[SCM] Samba Shared Repository - branch master updated
Karolin Seeger
kseeger at samba.org
Thu Apr 29 09:56:01 UTC 2021
The branch, master has been updated
via 75ad84167f5 CVE-2021-20254 passdb: Simplify sids_to_unixids()
from 757c49f6dc5 s3:winbind: For 'security = ADS' require realm/workgroup to be set
https://git.samba.org/?p=samba.git;a=shortlog;h=master
- Log -----------------------------------------------------------------
commit 75ad84167f5d2379557ec078d17c9a1c244402fc
Author: Volker Lendecke <vl at samba.org>
Date: Sat Feb 20 15:50:12 2021 +0100
CVE-2021-20254 passdb: Simplify sids_to_unixids()
Best reviewed with "git show -b", there's a "continue" statement that
changes subsequent indentation.
Decouple lookup status of ids from ID_TYPE_NOT_SPECIFIED
Add comments to explain the use of the three lookup
loops.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14571
Signed-off-by: Volker Lendecke <vl at samba.org>
Reviewed-by: Jeremy Allison <jra at samba.org>
Autobuild-User(master): Karolin Seeger <kseeger at samba.org>
Autobuild-Date(master): Thu Apr 29 09:55:51 UTC 2021 on sn-devel-184
-----------------------------------------------------------------------
Summary of changes:
source3/passdb/lookup_sid.c | 123 ++++++++++++++++++++++++++++++++++++--------
1 file changed, 101 insertions(+), 22 deletions(-)
Changeset truncated at 500 lines:
diff --git a/source3/passdb/lookup_sid.c b/source3/passdb/lookup_sid.c
index cf80a300189..0e01467b3cb 100644
--- a/source3/passdb/lookup_sid.c
+++ b/source3/passdb/lookup_sid.c
@@ -29,6 +29,7 @@
#include "../libcli/security/security.h"
#include "lib/winbind_util.h"
#include "../librpc/gen_ndr/idmap.h"
+#include "lib/util/bitmap.h"
static bool lookup_unix_user_name(const char *name, struct dom_sid *sid)
{
@@ -1266,7 +1267,9 @@ bool sids_to_unixids(const struct dom_sid *sids, uint32_t num_sids,
{
struct wbcDomainSid *wbc_sids = NULL;
struct wbcUnixId *wbc_ids = NULL;
+ struct bitmap *found = NULL;
uint32_t i, num_not_cached;
+ uint32_t wbc_ids_size = 0;
wbcErr err;
bool ret = false;
@@ -1274,6 +1277,20 @@ bool sids_to_unixids(const struct dom_sid *sids, uint32_t num_sids,
if (wbc_sids == NULL) {
return false;
}
+ found = bitmap_talloc(wbc_sids, num_sids);
+ if (found == NULL) {
+ goto fail;
+ }
+
+ /*
+ * We go through the requested SID array three times.
+ * First time to look for global_sid_Unix_Users
+ * and global_sid_Unix_Groups SIDS, and to look
+ * for mappings cached in the idmap_cache.
+ *
+ * Use bitmap_set() to mark an ids[] array entry as
+ * being mapped.
+ */
num_not_cached = 0;
@@ -1285,17 +1302,20 @@ bool sids_to_unixids(const struct dom_sid *sids, uint32_t num_sids,
&sids[i], &rid)) {
ids[i].type = ID_TYPE_UID;
ids[i].id = rid;
+ bitmap_set(found, i);
continue;
}
if (sid_peek_check_rid(&global_sid_Unix_Groups,
&sids[i], &rid)) {
ids[i].type = ID_TYPE_GID;
ids[i].id = rid;
+ bitmap_set(found, i);
continue;
}
if (idmap_cache_find_sid2unixid(&sids[i], &ids[i], &expired)
&& !expired)
{
+ bitmap_set(found, i);
continue;
}
ids[i].type = ID_TYPE_NOT_SPECIFIED;
@@ -1306,62 +1326,121 @@ bool sids_to_unixids(const struct dom_sid *sids, uint32_t num_sids,
if (num_not_cached == 0) {
goto done;
}
- wbc_ids = talloc_array(talloc_tos(), struct wbcUnixId, num_not_cached);
+
+ /*
+ * For the ones that we couldn't map in the loop above, query winbindd
+ * via wbcSidsToUnixIds().
+ */
+
+ wbc_ids_size = num_not_cached;
+ wbc_ids = talloc_array(talloc_tos(), struct wbcUnixId, wbc_ids_size);
if (wbc_ids == NULL) {
goto fail;
}
- for (i=0; i<num_not_cached; i++) {
+ for (i=0; i<wbc_ids_size; i++) {
wbc_ids[i].type = WBC_ID_TYPE_NOT_SPECIFIED;
+ wbc_ids[i].id.gid = (uint32_t)-1;
}
- err = wbcSidsToUnixIds(wbc_sids, num_not_cached, wbc_ids);
+ err = wbcSidsToUnixIds(wbc_sids, wbc_ids_size, wbc_ids);
if (!WBC_ERROR_IS_OK(err)) {
DEBUG(10, ("wbcSidsToUnixIds returned %s\n",
wbcErrorString(err)));
}
+ /*
+ * Second time through the SID array, replace
+ * the ids[] entries that wbcSidsToUnixIds() was able to
+ * map.
+ *
+ * Use bitmap_set() to mark an ids[] array entry as
+ * being mapped.
+ */
+
num_not_cached = 0;
for (i=0; i<num_sids; i++) {
- if (ids[i].type == ID_TYPE_NOT_SPECIFIED) {
- switch (wbc_ids[num_not_cached].type) {
- case WBC_ID_TYPE_UID:
- ids[i].type = ID_TYPE_UID;
- ids[i].id = wbc_ids[num_not_cached].id.uid;
- break;
- case WBC_ID_TYPE_GID:
- ids[i].type = ID_TYPE_GID;
- ids[i].id = wbc_ids[num_not_cached].id.gid;
- break;
- default:
- /* The types match, and wbcUnixId -> id is a union anyway */
- ids[i].type = (enum id_type)wbc_ids[num_not_cached].type;
- ids[i].id = wbc_ids[num_not_cached].id.gid;
- break;
- }
- num_not_cached += 1;
+ if (bitmap_query(found, i)) {
+ continue;
+ }
+
+ SMB_ASSERT(num_not_cached < wbc_ids_size);
+
+ switch (wbc_ids[num_not_cached].type) {
+ case WBC_ID_TYPE_UID:
+ ids[i].type = ID_TYPE_UID;
+ ids[i].id = wbc_ids[num_not_cached].id.uid;
+ bitmap_set(found, i);
+ break;
+ case WBC_ID_TYPE_GID:
+ ids[i].type = ID_TYPE_GID;
+ ids[i].id = wbc_ids[num_not_cached].id.gid;
+ bitmap_set(found, i);
+ break;
+ case WBC_ID_TYPE_BOTH:
+ ids[i].type = ID_TYPE_BOTH;
+ ids[i].id = wbc_ids[num_not_cached].id.uid;
+ bitmap_set(found, i);
+ break;
+ case WBC_ID_TYPE_NOT_SPECIFIED:
+ /*
+ * wbcSidsToUnixIds() wasn't able to map this
+ * so we still need to check legacy_sid_to_XXX()
+ * below. Don't mark the bitmap entry
+ * as being found so the final loop knows
+ * to try and map this entry.
+ */
+ ids[i].type = ID_TYPE_NOT_SPECIFIED;
+ ids[i].id = (uint32_t)-1;
+ break;
+ default:
+ /*
+ * A successful return from wbcSidsToUnixIds()
+ * cannot return anything other than the values
+ * checked for above. Ensure this is so.
+ */
+ smb_panic(__location__);
+ break;
}
+ num_not_cached += 1;
}
+ /*
+ * Third and final time through the SID array,
+ * try legacy_sid_to_gid()/legacy_sid_to_uid()
+ * for entries we haven't already been able to
+ * map.
+ *
+ * Use bitmap_set() to mark an ids[] array entry as
+ * being mapped.
+ */
+
for (i=0; i<num_sids; i++) {
- if (ids[i].type != ID_TYPE_NOT_SPECIFIED) {
+ if (bitmap_query(found, i)) {
continue;
}
if (legacy_sid_to_gid(&sids[i], &ids[i].id)) {
ids[i].type = ID_TYPE_GID;
+ bitmap_set(found, i);
continue;
}
if (legacy_sid_to_uid(&sids[i], &ids[i].id)) {
ids[i].type = ID_TYPE_UID;
+ bitmap_set(found, i);
continue;
}
}
done:
+ /*
+ * Pass through the return array for consistency.
+ * Any ids[].id mapped to (uint32_t)-1 must be returned
+ * as ID_TYPE_NOT_SPECIFIED.
+ */
for (i=0; i<num_sids; i++) {
switch(ids[i].type) {
case ID_TYPE_GID:
case ID_TYPE_UID:
case ID_TYPE_BOTH:
- if (ids[i].id == -1) {
+ if (ids[i].id == (uint32_t)-1) {
ids[i].type = ID_TYPE_NOT_SPECIFIED;
}
break;
--
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