning -EINVAL if a non-null-terminated
> bearer name is passed.
>
> Fixes: 0655f6a8635b ("tipc: add bearer disable/enable to new netlink api")
> Reported-and-tested-by: [email protected]
> Closes: https://syzkaller.appspot.com/bug?extid=9425c47dccbcb4c17d51
> Signed-off-by: Shigeru Yoshida <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
On Tue, 2023-09-26 at 21:51 +0900, Shigeru Yoshida wrote:
> syzbot reported the following uninit-value access issue:
>
> =====================================================
> BUG: KMSAN: uninit-value in strscpy+0xc4/0x160
> strscpy+0xc4/0x160
> bearer_name_validate net/tipc/bearer.c:147 [inline]
> tipc_enable_bearer net/tipc/bearer.c:259 [inline]
> __tipc_nl_bearer_enable+0x634/0x2220 net/tipc/bearer.c:1043
> tipc_nl_bearer_enable+0x3c/0x70 net/tipc/bearer.c:1052
> genl_family_rcv_msg_doit net/netlink/genetlink.c:971 [inline]
> genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
> genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1066
> netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545
> genl_rcv+0x40/0x60 net/netlink/genetlink.c:1075
> netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
> netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368
> netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910
> sock_sendmsg_nosec net/socket.c:730 [inline]
> sock_sendmsg net/socket.c:753 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
> __sys_sendmsg net/socket.c:2623 [inline]
> __do_sys_sendmsg net/socket.c:2632 [inline]
> __se_sys_sendmsg net/socket.c:2630 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Uninit was created at:
> slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
> slab_alloc_node mm/slub.c:3478 [inline]
> kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523
> kmalloc_reserve+0x148/0x470 net/core/skbuff.c:559
> __alloc_skb+0x318/0x740 net/core/skbuff.c:644
> alloc_skb include/linux/skbuff.h:1286 [inline]
> netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline]
> netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885
> sock_sendmsg_nosec net/socket.c:730 [inline]
> sock_sendmsg net/socket.c:753 [inline]
> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
> __sys_sendmsg net/socket.c:2623 [inline]
> __do_sys_sendmsg net/socket.c:2632 [inline]
> __se_sys_sendmsg net/socket.c:2630 [inline]
> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>
> Bearer names must be null-terminated strings. If a bearer name which is not
> null-terminated is passed through netlink, strcpy() and similar functions
> can cause buffer overrun. This causes the above issue.
>
> This patch fixes this issue by returning -EINVAL if a non-null-terminated
> bearer name is passed.
>
> Fixes: 0655f6a8635b ("tipc: add bearer disable/enable to new netlink api")
> Reported-and-tested-by: [email protected]
> Closes: https://syzkaller.appspot.com/bug?extid=9425c47dccbcb4c17d51
> Signed-off-by: Shigeru Yoshida <[email protected]>
> ---
> net/tipc/bearer.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
> index 2cde375477e3..62047d20e14d 100644
> --- a/net/tipc/bearer.c
> +++ b/net/tipc/bearer.c
> @@ -1025,6 +1025,10 @@ int __tipc_nl_bearer_enable(struct sk_buff *skb, struct genl_info *info)
>
> bearer = nla_data(attrs[TIPC_NLA_BEARER_NAME]);
>
> + if (bearer[strnlen(bearer,
> + nla_len(attrs[TIPC_NLA_BEARER_NAME]))] != '\0')
if 'bearer' is not NULL terminated, the above will access the first
byte after the TIPC_NLA_BEARER_NAME attribute.
I think it would cleaner and safer using nla_strscpy() instead.
Quickly skimming over the tpic code, most TIPC_NLA_BEARER_NAME access
looks unsafe, and possibly a similar fix should be applied in more
places.
Thanks,
Paolo
On Tue, 03 Oct 2023 10:52:50 +0200, Paolo Abeni wrote:
> On Tue, 2023-09-26 at 21:51 +0900, Shigeru Yoshida wrote:
>> syzbot reported the following uninit-value access issue:
>>
>> =====================================================
>> BUG: KMSAN: uninit-value in strscpy+0xc4/0x160
>> strscpy+0xc4/0x160
>> bearer_name_validate net/tipc/bearer.c:147 [inline]
>> tipc_enable_bearer net/tipc/bearer.c:259 [inline]
>> __tipc_nl_bearer_enable+0x634/0x2220 net/tipc/bearer.c:1043
>> tipc_nl_bearer_enable+0x3c/0x70 net/tipc/bearer.c:1052
>> genl_family_rcv_msg_doit net/netlink/genetlink.c:971 [inline]
>> genl_family_rcv_msg net/netlink/genetlink.c:1051 [inline]
>> genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1066
>> netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545
>> genl_rcv+0x40/0x60 net/netlink/genetlink.c:1075
>> netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline]
>> netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368
>> netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910
>> sock_sendmsg_nosec net/socket.c:730 [inline]
>> sock_sendmsg net/socket.c:753 [inline]
>> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
>> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
>> __sys_sendmsg net/socket.c:2623 [inline]
>> __do_sys_sendmsg net/socket.c:2632 [inline]
>> __se_sys_sendmsg net/socket.c:2630 [inline]
>> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>
>> Uninit was created at:
>> slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767
>> slab_alloc_node mm/slub.c:3478 [inline]
>> kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523
>> kmalloc_reserve+0x148/0x470 net/core/skbuff.c:559
>> __alloc_skb+0x318/0x740 net/core/skbuff.c:644
>> alloc_skb include/linux/skbuff.h:1286 [inline]
>> netlink_alloc_large_skb net/netlink/af_netlink.c:1214 [inline]
>> netlink_sendmsg+0xb34/0x13d0 net/netlink/af_netlink.c:1885
>> sock_sendmsg_nosec net/socket.c:730 [inline]
>> sock_sendmsg net/socket.c:753 [inline]
>> ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2540
>> ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2594
>> __sys_sendmsg net/socket.c:2623 [inline]
>> __do_sys_sendmsg net/socket.c:2632 [inline]
>> __se_sys_sendmsg net/socket.c:2630 [inline]
>> __x64_sys_sendmsg+0x307/0x490 net/socket.c:2630
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>>
>> Bearer names must be null-terminated strings. If a bearer name which is not
>> null-terminated is passed through netlink, strcpy() and similar functions
>> can cause buffer overrun. This causes the above issue.
>>
>> This patch fixes this issue by returning -EINVAL if a non-null-terminated
>> bearer name is passed.
>>
>> Fixes: 0655f6a8635b ("tipc: add bearer disable/enable to new netlink api")
>> Reported-and-tested-by: [email protected]
>> Closes: https://syzkaller.appspot.com/bug?extid=9425c47dccbcb4c17d51
>> Signed-off-by: Shigeru Yoshida <[email protected]>
>> ---
>> net/tipc/bearer.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
>> index 2cde375477e3..62047d20e14d 100644
>> --- a/net/tipc/bearer.c
>> +++ b/net/tipc/bearer.c
>> @@ -1025,6 +1025,10 @@ int __tipc_nl_bearer_enable(struct sk_buff *skb, struct genl_info *info)
>>
>> bearer = nla_data(attrs[TIPC_NLA_BEARER_NAME]);
>>
>> + if (bearer[strnlen(bearer,
>> + nla_len(attrs[TIPC_NLA_BEARER_NAME]))] != '\0')
>
> if 'bearer' is not NULL terminated, the above will access the first
> byte after the TIPC_NLA_BEARER_NAME attribute.
>
> I think it would cleaner and safer using nla_strscpy() instead.
Thank you so much for your comment. I didn't notice the existence of
nla_strscpy().
> Quickly skimming over the tpic code, most TIPC_NLA_BEARER_NAME access
> looks unsafe, and possibly a similar fix should be applied in more
> places.
I've checked the usage of TIPC_NLA_BEARER_NAME accesses. These might
cause the same issue, so the same fix should be needed, as you say.
I'll send a v2 patch.
Thanks,
Shigeru
>
> Thanks,
>
> Paolo
>