diff options
Diffstat (limited to 'lib/util/getgrouplist.c')
| -rw-r--r-- | lib/util/getgrouplist.c | 529 |
1 files changed, 529 insertions, 0 deletions
diff --git a/lib/util/getgrouplist.c b/lib/util/getgrouplist.c new file mode 100644 index 0000000..b6170c6 --- /dev/null +++ b/lib/util/getgrouplist.c @@ -0,0 +1,529 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 2010, 2011, 2013-2021 + * Todd C. Miller <Todd.Miller@sudo.ws> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* + * This is an open source non-commercial project. Dear PVS-Studio, please check it. + * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com + */ + +#include <config.h> + +#include <stdlib.h> +#include <string.h> +#include <grp.h> +#include <limits.h> +#include <unistd.h> +#ifdef HAVE_NSS_SEARCH +# include <errno.h> +# include <limits.h> +# include <nsswitch.h> +# ifdef HAVE_NSS_DBDEFS_H +# include <nss_dbdefs.h> +# else +# include "compat/nss_dbdefs.h" +# endif +#endif + +#include "sudo_compat.h" +#include "sudo_debug.h" +#include "sudo_util.h" + +#ifndef HAVE_GETGROUPLIST +int +sudo_getgrouplist(const char *name, GETGROUPS_T basegid, GETGROUPS_T *groups, + int *ngroupsp) +{ + return sudo_getgrouplist2(name, basegid, &groups, ngroupsp); +} +#endif /* HAVE_GETGROUPLIST */ + +#if defined(HAVE_GETGROUPLIST) + +#if defined(HAVE_GETGROUPLIST_2) && !HAVE_DECL_GETGROUPLIST_2 +int getgrouplist_2(const char *name, GETGROUPS_T basegid, GETGROUPS_T **groups); +#endif /* HAVE_GETGROUPLIST_2 && !HAVE_DECL_GETGROUPLIST_2 */ + +/* + * Extended getgrouplist(3) using getgrouplist(3) and getgrouplist_2(3) + */ +int +sudo_getgrouplist2_v1(const char *name, GETGROUPS_T basegid, + GETGROUPS_T **groupsp, int *ngroupsp) +{ +#ifdef __APPLE__ + int *groups = (int *)*groupsp; +#else + GETGROUPS_T *groups = *groupsp; +#endif + int ngroups; +#ifndef HAVE_GETGROUPLIST_2 + int grpsize, tries; +#endif + debug_decl(sudo_getgrouplist2, SUDO_DEBUG_UTIL); + + /* For static group vector, just use getgrouplist(3). */ + if (groups != NULL) + debug_return_int(getgrouplist(name, basegid, groups, ngroupsp)); + +#ifdef HAVE_GETGROUPLIST_2 + if ((ngroups = getgrouplist_2(name, basegid, groupsp)) == -1) + debug_return_int(-1); + *ngroupsp = ngroups; + debug_return_int(0); +#else + grpsize = (int)sysconf(_SC_NGROUPS_MAX); + if (grpsize < 0) + grpsize = NGROUPS_MAX; + grpsize++; /* include space for the primary gid */ + /* + * It is possible to belong to more groups in the group database + * than NGROUPS_MAX. + */ + for (tries = 0; tries < 10; tries++) { + free(groups); + groups = reallocarray(NULL, grpsize, sizeof(*groups)); + if (groups == NULL) + debug_return_int(-1); + ngroups = grpsize; + if (getgrouplist(name, basegid, groups, &ngroups) != -1) { + *groupsp = groups; + *ngroupsp = ngroups; + debug_return_int(0); + } + if (ngroups == grpsize) { + /* Failed for some reason other than ngroups too small. */ + break; + } + /* getgrouplist(3) set ngroups to the required length, use it. */ + grpsize = ngroups; + } + free(groups); + debug_return_int(-1); +#endif /* HAVE_GETGROUPLIST_2 */ +} + +#elif defined(HAVE_GETGRSET) + +/* + * Extended getgrouplist(3) using AIX getgrset(3) + */ +int +sudo_getgrouplist2_v1(const char *name, GETGROUPS_T basegid, + GETGROUPS_T **groupsp, int *ngroupsp) +{ + GETGROUPS_T *groups = *groupsp; + char *cp, *last, *grset = NULL; + const char *errstr; + int ngroups = 1; + int grpsize = *ngroupsp; + int ret = -1; + gid_t gid; + debug_decl(sudo_getgrouplist2, SUDO_DEBUG_UTIL); + +#ifdef HAVE_SETAUTHDB + aix_setauthdb((char *) name, NULL); +#endif + if ((grset = getgrset(name)) == NULL) + goto done; + + if (groups == NULL) { + /* Dynamically-sized group vector, count groups and alloc. */ + grpsize = 1; /* reserve one for basegid */ + if (*grset != '\0') { + grpsize++; /* at least one supplementary group */ + for (cp = grset; *cp != '\0'; cp++) { + if (*cp == ',') + grpsize++; + } + } + groups = reallocarray(NULL, grpsize, sizeof(*groups)); + if (groups == NULL) + debug_return_int(-1); + } else { + /* Static group vector. */ + if (grpsize < 1) + debug_return_int(-1); + } + + /* We support BSD semantics where the first element is the base gid */ + groups[0] = basegid; + + for (cp = strtok_r(grset, ",", &last); cp != NULL; cp = strtok_r(NULL, ",", &last)) { + gid = sudo_strtoid(cp, &errstr); + if (errstr == NULL && gid != basegid) { + if (ngroups == grpsize) + goto done; + groups[ngroups++] = gid; + } + } + ret = 0; + +done: + free(grset); +#ifdef HAVE_SETAUTHDB + aix_restoreauthdb(); +#endif + *groupsp = groups; + *ngroupsp = ngroups; + + debug_return_int(ret); +} + +#elif defined(HAVE_NSS_SEARCH) + +#ifndef ALIGNBYTES +# define ALIGNBYTES (sizeof(long) - 1L) +#endif +#ifndef ALIGN +# define ALIGN(p) (((unsigned long)(p) + ALIGNBYTES) & ~ALIGNBYTES) +#endif + +#if defined(HAVE__NSS_INITF_GROUP) || defined(HAVE___NSS_INITF_GROUP) +extern void _nss_initf_group(nss_db_params_t *params); +#else +static void +_nss_initf_group(nss_db_params_t *params) +{ + params->name = NSS_DBNAM_GROUP; + params->default_config = NSS_DEFCONF_GROUP; +} +#endif + +/* + * Convert a groups file string (instr) to a struct group (ent) using + * buf for storage. + */ +static int +str2grp(const char *instr, int inlen, void *ent, char *buf, int buflen) +{ + struct group *grp = ent; + char *cp, *fieldsep = buf; + char **gr_mem, **gr_end; + const char *errstr; + int yp = 0; + id_t id; + debug_decl(str2grp, SUDO_DEBUG_UTIL); + + /* Must at least have space to copy instr -> buf. */ + if (inlen >= buflen) + debug_return_int(NSS_STR_PARSE_ERANGE); + + /* Paranoia: buf and instr should be distinct. */ + if (buf != instr) { + memmove(buf, instr, inlen); + buf[inlen] = '\0'; + } + + if ((fieldsep = strchr(cp = fieldsep, ':')) == NULL) + debug_return_int(NSS_STR_PARSE_PARSE); + *fieldsep++ = '\0'; + grp->gr_name = cp; + + /* Check for YP inclusion/exclusion entries. */ + if (*cp == '+' || *cp == '-') { + /* Only the name is required for YP inclusion/exclusion entries. */ + grp->gr_passwd = (char *)""; + grp->gr_gid = 0; + grp->gr_mem = NULL; + yp = 1; + } + + if ((fieldsep = strchr(cp = fieldsep, ':')) == NULL) + debug_return_int(yp ? NSS_STR_PARSE_SUCCESS : NSS_STR_PARSE_PARSE); + *fieldsep++ = '\0'; + grp->gr_passwd = cp; + + if ((fieldsep = strchr(cp = fieldsep, ':')) == NULL) + debug_return_int(yp ? NSS_STR_PARSE_SUCCESS : NSS_STR_PARSE_PARSE); + *fieldsep++ = '\0'; + id = sudo_strtoid(cp, &errstr); + if (errstr != NULL) { + /* + * A range error is always a fatal error, but ignore garbage + * at the end of YP entries since it has no meaning. + */ + if (errno == ERANGE) + debug_return_int(NSS_STR_PARSE_ERANGE); + debug_return_int(yp ? NSS_STR_PARSE_SUCCESS : NSS_STR_PARSE_PARSE); + } +#ifdef GID_NOBODY + /* Negative gids get mapped to nobody on Solaris. */ + if (*cp == '-' && id != 0) + grp->gr_gid = GID_NOBODY; + else +#endif + grp->gr_gid = (gid_t)id; + + /* Store group members, taking care to use proper alignment. */ + grp->gr_mem = NULL; + if (*fieldsep != '\0') { + grp->gr_mem = gr_mem = (char **)ALIGN(buf + inlen + 1); + gr_end = (char **)((unsigned long)(buf + buflen) & ~ALIGNBYTES) - 1; + for (;;) { + if (gr_mem >= gr_end) + debug_return_int(NSS_STR_PARSE_ERANGE); /* out of space! */ + *gr_mem++ = cp; + if (fieldsep == NULL) + break; + if ((fieldsep = strchr(cp = fieldsep, ',')) != NULL) + *fieldsep++ = '\0'; + } + *gr_mem = NULL; + } + debug_return_int(NSS_STR_PARSE_SUCCESS); +} + +static nss_status_t +process_cstr(const char *instr, int inlen, struct nss_groupsbymem *gbm, + int dynamic) +{ + const char *user = gbm->username; + nss_status_t ret = NSS_NOTFOUND; + nss_XbyY_buf_t *buf; + struct group *grp; + char **gr_mem; + int error, i; + debug_decl(process_cstr, SUDO_DEBUG_UTIL); + + sudo_debug_printf(SUDO_DEBUG_INFO, "%s: parsing %.*s", __func__, + inlen, instr); + + /* Hack to let us check whether the query was handled by nscd or us. */ + if (gbm->force_slow_way != 0) + gbm->force_slow_way = 2; + + buf = _nss_XbyY_buf_alloc(sizeof(struct group), NSS_BUFLEN_GROUP); + if (buf == NULL) + debug_return_int(NSS_UNAVAIL); + + /* Parse groups file string -> struct group. */ + grp = buf->result; + error = (*gbm->str2ent)(instr, inlen, grp, buf->buffer, buf->buflen); + if (error != NSS_STR_PARSE_SUCCESS || grp->gr_mem == NULL) + goto done; + + for (gr_mem = grp->gr_mem; *gr_mem != NULL; gr_mem++) { + if (strcmp(*gr_mem, user) == 0) { + const int numgids = MIN(gbm->numgids, gbm->maxgids); + + /* Append to gid_array unless gr_gid is a dupe. */ + for (i = 0; i < numgids; i++) { + if (gbm->gid_array[i] == grp->gr_gid) + goto done; /* already present */ + } + if (i == gbm->maxgids && dynamic) { + GETGROUPS_T *tmp = reallocarray(gbm->gid_array, gbm->maxgids, + 2 * sizeof(GETGROUPS_T)); + if (tmp == NULL) { + /* Out of memory, just return what we have. */ + dynamic = 0; + } else { + gbm->gid_array = tmp; + gbm->maxgids <<= 1; + } + } + /* Store gid if there is space. */ + if (i < gbm->maxgids) + gbm->gid_array[i] = grp->gr_gid; + /* Always increment numgids so we can detect when out of space. */ + gbm->numgids++; + goto done; + } + } +done: + _nss_XbyY_buf_free(buf); + debug_return_int(ret); +} + +static nss_status_t +process_cstr_static(const char *instr, int inlen, struct nss_groupsbymem *gbm) +{ + return process_cstr(instr, inlen, gbm, 0); +} + +static nss_status_t +process_cstr_dynamic(const char *instr, int inlen, struct nss_groupsbymem *gbm) +{ + return process_cstr(instr, inlen, gbm, 1); +} + +/* + * Extended getgrouplist(3) using nss_search(3) + */ +int +sudo_getgrouplist2_v1(const char *name, GETGROUPS_T basegid, + GETGROUPS_T **groupsp, int *ngroupsp) +{ + struct nss_groupsbymem gbm; + static DEFINE_NSS_DB_ROOT(db_root); + debug_decl(sudo_getgrouplist2, SUDO_DEBUG_UTIL); + + memset(&gbm, 0, sizeof(gbm)); + gbm.username = name; + gbm.gid_array = *groupsp; + gbm.maxgids = *ngroupsp; + gbm.numgids = 1; /* for basegid */ + gbm.force_slow_way = 1; + gbm.str2ent = str2grp; + + if (gbm.gid_array == NULL) { + /* Dynamically-sized group vector. */ + gbm.maxgids = (int)sysconf(_SC_NGROUPS_MAX); + if (gbm.maxgids < 0) + gbm.maxgids = NGROUPS_MAX; + gbm.gid_array = reallocarray(NULL, gbm.maxgids, 4 * sizeof(GETGROUPS_T)); + if (gbm.gid_array == NULL) + debug_return_int(-1); + gbm.maxgids <<= 2; + gbm.process_cstr = process_cstr_dynamic; + } else { + /* Static group vector. */ + if (gbm.maxgids <= 0) + debug_return_int(-1); + gbm.process_cstr = process_cstr_static; + } + + /* We support BSD semantics where the first element is the base gid */ + gbm.gid_array[0] = basegid; + + /* + * Can't use nss_search return value since it may return NSS_UNAVAIL + * when no nsswitch.conf entry (e.g. compat mode). + */ + for (;;) { + GETGROUPS_T *tmp; + + (void)nss_search(&db_root, _nss_initf_group, NSS_DBOP_GROUP_BYMEMBER, + &gbm); + + /* + * If this was a statically-sized group vector or nscd was not used + * we are done. + */ + if (gbm.process_cstr != process_cstr_dynamic || gbm.force_slow_way == 2) + break; + + /* + * If gid_array is full and the query was handled by nscd, there + * may be more data, so double gid_array and try again. + */ + if (gbm.numgids != gbm.maxgids) + break; + + tmp = reallocarray(gbm.gid_array, gbm.maxgids, 2 * sizeof(GETGROUPS_T)); + if (tmp == NULL) { + free(gbm.gid_array); + debug_return_int(-1); + } + gbm.gid_array = tmp; + gbm.maxgids <<= 1; + } + + /* Note: we can only detect a too-small group list if nscd is not used. */ + *groupsp = gbm.gid_array; + if (gbm.numgids <= gbm.maxgids) { + *ngroupsp = gbm.numgids; + debug_return_int(0); + } + *ngroupsp = gbm.maxgids; + debug_return_int(-1); +} + +#else /* !HAVE_GETGROUPLIST && !HAVE_GETGRSET && !HAVE__GETGROUPSBYMEMBER */ + +/* + * Extended getgrouplist(3) using getgrent(3) + */ +int +sudo_getgrouplist2_v1(const char *name, GETGROUPS_T basegid, + GETGROUPS_T **groupsp, int *ngroupsp) +{ + GETGROUPS_T *groups = *groupsp; + int grpsize = *ngroupsp; + int i, ngroups = 1; + int ret = -1; + struct group *grp; + debug_decl(sudo_getgrouplist2, SUDO_DEBUG_UTIL); + + if (groups == NULL) { + /* Dynamically-sized group vector. */ + grpsize = (int)sysconf(_SC_NGROUPS_MAX); + if (grpsize < 0) + grpsize = NGROUPS_MAX; + groups = reallocarray(NULL, grpsize, 4 * sizeof(*groups)); + if (groups == NULL) + debug_return_int(-1); + grpsize <<= 2; + } else { + /* Static group vector. */ + if (grpsize < 1) + debug_return_int(-1); + } + + /* We support BSD semantics where the first element is the base gid */ + groups[0] = basegid; + + setgrent(); + while ((grp = getgrent()) != NULL) { + if (grp->gr_gid == basegid || grp->gr_mem == NULL) + continue; + + for (i = 0; grp->gr_mem[i] != NULL; i++) { + if (strcmp(name, grp->gr_mem[i]) == 0) + break; + } + if (grp->gr_mem[i] == NULL) + continue; /* user not found */ + + /* Only add if it is not the same as an existing gid */ + for (i = 0; i < ngroups; i++) { + if (grp->gr_gid == groups[i]) + break; + } + if (i == ngroups) { + if (ngroups == grpsize) { + GETGROUPS_T *tmp; + + if (*groupsp != NULL) { + /* Static group vector. */ + goto done; + } + tmp = reallocarray(groups, grpsize, 2 * sizeof(*groups)); + if (tmp == NULL) { + free(groups); + groups = NULL; + ngroups = 0; + goto done; + } + groups = tmp; + grpsize <<= 1; + } + groups[ngroups++] = grp->gr_gid; + } + } + ret = 0; + +done: + endgrent(); + *groupsp = groups; + *ngroupsp = ngroups; + + debug_return_int(ret); +} +#endif /* !HAVE_GETGROUPLIST && !HAVE_GETGRSET && !HAVE__GETGROUPSBYMEMBER */ |