SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

core: convert exec-invoke to use the new static-friendly functions

Browse Source 
The libc API is rather ugly: it requires the caller to pass an
array of the maximum possible size (or to repeatedly query the group
list to discover the actual size). With our "static-friendly" helpers,
we reallocate the array on the fly.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2026-07-02 17:19:18 +02:00
parent 50b4f1e3bf
commit b0dfec9fa4
1 changed files with 25 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/core/exec-invoke.c
+25 -24
View File
@@ -890,7 +890,7 @@ static int get_supplementary_groups(
assert(ret_gids);
/*
* If user is given, then lookup GID and supplementary groups list.
* If user is given, then look up GID and supplementary groups list.
* We avoid NSS lookups for gid=0. Also we have to initialize groups
* here and as early as possible so we keep the list of supplementary
* groups of the caller.
@@ -898,15 +898,16 @@ static int get_supplementary_groups(
bool keep_groups = false;
if (user && gid_is_valid(gid) && gid != 0) {
/* First step, initialize groups from /etc/groups */
if (initgroups(user, gid) < 0) {
r = initgroups_wrapper(user, gid);
if (r < 0) {
/* If our primary gid is already the one specified in Group= (i.e. we're running in
* user mode), gracefully handle the case where we have no privilege to re-initgroups().
*
* Note that group memberships of the current user might have been modified, but
* the change will only take effect after re-login. It's better to continue on with
* existing credentials rather than erroring out. */
if (!ERRNO_IS_PRIVILEGE(errno) || gid != getgid())
return -errno;
if (!ERRNO_IS_PRIVILEGE(r) || gid != getgid())
return r;
}
keep_groups = true;
@@ -917,29 +918,30 @@ static int get_supplementary_groups(
return 0;
}
/* If SupplementaryGroups= was passed then NGROUPS_MAX has to be positive, otherwise fail. */
_cleanup_free_ gid_t *l_gids = NULL;
int k = 0;
if (keep_groups) {
/* Look up the list of groups that the user belongs to.
* We avoid NSS lookups here too for gid=0. */
k = getgrouplist_malloc(user, gid, &l_gids);
if (k < 0)
return k;
}
int ngroups_max = sysconf_ngroups_max();
if (ngroups_max < 0)
return ngroups_max;
_cleanup_free_ gid_t *l_gids = new(gid_t, ngroups_max);
if (!l_gids)
return -ENOMEM;
int k = 0;
if (keep_groups) {
/*
* Lookup the list of groups that the user belongs to, we
* avoid NSS lookups here too for gid=0.
*/
k = ngroups_max;
if (getgrouplist(user, gid, l_gids, &k) < 0)
return -EINVAL;
}
STRV_FOREACH(i, c->supplementary_groups) {
if (k >= ngroups_max)
return -E2BIG;
if (!GREEDY_REALLOC(l_gids, k + 1))
return -ENOMEM;
r = get_group_creds(*i, /* flags= */ 0, /* ret_name= */ NULL, l_gids + k);
if (r < 0)
return r;
@@ -952,12 +954,11 @@ static int get_supplementary_groups(
return 0;
}
/* Otherwise get the final list of supplementary groups */
gid_t *groups = newdup(gid_t, l_gids, k);
if (!groups)
return -ENOMEM;
/* We *could* trim the array size with realloc(3), but right now the only caller frees the array
* quickly anyway, so this is not worth the trouble. If other users pop up, this should be
* reconsidered. */
*ret_gids = groups;
*ret_gids = TAKE_PTR(l_gids);
return k;
}