[PATCH AUTOSEL 5.18 33/47] ipv6: Fix signed integer overflow in __ip6_append_data

[Sasha Levin <sashal@kernel.org>]

From: Wang Yufen <wangyufen@huawei.com>

[ Upstream commit f93431c86b631bbca5614c66f966bf3ddb3c2803 ]

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>
Link: https://lore.kernel.org/r/20220607120028.845916-1-wangyufen@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/ipv6.h    | 4 ++--
 net/ipv6/ip6_output.c | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 213612f1680c..023435ce1606 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -1019,7 +1019,7 @@ 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);
 
@@ -1035,7 +1035,7 @@ 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 fa63ef2bd99c..87067e0ddaa3 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1428,7 +1428,7 @@ 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;
@@ -1776,7 +1776,7 @@ 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)
 {
@@ -1973,7 +1973,7 @@ 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)
 {
-- 
2.35.1