diff options
Diffstat (limited to 'libmisc/find_new_gid.c')
| -rw-r--r-- | libmisc/find_new_gid.c | 483 |
1 files changed, 0 insertions, 483 deletions
diff --git a/libmisc/find_new_gid.c b/libmisc/find_new_gid.c deleted file mode 100644 index 65ab5d0..0000000 --- a/libmisc/find_new_gid.c +++ /dev/null @@ -1,483 +0,0 @@ -/* - * SPDX-FileCopyrightText: 1991 - 1994, Julianne Frances Haugh - * SPDX-FileCopyrightText: 2008 - 2011, Nicolas François - * SPDX-FileCopyrightText: 2014, Red Hat, Inc. - * - * SPDX-License-Identifier: BSD-3-Clause - */ - -#include <config.h> - -#include <assert.h> -#include <stdio.h> -#include <errno.h> - -#include "prototypes.h" -#include "groupio.h" -#include "getdef.h" -#include "shadowlog.h" - -/* - * get_ranges - Get the minimum and maximum ID ranges for the search - * - * This function will return the minimum and maximum ranges for IDs - * - * 0: The function completed successfully - * EINVAL: The provided ranges are impossible (such as maximum < minimum) - * - * preferred_min: The special-case minimum value for a specifically- - * requested ID, which may be lower than the standard min_id - */ -static int get_ranges (bool sys_group, gid_t *min_id, gid_t *max_id, - gid_t *preferred_min) -{ - gid_t gid_def_max = 0; - - if (sys_group) { - /* System groups */ - - /* A requested ID is allowed to be below the autoselect range */ - *preferred_min = (gid_t) 1; - - /* Get the minimum ID range from login.defs or default to 101 */ - *min_id = (gid_t) getdef_ulong ("SYS_GID_MIN", 101UL); - - /* - * If SYS_GID_MAX is unspecified, we should assume it to be one - * less than the GID_MIN (which is reserved for non-system accounts) - */ - gid_def_max = (gid_t) getdef_ulong ("GID_MIN", 1000UL) - 1; - *max_id = (gid_t) getdef_ulong ("SYS_GID_MAX", - (unsigned long) gid_def_max); - - /* Check that the ranges make sense */ - if (*max_id < *min_id) { - (void) fprintf (log_get_logfd(), - _("%s: Invalid configuration: SYS_GID_MIN (%lu), " - "GID_MIN (%lu), SYS_GID_MAX (%lu)\n"), - log_get_progname(), (unsigned long) *min_id, - getdef_ulong ("GID_MIN", 1000UL), - (unsigned long) *max_id); - return EINVAL; - } - /* - * Zero is reserved for root and the allocation algorithm does not - * work right with it. - */ - if (*min_id == 0) { - *min_id = (gid_t) 1; - } - } else { - /* Non-system groups */ - - /* Get the values from login.defs or use reasonable defaults */ - *min_id = (gid_t) getdef_ulong ("GID_MIN", 1000UL); - *max_id = (gid_t) getdef_ulong ("GID_MAX", 60000UL); - - /* - * The preferred minimum should match the standard ID minimum - * for non-system groups. - */ - *preferred_min = *min_id; - - /* Check that the ranges make sense */ - if (*max_id < *min_id) { - (void) fprintf (log_get_logfd(), - _("%s: Invalid configuration: GID_MIN (%lu), " - "GID_MAX (%lu)\n"), - log_get_progname(), (unsigned long) *min_id, - (unsigned long) *max_id); - return EINVAL; - } - } - - return 0; -} - -/* - * check_gid - See if the requested GID is available - * - * On success, return 0 - * If the ID is in use, return EEXIST - * If the ID is outside the range, return ERANGE - * In other cases, return errno from getgrgid() - */ -static int check_gid (const gid_t gid, - const gid_t gid_min, - const gid_t gid_max, - const bool *used_gids) -{ - /* First test that the preferred ID is in the range */ - if (gid < gid_min || gid > gid_max) { - return ERANGE; - } - - /* - * Check whether we already detected this GID - * using the gr_next() loop - */ - if (used_gids != NULL && used_gids[gid]) { - return EEXIST; - } - /* Check if the GID exists according to NSS */ - errno = 0; - if (prefix_getgrgid (gid) != NULL) { - return EEXIST; - } else { - /* getgrgid() was NULL - * we have to ignore errors as temporary - * failures of remote user identity services - * would completely block user/group creation - */ - } - - /* If we've made it here, the GID must be available */ - return 0; -} - -/* - * find_new_gid - Find a new unused GID. - * - * If successful, find_new_gid provides an unused group ID in the - * [GID_MIN:GID_MAX] range. - * This ID should be higher than all the used GID, but if not possible, - * the lowest unused ID in the range will be returned. - * - * Return 0 on success, -1 if no unused GIDs are available. - */ -int find_new_gid (bool sys_group, - gid_t *gid, - /*@null@*/gid_t const *preferred_gid) -{ - bool *used_gids; - const struct group *grp; - gid_t gid_min, gid_max, preferred_min; - gid_t id; - gid_t lowest_found, highest_found; - int result; - int nospam = 0; - - assert(gid != NULL); - - /* - * First, figure out what ID range is appropriate for - * automatic assignment - */ - result = get_ranges (sys_group, &gid_min, &gid_max, &preferred_min); - if (result == EINVAL) { - return -1; - } - - /* Check if the preferred GID is available */ - if (preferred_gid) { - result = check_gid (*preferred_gid, preferred_min, gid_max, NULL); - if (result == 0) { - /* - * Make sure the GID isn't queued for use already - */ - if (gr_locate_gid (*preferred_gid) == NULL) { - *gid = *preferred_gid; - return 0; - } - /* - * gr_locate_gid() found the GID in an as-yet uncommitted - * entry. We'll proceed below and auto-set a GID. - */ - } else if (result == EEXIST || result == ERANGE) { - /* - * Continue on below. At this time, we won't - * treat these two cases differently. - */ - } else { - /* - * An unexpected error occurred. We should report - * this and fail the group creation. - * This differs from the automatic creation - * behavior below, since if a specific GID was - * requested and generated an error, the user is - * more likely to want to stop and address the - * issue. - */ - fprintf (log_get_logfd(), - _("%s: Encountered error attempting to use " - "preferred GID: %s\n"), - log_get_progname(), strerror (result)); - return -1; - } - } - - /* - * Search the entire group file, - * looking for the next unused value. - * - * We first check the local database with gr_rewind/gr_next to find - * all local values that are in use. - * - * We then compare the next free value to all databases (local and - * remote) and iterate until we find a free one. If there are free - * values beyond the lowest (system groups) or highest (non-system - * groups), we will prefer those and avoid potentially reclaiming a - * deleted group (which can be a security issue, since it may grant - * access to files belonging to that former group). - * - * If there are no GIDs available at the end of the search, we will - * have no choice but to iterate through the range looking for gaps. - * - */ - - /* Create an array to hold all of the discovered GIDs */ - used_gids = malloc (sizeof (bool) * (gid_max +1)); - if (NULL == used_gids) { - fprintf (log_get_logfd(), - _("%s: failed to allocate memory: %s\n"), - log_get_progname(), strerror (errno)); - return -1; - } - memset (used_gids, false, sizeof (bool) * (gid_max + 1)); - - /* First look for the lowest and highest value in the local database */ - (void) gr_rewind (); - highest_found = gid_min; - lowest_found = gid_max; - while ((grp = gr_next ()) != NULL) { - /* - * Does this entry have a lower GID than the lowest we've found - * so far? - */ - if ((grp->gr_gid <= lowest_found) && (grp->gr_gid >= gid_min)) { - lowest_found = grp->gr_gid - 1; - } - - /* - * Does this entry have a higher GID than the highest we've found - * so far? - */ - if ((grp->gr_gid >= highest_found) && (grp->gr_gid <= gid_max)) { - highest_found = grp->gr_gid + 1; - } - - /* create index of used GIDs */ - if (grp->gr_gid >= gid_min - && grp->gr_gid <= gid_max) { - - used_gids[grp->gr_gid] = true; - } - } - - if (sys_group) { - /* - * For system groups, we want to start from the - * top of the range and work downwards. - */ - - /* - * At the conclusion of the gr_next() search, we will either - * have a presumed-free GID or we will be at GID_MIN - 1. - */ - if (lowest_found < gid_min) { - /* - * In this case, a GID is in use at GID_MIN. - * - * We will reset the search to GID_MAX and proceed down - * through all the GIDs (skipping those we detected with - * used_gids) for a free one. It is a known issue that - * this may result in reusing a previously-deleted GID, - * so administrators should be instructed to use this - * auto-detection with care (and prefer to assign GIDs - * explicitly). - */ - lowest_found = gid_max; - } - - /* Search through all of the IDs in the range */ - for (id = lowest_found; id >= gid_min; id--) { - result = check_gid (id, gid_min, gid_max, used_gids); - if (result == 0) { - /* This GID is available. Return it. */ - *gid = id; - free (used_gids); - return 0; - } else if (result == EEXIST) { - /* This GID is in use, we'll continue to the next */ - } else { - /* - * An unexpected error occurred. - * - * Only report it the first time to avoid spamming - * the logs - * - */ - if (!nospam) { - fprintf (log_get_logfd(), - _("%s: Can't get unique system GID (%s). " - "Suppressing additional messages.\n"), - log_get_progname(), strerror (result)); - SYSLOG ((LOG_ERR, - "Error checking available GIDs: %s", - strerror (result))); - nospam = 1; - } - /* - * We will continue anyway. Hopefully a later GID - * will work properly. - */ - } - } - - /* - * If we get all the way through the loop, try again from GID_MAX, - * unless that was where we previously started. (NOTE: the worst-case - * scenario here is that we will run through (GID_MAX - GID_MIN - 1) - * cycles *again* if we fall into this case with lowest_found as - * GID_MAX - 1, all groups in the range in use and maintained by - * network services such as LDAP.) - */ - if (lowest_found != gid_max) { - for (id = gid_max; id >= gid_min; id--) { - result = check_gid (id, gid_min, gid_max, used_gids); - if (result == 0) { - /* This GID is available. Return it. */ - *gid = id; - free (used_gids); - return 0; - } else if (result == EEXIST) { - /* This GID is in use, we'll continue to the next */ - } else { - /* - * An unexpected error occurred. - * - * Only report it the first time to avoid spamming - * the logs - * - */ - if (!nospam) { - fprintf (log_get_logfd(), - _("%s: Can't get unique system GID (%s). " - "Suppressing additional messages.\n"), - log_get_progname(), strerror (result)); - SYSLOG ((LOG_ERR, - "Error checking available GIDs: %s", - strerror (result))); - nospam = 1; - } - /* - * We will continue anyway. Hopefully a later GID - * will work properly. - */ - } - } - } - } else { /* !sys_group */ - /* - * For non-system groups, we want to start from the - * bottom of the range and work upwards. - */ - - /* - * At the conclusion of the gr_next() search, we will either - * have a presumed-free GID or we will be at GID_MAX + 1. - */ - if (highest_found > gid_max) { - /* - * In this case, a GID is in use at GID_MAX. - * - * We will reset the search to GID_MIN and proceed up - * through all the GIDs (skipping those we detected with - * used_gids) for a free one. It is a known issue that - * this may result in reusing a previously-deleted GID, - * so administrators should be instructed to use this - * auto-detection with care (and prefer to assign GIDs - * explicitly). - */ - highest_found = gid_min; - } - - /* Search through all of the IDs in the range */ - for (id = highest_found; id <= gid_max; id++) { - result = check_gid (id, gid_min, gid_max, used_gids); - if (result == 0) { - /* This GID is available. Return it. */ - *gid = id; - free (used_gids); - return 0; - } else if (result == EEXIST) { - /* This GID is in use, we'll continue to the next */ - } else { - /* - * An unexpected error occurred. - * - * Only report it the first time to avoid spamming - * the logs - * - */ - if (!nospam) { - fprintf (log_get_logfd(), - _("%s: Can't get unique GID (%s). " - "Suppressing additional messages.\n"), - log_get_progname(), strerror (result)); - SYSLOG ((LOG_ERR, - "Error checking available GIDs: %s", - strerror (result))); - nospam = 1; - } - /* - * We will continue anyway. Hopefully a later GID - * will work properly. - */ - } - } - - /* - * If we get all the way through the loop, try again from GID_MIN, - * unless that was where we previously started. (NOTE: the worst-case - * scenario here is that we will run through (GID_MAX - GID_MIN - 1) - * cycles *again* if we fall into this case with highest_found as - * GID_MIN + 1, all groups in the range in use and maintained by - * network services such as LDAP.) - */ - if (highest_found != gid_min) { - for (id = gid_min; id <= gid_max; id++) { - result = check_gid (id, gid_min, gid_max, used_gids); - if (result == 0) { - /* This GID is available. Return it. */ - *gid = id; - free (used_gids); - return 0; - } else if (result == EEXIST) { - /* This GID is in use, we'll continue to the next */ - } else { - /* - * An unexpected error occurred. - * - * Only report it the first time to avoid spamming - * the logs - * - */ - if (!nospam) { - fprintf (log_get_logfd(), - _("%s: Can't get unique GID (%s). " - "Suppressing additional messages.\n"), - log_get_progname(), strerror (result)); - SYSLOG ((LOG_ERR, - "Error checking available GIDs: %s", - strerror (result))); - nospam = 1; - } - /* - * We will continue anyway. Hopefully a later GID - * will work properly. - */ - } - } - } - } - - /* The code reached here and found no available IDs in the range */ - fprintf (log_get_logfd(), - _("%s: Can't get unique GID (no more available GIDs)\n"), - log_get_progname()); - SYSLOG ((LOG_WARN, "no more available GIDs on the system")); - free (used_gids); - return -1; -} - |