5.4-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit 2e8750469242cad8f01f320131fd5a6f540dbb99 ]
syzbot found that sin6_scope_id was not properly initialized, leading to undefined behavior.
Clear sin6_scope_id and sin6_flowinfo.
BUG: KMSAN: uninit-value in __sctp_v6_cmp_addr+0x887/0x8c0 net/sctp/ipv6.c:649 __sctp_v6_cmp_addr+0x887/0x8c0 net/sctp/ipv6.c:649 sctp_inet6_cmp_addr+0x4f2/0x510 net/sctp/ipv6.c:983 sctp_bind_addr_conflict+0x22a/0x3b0 net/sctp/bind_addr.c:390 sctp_get_port_local+0x21eb/0x2440 net/sctp/socket.c:8452 sctp_get_port net/sctp/socket.c:8523 [inline] sctp_listen_start net/sctp/socket.c:8567 [inline] sctp_inet_listen+0x710/0xfd0 net/sctp/socket.c:8636 __sys_listen_socket net/socket.c:1912 [inline] __sys_listen net/socket.c:1927 [inline] __do_sys_listen net/socket.c:1932 [inline] __se_sys_listen net/socket.c:1930 [inline] __x64_sys_listen+0x343/0x4c0 net/socket.c:1930 x64_sys_call+0x271d/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:51 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Local variable addr.i.i created at: sctp_get_port net/sctp/socket.c:8515 [inline] sctp_listen_start net/sctp/socket.c:8567 [inline] sctp_inet_listen+0x650/0xfd0 net/sctp/socket.c:8636 __sys_listen_socket net/socket.c:1912 [inline] __sys_listen net/socket.c:1927 [inline] __do_sys_listen net/socket.c:1932 [inline] __se_sys_listen net/socket.c:1930 [inline] __x64_sys_listen+0x343/0x4c0 net/socket.c:1930
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+e69f06a0f30116c68056@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/68adc0a2.050a0220.37038e.00c4.GAE@google.com/... Signed-off-by: Eric Dumazet edumazet@google.com Cc: Marcelo Ricardo Leitner marcelo.leitner@gmail.com Acked-by: Xin Long lucien.xin@gmail.com Link: https://patch.msgid.link/20250826141314.1802610-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/sctp/ipv6.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c index fae6157e837aa..33981ea102814 100644 --- a/net/sctp/ipv6.c +++ b/net/sctp/ipv6.c @@ -499,7 +499,9 @@ static void sctp_v6_from_sk(union sctp_addr *addr, struct sock *sk) { addr->v6.sin6_family = AF_INET6; addr->v6.sin6_port = 0; + addr->v6.sin6_flowinfo = 0; addr->v6.sin6_addr = sk->sk_v6_rcv_saddr; + addr->v6.sin6_scope_id = 0; }
/* Initialize sk->sk_rcv_saddr from sctp_addr. */