X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2Flibadacl.c;h=e83f46be630bc40c779f9792786fa2c82e9ff944;hb=bd6889a6483bc13a05b36a4d8e37834bd50f2941;hp=0d07f2c6d0126880b59e830011fcbbefc75e797f;hpb=6727b9e8ed3807cd565127f87fa6faa33c4b5ee4;p=apply-default-acl.git

diff --git a/src/libadacl.c b/src/libadacl.c
index 0d07f2c..e83f46b 100644
--- a/src/libadacl.c
+++ b/src/libadacl.c
@@ -69,7 +69,7 @@ int safe_open_ex(int at_fd, char* pathname, int flags) {
     /* No more slashes, this is the base case. */
     return openat(at_fd, pathname, flags);
   }
-  else if (firstslash[1] == '\0') {
+  if (firstslash[1] == '\0') {
     /* The first slash is the last character; ensure that we open
        a directory. */
     firstslash[0] = '\0';
@@ -127,7 +127,7 @@ int safe_open_ex(int at_fd, char* pathname, int flags) {
  *   and @c OPEN_ERROR if not.
  */
 int safe_open(const char* pathname, int flags) {
-  if (pathname == NULL || strlen(pathname) == 0 || pathname[0] == '\0') {
+  if (pathname == NULL) {
     errno = EINVAL;
     perror("safe_open (args)");
     return OPEN_ERROR;
@@ -170,25 +170,24 @@ int safe_open(const char* pathname, int flags) {
     return OPEN_ERROR;
   }
 
-  int fd = 0;
-  if (strcmp(abspath, "/") == 0) {
-    fd = open("/", flags | O_DIRECTORY);
-  }
-  else {
+  bool abspath_is_root = (strcmp(abspath, "/") == 0);
+  int rootflags = flags | O_DIRECTORY;
+  if (!abspath_is_root) {
     /* Use O_PATH for some added safety if "/" is not our target */
-    fd = open("/", flags | O_DIRECTORY | O_PATH);
+    rootflags |= O_PATH;
   }
-  if (fd == OPEN_ERROR) {
+  int rootfd = open("/", rootflags);
+  if (rootfd == OPEN_ERROR) {
     perror("safe_open (open)");
     return OPEN_ERROR;
   }
 
-  if (strcmp(abspath, "/") == 0) {
-    return fd;
+  if (abspath_is_root) {
+    return rootfd;
   }
 
-  int result = safe_open_ex(fd, abspath+1, flags);
-  if (close(fd) == CLOSE_ERROR) {
+  int result = safe_open_ex(rootfd, abspath+1, flags);
+  if (close(rootfd) == CLOSE_ERROR) {
     perror("safe_open (close)");
     return OPEN_ERROR;
   }
@@ -199,51 +198,41 @@ int safe_open(const char* pathname, int flags) {
 
 
 /**
- * @brief Update (or create) an entry in an @b minimal ACL.
- *
- * This function will not work if @c aclp contains extended
- * entries. This is fine for our purposes, since we call @c wipe_acls
- * on each path before applying the default to it.
- *
- * The assumption that there are no extended entries makes things much
- * simpler. For example, we only have to update the @c ACL_USER_OBJ,
- * @c ACL_GROUP_OBJ, and @c ACL_OTHER entries -- all others can simply
- * be created anew. This means we don't have to fool around comparing
- * named-user/group entries.
+ * @brief Update an entry in an @b minimal ACL.
  *
  * @param aclp
- *   A pointer to the acl_t structure whose entry we want to modify.
+ *   A pointer to the acl_t structure whose entry we want to update.
  *
  * @param entry
- *   The new entry. If @c entry contains a user/group/other entry, we
- *   update the existing one. Otherwise we create a new entry.
- *
- * @return If there is an unexpected library error, @c ACL_ERROR is
- *   returned. Otherwise, @c ACL_SUCCESS.
+ *   The new entry.
  *
+ * @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_set_entry(acl_t* aclp, acl_entry_t entry) {
+int acl_update_entry(acl_t aclp, acl_entry_t entry) {
   if (aclp == NULL || entry == NULL) {
     errno = EINVAL;
-    perror("acl_set_entry (args)");
+    perror("acl_update_entry (args)");
     return ACL_ERROR;
   }
 
   acl_tag_t entry_tag;
   if (acl_get_tag_type(entry, &entry_tag) == ACL_ERROR) {
-    perror("acl_set_entry (acl_get_tag_type)");
+    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) {
-    perror("acl_set_entry (acl_get_permset)");
+    perror("acl_update_entry (acl_get_permset)");
     return ACL_ERROR;
   }
 
   acl_entry_t existing_entry;
   /* Loop through the given ACL looking for matching entries. */
-  int result = acl_get_entry(*aclp, ACL_FIRST_ENTRY, &existing_entry);
+  int result = acl_get_entry(aclp, ACL_FIRST_ENTRY, &existing_entry);
 
   while (result == ACL_SUCCESS) {
     acl_tag_t existing_tag = ACL_UNDEFINED_TAG;
@@ -256,64 +245,24 @@ int acl_set_entry(acl_t* aclp, acl_entry_t entry) {
     if (existing_tag == entry_tag) {
       /* If we update something, we're done and return ACL_SUCCESS */
       if (acl_set_permset(existing_entry, entry_permset) == ACL_ERROR) {
-        perror("acl_set_entry (acl_set_permset)");
+        perror("acl_update_entry (acl_set_permset)");
         return ACL_ERROR;
       }
 
       return ACL_SUCCESS;
     }
 
-    result = acl_get_entry(*aclp, ACL_NEXT_ENTRY, &existing_entry);
+    result = acl_get_entry(aclp, ACL_NEXT_ENTRY, &existing_entry);
   }
 
   /* This catches both the initial acl_get_entry and the ones at the
      end of the loop. */
   if (result == ACL_ERROR) {
-    perror("acl_set_entry (acl_get_entry)");
-    return ACL_ERROR;
-  }
-
-  /* If we've made it this far, we need to add a new entry to the
-     ACL. */
-  acl_entry_t new_entry;
-
-  /* The acl_create_entry() function can allocate new memory and/or
-   * change the location of the ACL structure entirely. When that
-   * happens, the value pointed to by aclp is updated, which means
-   * that a new acl_t gets "passed out" to our caller, eventually to
-   * be fed to acl_free(). In other words, we should still be freeing
-   * the right thing, even if the value pointed to by aclp changes.
-   */
-  if (acl_create_entry(aclp, &new_entry) == ACL_ERROR) {
-    perror("acl_set_entry (acl_create_entry)");
-    return ACL_ERROR;
-  }
-
-  if (acl_set_tag_type(new_entry, entry_tag) == ACL_ERROR) {
-    perror("acl_set_entry (acl_set_tag_type)");
+    perror("acl_update_entry (acl_get_entry)");
     return ACL_ERROR;
   }
 
-  if (acl_set_permset(new_entry, entry_permset) == ACL_ERROR) {
-    perror("acl_set_entry (acl_set_permset)");
-    return ACL_ERROR;
-  }
-
-  if (entry_tag == ACL_USER || entry_tag == ACL_GROUP) {
-    /* We need to set the qualifier too. */
-    void* entry_qual = acl_get_qualifier(entry);
-    if (entry_qual == (void*)NULL) {
-      perror("acl_set_entry (acl_get_qualifier)");
-      return ACL_ERROR;
-    }
-
-    if (acl_set_qualifier(new_entry, entry_qual) == ACL_ERROR) {
-      perror("acl_set_entry (acl_set_qualifier)");
-      return ACL_ERROR;
-    }
-  }
-
-  return ACL_SUCCESS;
+  return ACL_FAILURE;
 }
 
 
@@ -551,38 +500,6 @@ int any_can_execute(int fd, const struct stat* sp) {
 
 
 
-/**
- * @brief Remove all @c ACL_TYPE_ACCESS entries from the given file
- *   descriptor, leaving the UNIX permission bits.
- *
- * @param fd
- *   The file descriptor whose ACLs we want to wipe.
- *
- * @return
- *   - @c ACL_SUCCESS - The ACLs were wiped successfully, or none
- *     existed in the first place.
- *   - @c ACL_ERROR - Unexpected library error.
- */
-int wipe_acls(int fd) {
-  /* Initialize an empty ACL, and then overwrite the one on "fd" with it. */
-  acl_t empty_acl = acl_init(0);
-
-  if (empty_acl == (acl_t)NULL) {
-    perror("wipe_acls (acl_init)");
-    return ACL_ERROR;
-  }
-
-  if (acl_set_fd(fd, empty_acl) == ACL_ERROR) {
-    perror("wipe_acls (acl_set_fd)");
-    acl_free(empty_acl);
-    return ACL_ERROR;
-  }
-
-  acl_free(empty_acl);
-  return ACL_SUCCESS;
-}
-
-
 /**
  * @brief Copy ACLs between file descriptors as xattrs, verbatim.
  *
@@ -649,7 +566,7 @@ int acl_copy_xattr(int src_fd,
     return ACL_ERROR;
   }
 
-  size_t src_size_guess = fgetxattr(src_fd, src_name, NULL, 0);
+  ssize_t src_size_guess = fgetxattr(src_fd, src_name, NULL, 0);
   if (src_size_guess == XATTR_ERROR) {
     if (errno == ENODATA) {
       /* A missing ACL isn't really an error. ENOATTR and ENODATA are
@@ -662,7 +579,7 @@ int acl_copy_xattr(int src_fd,
   }
   char* src_acl_p = alloca(src_size_guess);
   /* The actual size may be smaller than our guess? I don't know. */
-  size_t src_size = fgetxattr(src_fd, src_name, src_acl_p, (int)src_size_guess);
+  ssize_t src_size = fgetxattr(src_fd, src_name, src_acl_p, src_size_guess);
   if (src_size == XATTR_ERROR) {
     if (errno == ENODATA) {
       /* A missing ACL isn't an error. */
@@ -713,10 +630,6 @@ int has_default_acl_fd(int fd) {
  * @param path
  *   The path whose ACL we would like to reset to its default.
  *
- * @param sp
- *   A pointer to a stat structure for @c path, or @c NULL if you don't
- *   have one handy.
- *
  * @param no_exec_mask
  *   The value (either true or false) of the --no-exec-mask flag.
  *
@@ -725,13 +638,11 @@ int has_default_acl_fd(int fd) {
  *   - @c ACL_FAILURE - If symlinks or hard links are encountered.
  *   - @c ACL_ERROR - Unexpected library error.
  */
-int apply_default_acl_ex(const char* path,
-                         const struct stat* sp,
-                         bool no_exec_mask) {
+int apply_default_acl(const char* path, bool no_exec_mask) {
 
   if (path == NULL) {
     errno = EINVAL;
-    perror("apply_default_acl_ex (args)");
+    perror("apply_default_acl (args)");
     return ACL_ERROR;
   }
 
@@ -755,14 +666,19 @@ int apply_default_acl_ex(const char* path,
   /* The file descriptor for the directory containing "path" */
   int parent_fd = 0;
 
+  /* dirname() and basename() mangle their arguments, so we need
+     to make copies of "path" before using them. */
+  char* dirname_path_copy = NULL;
+  char* basename_path_copy = NULL;
+
   /* Get the parent directory of "path" with dirname(), which happens
    * to murder its argument and necessitates a path_copy. */
-  char* path_copy = strdup(path);
-  if (path_copy == NULL) {
-    perror("apply_default_acl_ex (strdup)");
+  dirname_path_copy = strdup(path);
+  if (dirname_path_copy == NULL) {
+    perror("apply_default_acl (strdup)");
     return ACL_ERROR;
   }
-  char* parent = dirname(path_copy);
+  char* parent = dirname(dirname_path_copy);
   parent_fd = safe_open(parent, O_DIRECTORY | O_NOFOLLOW);
   if (parent_fd == OPEN_ERROR) {
     if (errno == ELOOP || errno == ENOTDIR) {
@@ -772,7 +688,7 @@ int apply_default_acl_ex(const char* path,
       goto cleanup;
     }
     else {
-      perror("apply_default_acl_ex (open parent fd)");
+      perror("apply_default_acl (open parent fd)");
       result = ACL_ERROR;
       goto cleanup;
     }
@@ -785,7 +701,16 @@ int apply_default_acl_ex(const char* path,
     goto cleanup;
   }
 
-  fd = safe_open(path, O_NOFOLLOW);
+  /* We already obtained the parent fd safely, so if we use the
+     basename of path here instead of the full thing, then we can get
+     away with using openat() and spare ourselves the slowness of
+     another safe_open(). */
+  basename_path_copy = strdup(path);
+  if (basename_path_copy == NULL) {
+    perror("apply_default_acl (strdup)");
+    return ACL_ERROR;
+  }
+  fd = openat(parent_fd, basename(basename_path_copy), O_NOFOLLOW);
   if (fd == OPEN_ERROR) {
     if (errno == ELOOP || errno == ENOTDIR) {
       /* We hit a symlink, either in the last path component (ELOOP)
@@ -794,7 +719,7 @@ int apply_default_acl_ex(const char* path,
       goto cleanup;
     }
     else {
-      perror("apply_default_acl_ex (open fd)");
+      perror("apply_default_acl (open fd)");
       result = ACL_ERROR;
       goto cleanup;
     }
@@ -806,24 +731,17 @@ int apply_default_acl_ex(const char* path,
    * race condition here, but the window is as small as possible
    * between when we open the file descriptor (look above) and when we
    * fstat it.
-   *
-   * Note: we only need to call fstat ourselves if we weren't passed a
-   * valid pointer to a stat structure (nftw does that).
   */
-  if (sp == NULL) {
-    struct stat s;
-    if (fstat(fd, &s) == STAT_ERROR) {
-      perror("apply_default_acl_ex (fstat)");
-      goto cleanup;
-    }
-
-    sp = &s;
+  struct stat s;
+  if (fstat(fd, &s) == STAT_ERROR) {
+    perror("apply_default_acl (fstat)");
+    goto cleanup;
   }
 
-  if (!S_ISDIR(sp->st_mode)) {
+  if (!S_ISDIR(s.st_mode)) {
     /* If it's not a directory, make sure it's a regular,
        non-hard-linked file. */
-    if (!S_ISREG(sp->st_mode) || sp->st_nlink != 1) {
+    if (!S_ISREG(s.st_mode) || s.st_nlink != 1) {
       result = ACL_FAILURE;
       goto cleanup;
     }
@@ -838,10 +756,10 @@ int apply_default_acl_ex(const char* path,
 
   if (!no_exec_mask) {
     /* Never mask the execute bit on directories. */
-    int ace_result = any_can_execute(fd,sp) || S_ISDIR(sp->st_mode);
+    int ace_result = any_can_execute(fd,&s) || S_ISDIR(s.st_mode);
 
     if (ace_result == ACL_ERROR) {
-      perror("apply_default_acl_ex (any_can_execute)");
+      perror("apply_default_acl (any_can_execute)");
       result = ACL_ERROR;
       goto cleanup;
     }
@@ -849,19 +767,13 @@ int apply_default_acl_ex(const char* path,
     allow_exec = (bool)ace_result;
   }
 
-  if (wipe_acls(fd) == ACL_ERROR) {
-    perror("apply_default_acl_ex (wipe_acls)");
-    result = ACL_ERROR;
-    goto cleanup;
-  }
-
   /* If it's a directory, inherit the parent's default.  */
-  if (S_ISDIR(sp->st_mode)) {
+  if (S_ISDIR(s.st_mode)) {
     if (acl_copy_xattr(parent_fd,
                        ACL_TYPE_DEFAULT,
                        fd,
                        ACL_TYPE_DEFAULT) == ACL_ERROR) {
-      perror("apply_default_acl_ex (acl_copy_xattr default)");
+      perror("apply_default_acl (acl_copy_xattr default)");
       result = ACL_ERROR;
       goto cleanup;
     }
@@ -872,13 +784,13 @@ int apply_default_acl_ex(const char* path,
                      ACL_TYPE_DEFAULT,
                      fd,
                      ACL_TYPE_ACCESS) == ACL_ERROR) {
-    perror("apply_default_acl_ex (acl_copy_xattr access)");
+    perror("apply_default_acl (acl_copy_xattr access)");
     result = ACL_ERROR;
     goto cleanup;
   }
 
   /* There's a good reason why we saved the ACL above, even though
-   * we're about tto read it back into memory and mess with it on the
+   * we're about to read it back into memory and mess with it on the
    * next line. The acl_copy_xattr() function is already a hack to let
    * us copy default ACLs without resorting to path names; we simply
    * have no way to read the parent's default ACL into memory using
@@ -889,10 +801,16 @@ int apply_default_acl_ex(const char* path,
   */
 
   /* Now we potentially need to mask the execute permissions in the
-     ACL on fd. First obtain the current one... */
+     ACL on fd; or maybe not. */
+  if (allow_exec) {
+    goto cleanup;
+  }
+
+  /* OK, we need to mask some execute permissions. First obtain the
+     current ACL... */
   new_acl = acl_get_fd(fd);
   if (new_acl == (acl_t)NULL) {
-    perror("apply_default_acl_ex (acl_get_fd)");
+    perror("apply_default_acl (acl_get_fd)");
     result = ACL_ERROR;
     goto cleanup;
   }
@@ -902,7 +820,7 @@ int apply_default_acl_ex(const char* path,
      looping over it no worky). */
   new_acl_unmasked = acl_dup(new_acl);
   if (new_acl_unmasked == (acl_t)NULL) {
-    perror("apply_default_acl_ex (acl_dup)");
+    perror("apply_default_acl (acl_dup)");
     result = ACL_ERROR;
     goto cleanup;
   }
@@ -914,7 +832,7 @@ int apply_default_acl_ex(const char* path,
     acl_tag_t tag = ACL_UNDEFINED_TAG;
 
     if (acl_get_tag_type(entry, &tag) == ACL_ERROR) {
-       perror("apply_default_acl_ex (acl_get_tag_type)");
+       perror("apply_default_acl (acl_get_tag_type)");
        result = ACL_ERROR;
        goto cleanup;
     }
@@ -923,7 +841,7 @@ int apply_default_acl_ex(const char* path,
     /* We've got an entry/tag from the default ACL. Get its permset. */
     acl_permset_t permset;
     if (acl_get_permset(entry, &permset) == ACL_ERROR) {
-      perror("apply_default_acl_ex (acl_get_permset)");
+      perror("apply_default_acl (acl_get_permset)");
       result = ACL_ERROR;
       goto cleanup;
     }
@@ -933,43 +851,24 @@ int apply_default_acl_ex(const char* path,
         tag == ACL_GROUP_OBJ ||
         tag == ACL_OTHER) {
 
-      if (!allow_exec) {
-        /* The mask doesn't affect acl_user_obj, acl_group_obj (in
-           minimal ACLs) or acl_other entries, so if execute should be
-           masked, we have to do it manually. */
-        if (acl_delete_perm(permset, ACL_EXECUTE) == ACL_ERROR) {
-          perror("apply_default_acl_ex (acl_delete_perm)");
-          result = ACL_ERROR;
-          goto cleanup;
-        }
-
-        if (acl_set_permset(entry, permset) == ACL_ERROR) {
-          perror("apply_default_acl_ex (acl_set_permset)");
-          result = ACL_ERROR;
-          goto cleanup;
-        }
+      /* The mask doesn't affect acl_user_obj, acl_group_obj (in
+         minimal ACLs) or acl_other entries, so if execute should be
+         masked, we have to do it manually. */
+      if (acl_delete_perm(permset, ACL_EXECUTE) == ACL_ERROR) {
+        perror("apply_default_acl (acl_delete_perm)");
+        result = ACL_ERROR;
+        goto cleanup;
+      }
+
+      if (acl_set_permset(entry, permset) == ACL_ERROR) {
+        perror("apply_default_acl (acl_set_permset)");
+        result = ACL_ERROR;
+        goto cleanup;
       }
     }
 
-    /* Finally, add the permset to the access ACL. It's actually
-     * important that we pass in the address of "new_acl" here, and not
-     * "new_acl" itself. Why? The call to acl_create_entry() within
-     * acl_set_entry() can allocate new memory for the entry.
-     * Sometimes that can be done in-place, in which case everything
-     * is cool and the new memory gets released when we call
-     * acl_free(acl).
-     *
-     * But occasionally, the whole ACL structure will have to be moved
-     * in order to allocate the extra space. When that happens,
-     * acl_create_entry() modifies the pointer it was passed (in this
-     * case, &acl) to point to the new location. We want to call
-     * acl_free() on the new location, and since acl_free() gets
-     * called right here, we need acl_create_entry() to update the
-     * value of "new_acl". To do that, it needs the address of "new_acl".
-     */
-
-    if (acl_set_entry(&new_acl, entry) == ACL_ERROR) {
-      perror("apply_default_acl_ex (acl_set_entry)");
+    if (acl_update_entry(new_acl, entry) == ACL_ERROR) {
+      perror("apply_default_acl (acl_update_entry)");
       result = ACL_ERROR;
       goto cleanup;
     }
@@ -980,60 +879,30 @@ int apply_default_acl_ex(const char* path,
   /* Catches the first acl_get_entry as well as the ones at the end of
      the loop. */
   if (ge_result == ACL_ERROR) {
-    perror("apply_default_acl_ex (acl_get_entry)");
+    perror("apply_default_acl (acl_get_entry)");
     result = ACL_ERROR;
     goto cleanup;
   }
 
   if (acl_set_fd(fd, new_acl) == ACL_ERROR) {
-    perror("apply_default_acl_ex (acl_set_fd)");
+    perror("apply_default_acl (acl_set_fd)");
     result = ACL_ERROR;
     goto cleanup;
   }
 
  cleanup:
-  free(path_copy);
-  if (new_acl != (acl_t)NULL) {
-    acl_free(new_acl);
-  }
-  if (new_acl_unmasked != (acl_t)NULL) {
-    acl_free(new_acl_unmasked);
-  }
+  free(dirname_path_copy);
+  free(basename_path_copy);
+  acl_free(new_acl);
+  acl_free(new_acl_unmasked);
+
   if (fd > 0 && close(fd) == CLOSE_ERROR) {
-    perror("apply_default_acl_ex (close fd)");
+    perror("apply_default_acl (close fd)");
     result = ACL_ERROR;
   }
   if (parent_fd > 0 && close(parent_fd) == CLOSE_ERROR) {
-    perror("apply_default_acl_ex (close parent_fd)");
+    perror("apply_default_acl (close parent_fd)");
     result = ACL_ERROR;
   }
   return result;
 }
-
-
-
-/**
- * @brief The friendly interface to @c apply_default_acl_ex.
- *
- * The @c apply_default_acl_ex function holds the real implementation
- * of this function, but it takes a weird second argument that most
- * people won't care about (a stat structure). But, we use that
- * argument for the recursive mode of the CLI, so it's there.
- *
- * If you don't have a stat structure for your @c path, use this instead.
- *
- * @param path
- *   The path whose ACL we would like to reset to its default.
- *
- * @param no_exec_mask
- *   The value (either true or false) of the --no-exec-mask flag.
- *
- * @return
- *   - @c ACL_SUCCESS - The parent default ACL was inherited successfully.
- *   - @c ACL_FAILURE - If symlinks or hard links are encountered.
- *     or the parent of @c path is not a directory.
- *   - @c ACL_ERROR - Unexpected library error.
- */
-int apply_default_acl(const char* path, bool no_exec_mask) {
-  return apply_default_acl_ex(path, NULL, no_exec_mask);
-}