/* Copyright (C) 1997-2022 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #include #include #include #include #include #include #include #include #include #include #include "nsswitch.h" #ifdef USE_NSCD # include #endif int __nss_hostname_digits_dots (const char *name, struct hostent *resbuf, char **buffer, size_t *buffer_size, size_t buflen, struct hostent **result, enum nss_status *status, int af, int *h_errnop) { /* We have to test for the use of IPv6 which can only be done by examining `_res'. */ struct resolv_context *ctx = __resolv_context_get (); if (ctx == NULL) { if (h_errnop) *h_errnop = NETDB_INTERNAL; if (buffer_size == NULL) *status = NSS_STATUS_TRYAGAIN; else *result = NULL; return -1; } int ret = __nss_hostname_digits_dots_context (ctx, name, resbuf, buffer, buffer_size, buflen, result, status, af, h_errnop); __resolv_context_put (ctx); return ret; } int __nss_hostname_digits_dots_context (struct resolv_context *ctx, const char *name, struct hostent *resbuf, char **buffer, size_t *buffer_size, size_t buflen, struct hostent **result, enum nss_status *status, int af, int *h_errnop) { int save; /* * disallow names consisting only of digits/dots, unless * they end in a dot. */ if (isdigit (name[0]) || isxdigit (name[0]) || name[0] == ':') { const char *cp; char *hostname; typedef unsigned char host_addr_t[16]; host_addr_t *host_addr; typedef char *host_addr_list_t[2]; host_addr_list_t *h_addr_ptrs; char **h_alias_ptr; size_t size_needed; int addr_size; switch (af) { case AF_INET: addr_size = INADDRSZ; break; case AF_INET6: addr_size = IN6ADDRSZ; break; default: af = res_use_inet6 () ? AF_INET6 : AF_INET; addr_size = af == AF_INET6 ? IN6ADDRSZ : INADDRSZ; break; } size_needed = (sizeof (*host_addr) + sizeof (*h_addr_ptrs) + sizeof (*h_alias_ptr) + strlen (name) + 1); if (buffer_size == NULL) { if (buflen < size_needed) { *status = NSS_STATUS_TRYAGAIN; if (h_errnop != NULL) *h_errnop = NETDB_INTERNAL; __set_errno (ERANGE); goto done; } } else if (buffer_size != NULL && *buffer_size < size_needed) { char *new_buf; *buffer_size = size_needed; new_buf = (char *) realloc (*buffer, *buffer_size); if (new_buf == NULL) { save = errno; free (*buffer); *buffer = NULL; *buffer_size = 0; __set_errno (save); if (h_errnop != NULL) *h_errnop = NETDB_INTERNAL; *result = NULL; goto done; } *buffer = new_buf; } memset (*buffer, '\0', size_needed); host_addr = (host_addr_t *) *buffer; h_addr_ptrs = (host_addr_list_t *) ((char *) host_addr + sizeof (*host_addr)); h_alias_ptr = (char **) ((char *) h_addr_ptrs + sizeof (*h_addr_ptrs)); hostname = (char *) h_alias_ptr + sizeof (*h_alias_ptr); if (isdigit (name[0])) { for (cp = name;; ++cp) { if (*cp == '\0') { int ok; if (*--cp == '.') break; /* All-numeric, no dot at the end. Fake up a hostent as if we'd actually done a lookup. What if someone types 255.255.255.255? The test below will succeed spuriously... ??? */ if (af == AF_INET) ok = __inet_aton_exact (name, (struct in_addr *) host_addr); else { assert (af == AF_INET6); ok = inet_pton (af, name, host_addr) > 0; } if (! ok) { *h_errnop = HOST_NOT_FOUND; if (buffer_size == NULL) *status = NSS_STATUS_NOTFOUND; else *result = NULL; goto done; } resbuf->h_name = strcpy (hostname, name); h_alias_ptr[0] = NULL; resbuf->h_aliases = h_alias_ptr; (*h_addr_ptrs)[0] = (char *) host_addr; (*h_addr_ptrs)[1] = NULL; resbuf->h_addr_list = *h_addr_ptrs; if (af == AF_INET && res_use_inet6 ()) { /* We need to change the IP v4 address into the IP v6 address. */ char tmp[INADDRSZ]; char *p = (char *) host_addr; int i; /* Save a copy of the IP v4 address. */ memcpy (tmp, host_addr, INADDRSZ); /* Mark this ipv6 addr as a mapped ipv4. */ for (i = 0; i < 10; i++) *p++ = 0x00; *p++ = 0xff; *p++ = 0xff; /* Copy the IP v4 address. */ memcpy (p, tmp, INADDRSZ); resbuf->h_addrtype = AF_INET6; resbuf->h_length = IN6ADDRSZ; } else { resbuf->h_addrtype = af; resbuf->h_length = addr_size; } if (h_errnop != NULL) *h_errnop = NETDB_SUCCESS; if (buffer_size == NULL) *status = NSS_STATUS_SUCCESS; else *result = resbuf; goto done; } if (!isdigit (*cp) && *cp != '.') break; } } if ((isxdigit (name[0]) && strchr (name, ':') != NULL) || name[0] == ':') { switch (af) { default: af = res_use_inet6 () ? AF_INET6 : AF_INET; if (af == AF_INET6) { addr_size = IN6ADDRSZ; break; } /* FALLTHROUGH */ case AF_INET: /* This is not possible. We cannot represent an IPv6 address in an `struct in_addr' variable. */ *h_errnop = HOST_NOT_FOUND; if (buffer_size == NULL) *status = NSS_STATUS_NOTFOUND; else *result = NULL; goto done; case AF_INET6: addr_size = IN6ADDRSZ; break; } for (cp = name;; ++cp) { if (!*cp) { if (*--cp == '.') break; /* All-IPv6-legal, no dot at the end. Fake up a hostent as if we'd actually done a lookup. */ if (inet_pton (AF_INET6, name, host_addr) <= 0) { *h_errnop = HOST_NOT_FOUND; if (buffer_size == NULL) *status = NSS_STATUS_NOTFOUND; else *result = NULL; goto done; } resbuf->h_name = strcpy (hostname, name); h_alias_ptr[0] = NULL; resbuf->h_aliases = h_alias_ptr; (*h_addr_ptrs)[0] = (char *) host_addr; (*h_addr_ptrs)[1] = (char *) 0; resbuf->h_addr_list = *h_addr_ptrs; resbuf->h_addrtype = AF_INET6; resbuf->h_length = addr_size; *h_errnop = NETDB_SUCCESS; if (buffer_size == NULL) *status = NSS_STATUS_SUCCESS; else *result = resbuf; goto done; } if (!isxdigit (*cp) && *cp != ':' && *cp != '.') break; } } } return 0; done: return 1; } libc_hidden_def (__nss_hostname_digits_dots)