X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=userv-utils.git;a=blobdiff_plain;f=ipif%2Fservice.c;h=4137794797185fb69ed80b531726ebbe5466b9f6;hp=18322d4cc71c4c98218aa7b0e6516cdaf7be7afb;hb=f56780b78838933d6ee89f05d639234c5eb5986b;hpb=2c310400b1f8dafa3475bfc0efdba14359603c66 diff --git a/ipif/service.c b/ipif/service.c index 18322d4..4137794 100644 --- a/ipif/service.c +++ b/ipif/service.c @@ -1,35 +1,106 @@ /* - * userv service (or standalone program) - * for per-user IP subranges. + * userv service (or standalone program) for per-user IP subranges. + * + * When invoked appropriately, it creates a point-to-point network + * interface with specified parameters. It arranges for packets sent out + * via that interface by the kernel to appear on its own stdout in SLIP or + * CSLIP encoding, and packets injected into its own stdin to be given to + * the kernel as if received on that interface. Optionally, additional + * routes can be set up to arrange for traffic for other address ranges to + * be routed through the new interface. + * + * This is the service program, which is invoked as root from userv (or may + * be invoked firectly). + * + * Its arguments are supposed to be, in order, as follows: + * + * The first two arguments are usually supplied by the userv + * configuration. See the file `ipif/ipif' in the source tree, which + * is installed in /etc/userv/services.d/ipif by `make install': * - * This is invoked as root, directly from userv. - * Its arguments are supposed to be, in order: * - * Specifies address ranges and gids which own them. - * -- Indicates that the remaining arguments are user-supplied - * and therefore untrusted. + * + * Specifies address ranges and gids which own them. The default + * configuration supplies /etc/userv/ipif-networks, which is then read + * for a list of entries, one per line. + * + * -- + * Serves to separate the user-supplied and therefore untrusted + * arguments from the trusted first argument. + * + * The remaining arguments are supplied by the (untrusted) caller: + * * ,,, + * * As for slattach. Supported protocols are slip, cslip, and - * adaptive. Alternatively, set to `debug' to print debugging - * info. is address of the interface on chiark; - * is the address of the point-to-point peer. + * adaptive. Alternatively, set to `debug' to print debugging info + * and exit. is address of the interface to be created + * on the local system; is the address of the + * point-to-point peer. They must be actual addresses (not + * hostnames). + * * /,/,... - * List of additional routes to add for this interface. - * May be the empty argument, or `-' if this is problematic. * - * is either - * ,/[,] - * indicating that that gid may allocate addresses in - * the relevant subspace ( is ignored) - * or #... - * which is a comment - * or / or ./ or ../ - * which refers to a file which contains lines which - * are each - * or * - * which means that anything is permitted - * - * Should be run from userv with no-disconnect-hup. + * List of additional routes to add for this interface. routes will + * be set up on the local system arranging for packets for those + * networks to be sent via the created interface. must be an + * IPv4 address, and mask must be an integer (dotted-quad masks are + * not supported). If no additional routes are to be set up, use `-' + * or supply an empty argument. + * + * Each item - whether a line file such as + * /etc/userv/ipif-networks, or supplied on the service program + * command line - is one of: + * + * / + * ./ + * ../ + * + * Reads a file which contains lines which are each + * items. + * + * ,[=]/[,] + * + * Indicates that may allocate addresses in the relevant address + * range ( is ignored). must be numeric. To specify a + * single host address, you must specify a mask of /32. If `=' is + * specified then the specific subrange is only allowed for the local + * endpoint address, but not for remote addresses. + * + * * + * Means that anything is to be permitted. This should not appear in + * /etc/userv/ipif-networks, as that would permit any user on the + * system to create any interfaces with any addresses and routes + * attached. It is provided so that root can usefully invoke the ipif + * service program directly (not via userv), without needing to set up + * permissions in /etc/userv/ipif-networks. + * + * #... + * + * Comment. Blank lines are also ignored. + * + * NB: Permission is granted if _any_ config entry matches the request. + * + * The service program should be run from userv with no-disconnect-hup. + */ +/* + * Copyright (C) 1999-2000 Ian Jackson + * + * This is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program 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 + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with userv-utils; if not, write to the Free Software + * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * $Id$ */ #include @@ -49,7 +120,7 @@ #define NARGS 4 #define MAXEXROUTES 5 -#define ATXTLEN 12 +#define ATXTLEN 16 static const unsigned long gidmaxval= (unsigned long)((gid_t)-2); static const char *const protos_ok[]= { "slip", "cslip", "adaptive", 0 }; @@ -258,7 +329,7 @@ static void eat_prefixmask(const char **argp, const char *what, sprintf(whatbuf,"%s length",what); len= eat_number(argp,whatbuf, 0,32, endchars,endchar_r); - mask= (~0UL << (32-len)); + mask= len ? (~0UL << (32-len)) : 0UL; if (prefix & ~mask) badusage("%s prefix %08lx not fully contained in mask %08lx", what,prefix,mask); *prefix_r= prefix; @@ -272,29 +343,31 @@ static int addrnet_isin(unsigned long prefix, unsigned long mask, } -static void permit(unsigned long pprefix, unsigned long pmask) { +static void permit(unsigned long pprefix, unsigned long pmask, int localonly) { int i, any; assert(!(pprefix & ~pmask)); any= 0; - if (!proto) fputs("permits",stdout); + if (!proto) fputs(localonly ? "permits-l" : "permits",stdout); if (addrnet_isin(localaddr,~0UL, pprefix,pmask)) { if (!proto) fputs(" local-addr",stdout); any= localallow= 1; } - if (addrnet_isin(peeraddr,~0UL, pprefix,pmask)) { - if (!proto) fputs(" peer-addr",stdout); - any= peerallow= 1; - } - for (i=0; i