X-Git-Url: http://gitweb.michael.orlitzky.com/?p=apply-default-acl.git;a=blobdiff_plain;f=src%2Flibadacl.c;h=a21aa709ba842bc7bd21aa672b99b4e3cb750cf0;hp=aa473c4d696db186e2271d3ed92a09ed9c48596b;hb=HEAD;hpb=9c3d24f7347f6f9f7a8c5fdf0c7f649ce5fb927a

diff --git a/src/libadacl.c b/src/libadacl.c
index aa473c4..a21aa70 100644
--- a/src/libadacl.c
+++ b/src/libadacl.c
@@ -14,6 +14,7 @@
 #include <errno.h>      /* EINVAL, ELOOP, ENOTDIR, etc. */
 #include <fcntl.h>      /* openat() */
 #include <libgen.h>     /* basename(), dirname() */
+#include <limits.h>     /* PATH_MAX */
 #include <stdbool.h>    /* the "bool" type */
 #include <stdio.h>      /* perror(), asprintf() */
 #include <stdlib.h>     /* free() */
@@ -45,7 +46,7 @@
 /* Prototypes */
 int safe_open_ex(int at_fd, char* pathname, int flags);
 int safe_open(const char* pathname, int flags);
-int acl_update_entry(acl_t aclp, acl_entry_t entry);
+int acl_update_entry(acl_t aclp, acl_entry_t updated_entry);
 int acl_entry_count(acl_t acl);
 int acl_is_minimal(acl_t acl);
 int acl_execute_masked(acl_t acl);
@@ -232,38 +233,38 @@ int safe_open(const char* pathname, int flags) {
  * @param aclp
  *   A pointer to the acl_t structure whose entry we want to update.
  *
- * @param entry
- *   The new entry.
+ * @param updated_entry
+ *   An updated copy of an existing entry in @c aclp.
  *
  * @return
  *   - @c ACL_SUCCESS - If we update an existing entry.
  *   - @c ACL_FAILURE - If we don't find an entry to update.
  *   - @c ACL_ERROR - Unexpected library error.
  */
-int acl_update_entry(acl_t aclp, acl_entry_t entry) {
-  if (aclp == NULL || entry == NULL) {
+int acl_update_entry(acl_t aclp, acl_entry_t updated_entry) {
+  if (aclp == NULL || updated_entry == NULL) {
     errno = EINVAL;
     perror("acl_update_entry (args)");
     return ACL_ERROR;
   }
 
-  acl_tag_t entry_tag;
-  if (acl_get_tag_type(entry, &entry_tag) == ACL_ERROR) {
+  acl_tag_t updated_tag;
+  if (acl_get_tag_type(updated_entry, &updated_tag) == ACL_ERROR) {
     perror("acl_update_entry (acl_get_tag_type)");
     return ACL_ERROR;
   }
 
-  acl_permset_t entry_permset;
-  if (acl_get_permset(entry, &entry_permset) == ACL_ERROR) {
+  acl_permset_t updated_permset;
+  if (acl_get_permset(updated_entry, &updated_permset) == ACL_ERROR) {
     perror("acl_update_entry (acl_get_permset)");
     return ACL_ERROR;
   }
 
   /* This can allocate memory, so from here on out we have to jump to
      the "cleanup" label to exit. */
-  void* entry_qualifier = acl_get_qualifier(entry);
-  if (entry_qualifier == NULL &&
-      (entry_tag == ACL_USER || entry_tag == ACL_GROUP)) {
+  void* updated_qualifier = acl_get_qualifier(updated_entry);
+  if (updated_qualifier == NULL &&
+      (updated_tag == ACL_USER || updated_tag == ACL_GROUP)) {
     /* acl_get_qualifier() can return NULL, but it shouldn't for
        ACL_USER or ACL_GROUP entries. */
     perror("acl_update_entry (acl_get_qualifier)");
@@ -287,7 +288,7 @@ int acl_update_entry(acl_t aclp, acl_entry_t entry) {
        goto cleanup;
     }
 
-    if (existing_tag == entry_tag) {
+    if (existing_tag == updated_tag) {
       /* Our tag types match, but if we have a named user or group
          entry, then we need to check that the user/group (that is,
          the qualifier) matches too. */
@@ -309,16 +310,23 @@ int acl_update_entry(acl_t aclp, acl_entry_t entry) {
         }
       }
 
-      /* Otherwise, we have to have matching UIDs or GIDs. */
-      if (entry_tag == ACL_USER) {
+      /* Second, they could have matching UIDs. We don't really need to
+         check both tags here, since we know that they're equal. However,
+         clang-tidy can't figure that out, and the redundant equality
+         check prevents it from complaining about a potential null pointer
+         dereference. */
+      if (updated_tag == ACL_USER && existing_tag == ACL_USER) {
         qualifiers_match = ( *((uid_t*)existing_qualifier)
                              ==
-                             *((uid_t*)entry_qualifier) );
+                             *((uid_t*)updated_qualifier) );
       }
-      else if (entry_tag == ACL_GROUP) {
+
+      /* Third, they could have matching GIDs. See above for why
+         we check the redundant condition existing_tag == ACL_GROUP. */
+      if (updated_tag == ACL_GROUP && existing_tag == ACL_GROUP) {
         qualifiers_match = ( *((gid_t*)existing_qualifier)
                              ==
-                             *((gid_t*)entry_qualifier) );
+                             *((gid_t*)updated_qualifier) );
       }
 
       /* Be sure to free this inside the loop, where memory is allocated. */
@@ -326,13 +334,13 @@ int acl_update_entry(acl_t aclp, acl_entry_t entry) {
 
       if (qualifiers_match) {
         /* If we update something, we're done and return ACL_SUCCESS */
-        if (acl_set_permset(existing_entry, entry_permset) == ACL_ERROR) {
+        if (acl_set_permset(existing_entry, updated_permset) == ACL_ERROR) {
           perror("acl_update_entry (acl_set_permset)");
           result = ACL_ERROR;
           goto cleanup;
         }
 
-	result = ACL_SUCCESS;
+        result = ACL_SUCCESS;
         goto cleanup;
       }
     }
@@ -348,7 +356,7 @@ int acl_update_entry(acl_t aclp, acl_entry_t entry) {
   }
 
  cleanup:
-  acl_free(entry_qualifier);
+  acl_free(updated_qualifier);
   return result;
 }