Hi, Simon
Faced with dnsmasq crash on aarch64 (32bit userspace, arm-buildroot-linux-gnueabi-gcc 5.3.0) with dhcpv6 stateful configured. Unaligned packet’s req_addr is used in lease6_allocate() for struct copy since 2.67test15 (commit 89500e31f199e9ae1eadc86213b911ff44d30d6f). As for other places, seems well-aligned stack-local vars are used. Please refer proposed patch attached and gdb trace: Program received signal SIGBUS, Bus error. 0x0003f990 in lease6_allocate (addrp=0xa55e6, lease_type=32) at lease.c:822 822 lease->addr6 = *addrp; (gdb) bt #0 0x0003f990 in lease6_allocate (addrp=0xa55e6, lease_type=32) at lease.c:822 #1 0x00055fac in update_leases (state=0xfffef8ac, context=0xa7ee8, addr=0xa55e6, lease_time=900, now=14609) at rfc3315.c:1825 #2 0x00055ab4 in add_address (state=0xfffef8ac, context=0xa7ee8, lease_time=900, ia_option=0xa55e2, min_time=0xfffef6d0, addr=0xa55e6, now=14609) at rfc3315.c:1684 #3 0x00053764 in dhcp6_no_relay (state=0xfffef8ac, msg_type=3, inbuff=0xa55a8, sz=128, is_unicast=0, now=14609) at rfc3315.c:938 #4 0x00051744 in dhcp6_maybe_relay (state=0xfffef8ac, inbuff=0xa55a8, sz=128, client_addr=0xfffef9a0, is_unicast=0, now=14609) at rfc3315.c:172 #5 0x000513b8 in dhcp6_reply (context=0xa7ee8, interface=23, iface_name=0xfffef978, fallback=0xfffef9f8, ll_addr=0xfffefa18, ula_addr=0xfffefa28, sz=128, client_addr=0xfffef9a0, now=14609) at rfc3315.c:103 #6 0x0004f4b4 in dhcp6_packet (now=14609) at dhcp6.c:233 #7 0x00038c78 in main (argc=3, argv=0xfffefd34) at dnsmasq.c:1099 Best Regards, Vladislav Grishenko
0001-dhcpv6-fix-unaligned-access-crash-on-aarch64.patch
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