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-rw-r--r--src/libshared/acl-util.c429
1 files changed, 429 insertions, 0 deletions
diff --git a/src/libshared/acl-util.c b/src/libshared/acl-util.c
new file mode 100644
index 0000000000..2aa951fce9
--- /dev/null
+++ b/src/libshared/acl-util.c
@@ -0,0 +1,429 @@
+/***
+ This file is part of systemd.
+
+ Copyright 2011,2013 Lennart Poettering
+
+ systemd 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.
+
+ systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <stdbool.h>
+
+#include "acl-util.h"
+#include "alloc-util.h"
+#include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
+#include "util.h"
+
+int acl_find_uid(acl_t acl, uid_t uid, acl_entry_t *entry) {
+ acl_entry_t i;
+ int r;
+
+ assert(acl);
+ assert(entry);
+
+ for (r = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
+ r > 0;
+ r = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) {
+
+ acl_tag_t tag;
+ uid_t *u;
+ bool b;
+
+ if (acl_get_tag_type(i, &tag) < 0)
+ return -errno;
+
+ if (tag != ACL_USER)
+ continue;
+
+ u = acl_get_qualifier(i);
+ if (!u)
+ return -errno;
+
+ b = *u == uid;
+ acl_free(u);
+
+ if (b) {
+ *entry = i;
+ return 1;
+ }
+ }
+ if (r < 0)
+ return -errno;
+
+ return 0;
+}
+
+int calc_acl_mask_if_needed(acl_t *acl_p) {
+ acl_entry_t i;
+ int r;
+ bool need = false;
+
+ assert(acl_p);
+
+ for (r = acl_get_entry(*acl_p, ACL_FIRST_ENTRY, &i);
+ r > 0;
+ r = acl_get_entry(*acl_p, ACL_NEXT_ENTRY, &i)) {
+ acl_tag_t tag;
+
+ if (acl_get_tag_type(i, &tag) < 0)
+ return -errno;
+
+ if (tag == ACL_MASK)
+ return 0;
+
+ if (IN_SET(tag, ACL_USER, ACL_GROUP))
+ need = true;
+ }
+ if (r < 0)
+ return -errno;
+
+ if (need && acl_calc_mask(acl_p) < 0)
+ return -errno;
+
+ return need;
+}
+
+int add_base_acls_if_needed(acl_t *acl_p, const char *path) {
+ acl_entry_t i;
+ int r;
+ bool have_user_obj = false, have_group_obj = false, have_other = false;
+ struct stat st;
+ _cleanup_(acl_freep) acl_t basic = NULL;
+
+ assert(acl_p);
+
+ for (r = acl_get_entry(*acl_p, ACL_FIRST_ENTRY, &i);
+ r > 0;
+ r = acl_get_entry(*acl_p, ACL_NEXT_ENTRY, &i)) {
+ acl_tag_t tag;
+
+ if (acl_get_tag_type(i, &tag) < 0)
+ return -errno;
+
+ if (tag == ACL_USER_OBJ)
+ have_user_obj = true;
+ else if (tag == ACL_GROUP_OBJ)
+ have_group_obj = true;
+ else if (tag == ACL_OTHER)
+ have_other = true;
+ if (have_user_obj && have_group_obj && have_other)
+ return 0;
+ }
+ if (r < 0)
+ return -errno;
+
+ r = stat(path, &st);
+ if (r < 0)
+ return -errno;
+
+ basic = acl_from_mode(st.st_mode);
+ if (!basic)
+ return -errno;
+
+ for (r = acl_get_entry(basic, ACL_FIRST_ENTRY, &i);
+ r > 0;
+ r = acl_get_entry(basic, ACL_NEXT_ENTRY, &i)) {
+ acl_tag_t tag;
+ acl_entry_t dst;
+
+ if (acl_get_tag_type(i, &tag) < 0)
+ return -errno;
+
+ if ((tag == ACL_USER_OBJ && have_user_obj) ||
+ (tag == ACL_GROUP_OBJ && have_group_obj) ||
+ (tag == ACL_OTHER && have_other))
+ continue;
+
+ r = acl_create_entry(acl_p, &dst);
+ if (r < 0)
+ return -errno;
+
+ r = acl_copy_entry(dst, i);
+ if (r < 0)
+ return -errno;
+ }
+ if (r < 0)
+ return -errno;
+ return 0;
+}
+
+int acl_search_groups(const char *path, char ***ret_groups) {
+ _cleanup_strv_free_ char **g = NULL;
+ _cleanup_(acl_free) acl_t acl = NULL;
+ bool ret = false;
+ acl_entry_t entry;
+ int r;
+
+ assert(path);
+
+ acl = acl_get_file(path, ACL_TYPE_DEFAULT);
+ if (!acl)
+ return -errno;
+
+ r = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);
+ for (;;) {
+ _cleanup_(acl_free_gid_tpp) gid_t *gid = NULL;
+ acl_tag_t tag;
+
+ if (r < 0)
+ return -errno;
+ if (r == 0)
+ break;
+
+ if (acl_get_tag_type(entry, &tag) < 0)
+ return -errno;
+
+ if (tag != ACL_GROUP)
+ goto next;
+
+ gid = acl_get_qualifier(entry);
+ if (!gid)
+ return -errno;
+
+ if (in_gid(*gid) > 0) {
+ if (!ret_groups)
+ return true;
+
+ ret = true;
+ }
+
+ if (ret_groups) {
+ char *name;
+
+ name = gid_to_name(*gid);
+ if (!name)
+ return -ENOMEM;
+
+ r = strv_consume(&g, name);
+ if (r < 0)
+ return r;
+ }
+
+ next:
+ r = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry);
+ }
+
+ if (ret_groups) {
+ *ret_groups = g;
+ g = NULL;
+ }
+
+ return ret;
+}
+
+int parse_acl(const char *text, acl_t *acl_access, acl_t *acl_default, bool want_mask) {
+ _cleanup_free_ char **a = NULL, **d = NULL; /* strings are not be freed */
+ _cleanup_strv_free_ char **split;
+ char **entry;
+ int r = -EINVAL;
+ _cleanup_(acl_freep) acl_t a_acl = NULL, d_acl = NULL;
+
+ split = strv_split(text, ",");
+ if (!split)
+ return -ENOMEM;
+
+ STRV_FOREACH(entry, split) {
+ char *p;
+
+ p = startswith(*entry, "default:");
+ if (!p)
+ p = startswith(*entry, "d:");
+
+ if (p)
+ r = strv_push(&d, p);
+ else
+ r = strv_push(&a, *entry);
+ if (r < 0)
+ return r;
+ }
+
+ if (!strv_isempty(a)) {
+ _cleanup_free_ char *join;
+
+ join = strv_join(a, ",");
+ if (!join)
+ return -ENOMEM;
+
+ a_acl = acl_from_text(join);
+ if (!a_acl)
+ return -errno;
+
+ if (want_mask) {
+ r = calc_acl_mask_if_needed(&a_acl);
+ if (r < 0)
+ return r;
+ }
+ }
+
+ if (!strv_isempty(d)) {
+ _cleanup_free_ char *join;
+
+ join = strv_join(d, ",");
+ if (!join)
+ return -ENOMEM;
+
+ d_acl = acl_from_text(join);
+ if (!d_acl)
+ return -errno;
+
+ if (want_mask) {
+ r = calc_acl_mask_if_needed(&d_acl);
+ if (r < 0)
+ return r;
+ }
+ }
+
+ *acl_access = a_acl;
+ *acl_default = d_acl;
+ a_acl = d_acl = NULL;
+
+ return 0;
+}
+
+static int acl_entry_equal(acl_entry_t a, acl_entry_t b) {
+ acl_tag_t tag_a, tag_b;
+
+ if (acl_get_tag_type(a, &tag_a) < 0)
+ return -errno;
+
+ if (acl_get_tag_type(b, &tag_b) < 0)
+ return -errno;
+
+ if (tag_a != tag_b)
+ return false;
+
+ switch (tag_a) {
+ case ACL_USER_OBJ:
+ case ACL_GROUP_OBJ:
+ case ACL_MASK:
+ case ACL_OTHER:
+ /* can have only one of those */
+ return true;
+ case ACL_USER: {
+ _cleanup_(acl_free_uid_tpp) uid_t *uid_a = NULL, *uid_b = NULL;
+
+ uid_a = acl_get_qualifier(a);
+ if (!uid_a)
+ return -errno;
+
+ uid_b = acl_get_qualifier(b);
+ if (!uid_b)
+ return -errno;
+
+ return *uid_a == *uid_b;
+ }
+ case ACL_GROUP: {
+ _cleanup_(acl_free_gid_tpp) gid_t *gid_a = NULL, *gid_b = NULL;
+
+ gid_a = acl_get_qualifier(a);
+ if (!gid_a)
+ return -errno;
+
+ gid_b = acl_get_qualifier(b);
+ if (!gid_b)
+ return -errno;
+
+ return *gid_a == *gid_b;
+ }
+ default:
+ assert_not_reached("Unknown acl tag type");
+ }
+}
+
+static int find_acl_entry(acl_t acl, acl_entry_t entry, acl_entry_t *out) {
+ acl_entry_t i;
+ int r;
+
+ for (r = acl_get_entry(acl, ACL_FIRST_ENTRY, &i);
+ r > 0;
+ r = acl_get_entry(acl, ACL_NEXT_ENTRY, &i)) {
+
+ r = acl_entry_equal(i, entry);
+ if (r < 0)
+ return r;
+ if (r > 0) {
+ *out = i;
+ return 1;
+ }
+ }
+ if (r < 0)
+ return -errno;
+ return 0;
+}
+
+int acls_for_file(const char *path, acl_type_t type, acl_t new, acl_t *acl) {
+ _cleanup_(acl_freep) acl_t old;
+ acl_entry_t i;
+ int r;
+
+ old = acl_get_file(path, type);
+ if (!old)
+ return -errno;
+
+ for (r = acl_get_entry(new, ACL_FIRST_ENTRY, &i);
+ r > 0;
+ r = acl_get_entry(new, ACL_NEXT_ENTRY, &i)) {
+
+ acl_entry_t j;
+
+ r = find_acl_entry(old, i, &j);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ if (acl_create_entry(&old, &j) < 0)
+ return -errno;
+
+ if (acl_copy_entry(j, i) < 0)
+ return -errno;
+ }
+ if (r < 0)
+ return -errno;
+
+ *acl = old;
+ old = NULL;
+ return 0;
+}
+
+int add_acls_for_user(int fd, uid_t uid) {
+ _cleanup_(acl_freep) acl_t acl = NULL;
+ acl_entry_t entry;
+ acl_permset_t permset;
+ int r;
+
+ acl = acl_get_fd(fd);
+ if (!acl)
+ return -errno;
+
+ r = acl_find_uid(acl, uid, &entry);
+ if (r <= 0) {
+ if (acl_create_entry(&acl, &entry) < 0 ||
+ acl_set_tag_type(entry, ACL_USER) < 0 ||
+ acl_set_qualifier(entry, &uid) < 0)
+ return -errno;
+ }
+
+ /* We do not recalculate the mask unconditionally here,
+ * so that the fchmod() mask above stays intact. */
+ if (acl_get_permset(entry, &permset) < 0 ||
+ acl_add_perm(permset, ACL_READ) < 0)
+ return -errno;
+
+ r = calc_acl_mask_if_needed(&acl);
+ if (r < 0)
+ return r;
+
+ return acl_set_fd(fd, acl);
+}
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