[PATCH 2/3] libsemanage: remove access() check to make setuid programs work

[Vit Mojzis]

F_OK access checks only work properly as long as all directories along
the path are accessible to real user running the program.
Replace F_OK access checks by testing return value of open, write, etc.

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1186431
---
 libsemanage/src/direct_api.c | 36 +++++++++++++++---------------------
 1 file changed, 15 insertions(+), 21 deletions(-)

diff --git a/libsemanage/src/direct_api.c b/libsemanage/src/direct_api.c
index b761b68..ed11a7c 100644
--- a/libsemanage/src/direct_api.c
+++ b/libsemanage/src/direct_api.c
@@ -1538,33 +1538,27 @@ rebuild:
        }
 
        path = semanage_path(SEMANAGE_TMP, SEMANAGE_STORE_FC_LOCAL);
-       if (access(path, F_OK) == 0) {
-               retval = semanage_copy_file(semanage_path(SEMANAGE_TMP, 
SEMANAGE_STORE_FC_LOCAL),
-                                                       
semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL),
-                                                       sh->conf->file_mode);
-               if (retval < 0) {
-                       goto cleanup;
-               }
+       retval = semanage_copy_file(semanage_path(SEMANAGE_TMP, 
SEMANAGE_STORE_FC_LOCAL),
+                                               
semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC_LOCAL),
+                                               sh->conf->file_mode);
+       if (retval < 0 && errno != ENOENT) {
+               goto cleanup;
        }
 
        path = semanage_path(SEMANAGE_TMP, SEMANAGE_STORE_FC);
-       if (access(path, F_OK) == 0) {
-               retval = semanage_copy_file(semanage_path(SEMANAGE_TMP, 
SEMANAGE_STORE_FC),
-                                                       
semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC),
-                                                       sh->conf->file_mode);
-               if (retval < 0) {
-                       goto cleanup;
-               }
+       retval = semanage_copy_file(semanage_path(SEMANAGE_TMP, 
SEMANAGE_STORE_FC),
+                                               
semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_FC),
+                                               sh->conf->file_mode);
+       if (retval < 0 && errno != ENOENT) {
+               goto cleanup;
        }
 
        path = semanage_path(SEMANAGE_TMP, SEMANAGE_STORE_SEUSERS);
-       if (access(path, F_OK) == 0) {
-               retval = semanage_copy_file(semanage_path(SEMANAGE_TMP, 
SEMANAGE_STORE_SEUSERS),
-                                                       
semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_SEUSERS),
-                                                       sh->conf->file_mode);
-               if (retval < 0) {
-                       goto cleanup;
-               }
+       retval = semanage_copy_file(semanage_path(SEMANAGE_TMP, 
SEMANAGE_STORE_SEUSERS),
+                                               
semanage_final_path(SEMANAGE_FINAL_TMP, SEMANAGE_SEUSERS),
+                                               sh->conf->file_mode);
+       if (retval < 0 && errno != ENOENT) {
+               goto cleanup;
        }
 
        /* run genhomedircon if its enabled, this should be the last operation
-- 
2.9.4