| Message ID | 20220601084803.1833344-1-wangyufen@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v4] ipv6: Fix signed integer overflow in __ip6_append_data | expand |
On Wed, 2022-06-01 at 16:48 +0800, Wang Yufen wrote: > Resurrect ubsan overflow checks and ubsan report this warning, > fix it by change the variable [length] type to size_t. > > UBSAN: signed-integer-overflow in net/ipv6/ip6_output.c:1489:19 > 2147479552 + 8567 cannot be represented in type 'int' > CPU: 0 PID: 253 Comm: err Not tainted 5.16.0+ #1 > Hardware name: linux,dummy-virt (DT) > Call trace: > dump_backtrace+0x214/0x230 > show_stack+0x30/0x78 > dump_stack_lvl+0xf8/0x118 > dump_stack+0x18/0x30 > ubsan_epilogue+0x18/0x60 > handle_overflow+0xd0/0xf0 > __ubsan_handle_add_overflow+0x34/0x44 > __ip6_append_data.isra.48+0x1598/0x1688 > ip6_append_data+0x128/0x260 > udpv6_sendmsg+0x680/0xdd0 > inet6_sendmsg+0x54/0x90 > sock_sendmsg+0x70/0x88 > ____sys_sendmsg+0xe8/0x368 > ___sys_sendmsg+0x98/0xe0 > __sys_sendmmsg+0xf4/0x3b8 > __arm64_sys_sendmmsg+0x34/0x48 > invoke_syscall+0x64/0x160 > el0_svc_common.constprop.4+0x124/0x300 > do_el0_svc+0x44/0xc8 > el0_svc+0x3c/0x1e8 > el0t_64_sync_handler+0x88/0xb0 > el0t_64_sync+0x16c/0x170 > > Changes since v1: > -Change the variable [length] type to unsigned, as Eric Dumazet suggested. > Changes since v2: > -Don't change exthdrlen type in ip6_make_skb, as Paolo Abeni suggested. > Changes since v3: > -Don't change ulen type in udpv6_sendmsg and l2tp_ip6_sendmsg, as > Jakub Kicinski suggested. I'm sorry for the multiple incremental feedback on this patch. It's somewhat tricky. AFAICS Jakub mentioned only udpv6_sendmsg(). In l2tp_ip6_sendmsg() we can have an overflow: int transhdrlen = 4; /* zero session-id */ int ulen = len + transhdrlen; when len >= INT_MAX - 4. That will be harmless, but I guess it could still trigger a noisy UBSAN splat. Paolo
On Thu, 02 Jun 2022 12:38:10 +0200 Paolo Abeni wrote: > I'm sorry for the multiple incremental feedback on this patch. It's > somewhat tricky. > > AFAICS Jakub mentioned only udpv6_sendmsg(). In l2tp_ip6_sendmsg() we > can have an overflow: > > int transhdrlen = 4; /* zero session-id */ > int ulen = len + transhdrlen; > > when len >= INT_MAX - 4. That will be harmless, but I guess it could > still trigger a noisy UBSAN splat. Good point, I wonder if that's a separate issue. Should we follow what UDP does and subtract the transhdr from the max? My gut feeling is that stricter checks are cleaner than just bumping variable sizes. diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c index c6ff8bf9b55f..9dbd801ddb98 100644 --- a/net/l2tp/l2tp_ip6.c +++ b/net/l2tp/l2tp_ip6.c @@ -504,14 +504,15 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) struct ipcm6_cookie ipc6; int addr_len = msg->msg_namelen; int transhdrlen = 4; /* zero session-id */ - int ulen = len + transhdrlen; + int ulen; int err; /* Rough check on arithmetic overflow, * better check is made in ip6_append_data(). */ - if (len > INT_MAX) + if (len > INT_MAX - transhdrlen) return -EMSGSIZE; + ulen = len + transhdrlen; /* Mirror BSD error message compatibility */ if (msg->msg_flags & MSG_OOB)
On Thu, 2022-06-02 at 09:02 -0700, Jakub Kicinski wrote: > On Thu, 02 Jun 2022 12:38:10 +0200 Paolo Abeni wrote: > > I'm sorry for the multiple incremental feedback on this patch. It's > > somewhat tricky. > > > > AFAICS Jakub mentioned only udpv6_sendmsg(). In l2tp_ip6_sendmsg() we > > can have an overflow: > > > > int transhdrlen = 4; /* zero session-id */ > > int ulen = len + transhdrlen; > > > > when len >= INT_MAX - 4. That will be harmless, but I guess it could > > still trigger a noisy UBSAN splat. > > Good point, I wonder if that's a separate issue. Should we > follow what UDP does and subtract the transhdr from the max? > My gut feeling is that stricter checks are cleaner than just > bumping variable sizes. > > diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c > index c6ff8bf9b55f..9dbd801ddb98 100644 > --- a/net/l2tp/l2tp_ip6.c > +++ b/net/l2tp/l2tp_ip6.c > @@ -504,14 +504,15 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) > struct ipcm6_cookie ipc6; > int addr_len = msg->msg_namelen; > int transhdrlen = 4; /* zero session-id */ > - int ulen = len + transhdrlen; > + int ulen; > int err; > > /* Rough check on arithmetic overflow, > * better check is made in ip6_append_data(). > */ > - if (len > INT_MAX) > + if (len > INT_MAX - transhdrlen) > return -EMSGSIZE; > + ulen = len + transhdrlen; > > /* Mirror BSD error message compatibility */ > if (msg->msg_flags & MSG_OOB) > LGTM. Imho this can even land in a separated patch (whatever is easier) Thanks! Paolo
在 2022/6/3 16:58, Paolo Abeni 写道: > On Thu, 2022-06-02 at 09:02 -0700, Jakub Kicinski wrote: >> On Thu, 02 Jun 2022 12:38:10 +0200 Paolo Abeni wrote: >>> I'm sorry for the multiple incremental feedback on this patch. It's >>> somewhat tricky. >>> >>> AFAICS Jakub mentioned only udpv6_sendmsg(). In l2tp_ip6_sendmsg() we >>> can have an overflow: >>> >>> int transhdrlen = 4; /* zero session-id */ >>> int ulen = len + transhdrlen; >>> >>> when len >= INT_MAX - 4. That will be harmless, but I guess it could >>> still trigger a noisy UBSAN splat. >> Good point, I wonder if that's a separate issue. Should we >> follow what UDP does and subtract the transhdr from the max? >> My gut feeling is that stricter checks are cleaner than just >> bumping variable sizes. >> >> diff --git a/net/l2tp/l2tp_ip6.c b/net/l2tp/l2tp_ip6.c >> index c6ff8bf9b55f..9dbd801ddb98 100644 >> --- a/net/l2tp/l2tp_ip6.c >> +++ b/net/l2tp/l2tp_ip6.c >> @@ -504,14 +504,15 @@ static int l2tp_ip6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) >> struct ipcm6_cookie ipc6; >> int addr_len = msg->msg_namelen; >> int transhdrlen = 4; /* zero session-id */ >> - int ulen = len + transhdrlen; >> + int ulen; >> int err; >> >> /* Rough check on arithmetic overflow, >> * better check is made in ip6_append_data(). >> */ >> - if (len > INT_MAX) >> + if (len > INT_MAX - transhdrlen) >> return -EMSGSIZE; >> + ulen = len + transhdrlen; >> >> /* Mirror BSD error message compatibility */ >> if (msg->msg_flags & MSG_OOB) >> > LGTM. Imho this can even land in a separated patch (whatever is easier) Thanks for all the feedback. So, Jakub will send a new patch to fix the l2tp_ip6_sendmsg issue? Thanks.
On Mon, 6 Jun 2022 10:03:27 +0800 wangyufen wrote: > > LGTM. Imho this can even land in a separated patch (whatever is easier) > > Thanks for all the feedback. > So, Jakub will send a new patch to fix the l2tp_ip6_sendmsg issue? That was just a suggestion, if possible I'd prefer if you double checked the analysis, tested that or similar code, wrote a commit message etc. and sent it.
在 2022/6/6 22:24, Jakub Kicinski 写道: > On Mon, 6 Jun 2022 10:03:27 +0800 wangyufen wrote: >>> LGTM. Imho this can even land in a separated patch (whatever is easier) >> Thanks for all the feedback. >> So, Jakub will send a new patch to fix the l2tp_ip6_sendmsg issue? > That was just a suggestion, if possible I'd prefer if you double > checked the analysis, tested that or similar code, wrote a commit > message etc. and sent it. > . OK, thanks. will send in v5.
diff --git a/include/net/ipv6.h b/include/net/ipv6.h index 5b38bf1a586b..de9dcc5652c4 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -1063,7 +1063,7 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr); int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), - void *from, int length, int transhdrlen, + void *from, size_t length, int transhdrlen, struct ipcm6_cookie *ipc6, struct flowi6 *fl6, struct rt6_info *rt, unsigned int flags); @@ -1079,7 +1079,7 @@ struct sk_buff *__ip6_make_skb(struct sock *sk, struct sk_buff_head *queue, struct sk_buff *ip6_make_skb(struct sock *sk, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), - void *from, int length, int transhdrlen, + void *from, size_t length, int transhdrlen, struct ipcm6_cookie *ipc6, struct rt6_info *rt, unsigned int flags, struct inet_cork_full *cork); diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 4081b12a01ff..77e3f5970ce4 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1450,7 +1450,7 @@ static int __ip6_append_data(struct sock *sk, struct page_frag *pfrag, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), - void *from, int length, int transhdrlen, + void *from, size_t length, int transhdrlen, unsigned int flags, struct ipcm6_cookie *ipc6) { struct sk_buff *skb, *skb_prev = NULL; @@ -1798,7 +1798,7 @@ static int __ip6_append_data(struct sock *sk, int ip6_append_data(struct sock *sk, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), - void *from, int length, int transhdrlen, + void *from, size_t length, int transhdrlen, struct ipcm6_cookie *ipc6, struct flowi6 *fl6, struct rt6_info *rt, unsigned int flags) { @@ -1995,7 +1995,7 @@ EXPORT_SYMBOL_GPL(ip6_flush_pending_frames); struct sk_buff *ip6_make_skb(struct sock *sk, int getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb), - void *from, int length, int transhdrlen, + void *from, size_t length, int transhdrlen, struct ipcm6_cookie *ipc6, struct rt6_info *rt, unsigned int flags, struct inet_cork_full *cork) {
Resurrect ubsan overflow checks and ubsan report this warning, fix it by change the variable [length] type to size_t. UBSAN: signed-integer-overflow in net/ipv6/ip6_output.c:1489:19 2147479552 + 8567 cannot be represented in type 'int' CPU: 0 PID: 253 Comm: err Not tainted 5.16.0+ #1 Hardware name: linux,dummy-virt (DT) Call trace: dump_backtrace+0x214/0x230 show_stack+0x30/0x78 dump_stack_lvl+0xf8/0x118 dump_stack+0x18/0x30 ubsan_epilogue+0x18/0x60 handle_overflow+0xd0/0xf0 __ubsan_handle_add_overflow+0x34/0x44 __ip6_append_data.isra.48+0x1598/0x1688 ip6_append_data+0x128/0x260 udpv6_sendmsg+0x680/0xdd0 inet6_sendmsg+0x54/0x90 sock_sendmsg+0x70/0x88 ____sys_sendmsg+0xe8/0x368 ___sys_sendmsg+0x98/0xe0 __sys_sendmmsg+0xf4/0x3b8 __arm64_sys_sendmmsg+0x34/0x48 invoke_syscall+0x64/0x160 el0_svc_common.constprop.4+0x124/0x300 do_el0_svc+0x44/0xc8 el0_svc+0x3c/0x1e8 el0t_64_sync_handler+0x88/0xb0 el0t_64_sync+0x16c/0x170 Changes since v1: -Change the variable [length] type to unsigned, as Eric Dumazet suggested. Changes since v2: -Don't change exthdrlen type in ip6_make_skb, as Paolo Abeni suggested. Changes since v3: -Don't change ulen type in udpv6_sendmsg and l2tp_ip6_sendmsg, as Jakub Kicinski suggested. Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Wang Yufen <wangyufen@huawei.com> --- include/net/ipv6.h | 4 ++-- net/ipv6/ip6_output.c | 6 +++--- 2 files changed, 5 insertions(+), 5 deletions(-)