Am 09.02.23 um 16:36 schrieb Petr Štetiar:
Server can crash on systems using musl libc when client with comma in commonName tries to connect:ifconfig_pool_read(), in='VPN Client, abc,192.168.1.2,' RESOLVE: Cannot parse IP address: abc: (Name does not resolve) as this leads to NULL pointer dereference in freeaddrinfo(): Program received signal SIGSEGV, Segmentation fault. 0x00007ffff7fbf81a in freeaddrinfo (p=0x0) at src/network/freeaddrinfo.c:10 (gdb) bt #0 0x00007ffff7fbf81a in freeaddrinfo (p=0x0) at src/network/freeaddrinfo.c:10 #1 0x00000000004389ec in get_addr_generic (af=af@entry=2, flags=flags@entry=4, hostname=hostname@entry=0x7ffff7ee2988 " abc", network=network@entry=0x7fffffffcb7c, netbits=netbits@entry=0x0, resolve_retry_seconds=resolve_retry_seconds@entry=0, signal_received=0x0, msglevel=64) at openvpn-2.5.7/src/openvpn/socket.c:186 #2 0x0000000000438a2d in getaddr (flags=flags@entry=4, hostname=hostname@entry=0x7ffff7ee2988 " abc", resolve_retry_seconds=resolve_retry_seconds@entry=0, succeeded=succeeded@entry=0x7fffffffcba7, signal_received=signal_received@entry=0x0) at openvpn-2.5.7/src/openvpn/socket.c:202 #3 0x0000000000430ae5 in ifconfig_pool_read (persist=0x7ffff7ee4510, pool=0x7ffff7edd450) at openvpn-2.5.7/src/openvpn/pool.c:661 So fix it by checking if `struct addrinfo*` pointer is valid before passing it down to freeaddrinfo().
I am bit surprised that freeadrinfo does not follow the usual semantics of calling freesomething on a nullptr is a noop.
If this is really the case would should add similar code (with comments that freeaddrinfo is special here) also in gc_freeaddrinfo_callback and the other places that call it without checking for ai to be valid.
Arne _______________________________________________ Openvpn-devel mailing list Openvpn-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openvpn-devel
