+/**
+ * @file apply-default-acl.c
+ *
+ * @brief The entire implementation.
+ *
+ */
+
/* On Linux, ftw.h needs this special voodoo to work. */
#define _XOPEN_SOURCE 500
+#define _GNU_SOURCE
#include <errno.h>
#include <ftw.h> /* nftw() et al. */
#include <sys/types.h>
#include <sys/acl.h>
+/* Most of the libacl functions return 1 for success, 0 for failure,
+ and -1 on error */
+#define ACL_ERROR -1
+#define ACL_FAILURE 0
+#define ACL_SUCCESS 1
+
+
+/* Command-line options */
+static bool no_exec_mask = false;
+
+
+/**
+ * @brief Get the mode bits from the given path.
+ *
+ * @param path
+ * The path (file or directory) whose mode we want.
+ *
+ * @return A mode_t (st_mode) structure containing the mode bits.
+ * See sys/stat.h for details.
+ */
mode_t get_mode(const char* path) {
- /*
- * Get the mode bits from path.
- */
if (path == NULL) {
errno = ENOENT;
return -1;
}
+
+/**
+ * @brief Determine whether or not the given path is a regular file.
+ *
+ * @param path
+ * The path to test.
+ *
+ * @return true if @c path is a regular file, false otherwise.
+ */
bool is_regular_file(const char* path) {
- /*
- * Returns true if path is a regular file, false otherwise.
- */
if (path == NULL) {
return false;
}
}
}
+
+
+/**
+ * @brief Determine whether or not the given path is a directory.
+ *
+ * @param path
+ * The path to test.
+ *
+ * @return true if @c path is a directory, false otherwise.
+ */
bool is_directory(const char* path) {
- /*
- * Returns true if path is a directory, false otherwise.
- */
if (path == NULL) {
return false;
}
+/**
+ * @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 ACL_USER_OBJ,
+ * ACL_GROUP_OBJ, and ACL_OTHER entries -- all others can simply be
+ * created anew. This means we don't have to fool around comparing
+ * named-user/group entries.
+ *
+ * @param aclp
+ * A pointer to the acl_t structure whose entry we want to modify.
+ *
+ * @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, ACL_ERROR is
+ * returned. Otherwise, ACL_SUCCESS.
+ *
+ */
int acl_set_entry(acl_t* aclp,
acl_entry_t entry) {
- /*
- * Update or create the given entry.
- */
acl_tag_t entry_tag;
int gt_result = acl_get_tag_type(entry, &entry_tag);
- if (gt_result == -1) {
+ if (gt_result == ACL_ERROR) {
perror("acl_set_entry (acl_get_tag_type)");
- return -1;
+ return ACL_ERROR;
}
acl_permset_t entry_permset;
int ps_result = acl_get_permset(entry, &entry_permset);
- if (ps_result == -1) {
+ if (ps_result == ACL_ERROR) {
perror("acl_set_entry (acl_get_permset)");
- return -1;
+ 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);
- while (result == 1) {
+ while (result == ACL_SUCCESS) {
acl_tag_t existing_tag = ACL_UNDEFINED_TAG;
int tag_result = acl_get_tag_type(existing_entry, &existing_tag);
- if (tag_result == -1) {
+ if (tag_result == ACL_ERROR) {
perror("set_acl_tag_permset (acl_get_tag_type)");
- return -1;
+ return ACL_ERROR;
}
if (existing_tag == entry_tag) {
entry_tag == ACL_GROUP_OBJ ||
entry_tag == ACL_OTHER) {
/* Only update for these three since all other tags will have
- been wiped. */
+ been wiped. These three are guaranteed to exist, so if we
+ match one of them, we're allowed to return ACL_SUCCESS
+ below and bypass the rest of the function. */
acl_permset_t existing_permset;
int gep_result = acl_get_permset(existing_entry, &existing_permset);
- if (gep_result == -1) {
+ if (gep_result == ACL_ERROR) {
perror("acl_set_entry (acl_get_permset)");
- return -1;
+ return ACL_ERROR;
}
int s_result = acl_set_permset(existing_entry, entry_permset);
- if (s_result == -1) {
+ if (s_result == ACL_ERROR) {
perror("acl_set_entry (acl_set_permset)");
- return -1;
+ return ACL_ERROR;
}
- return 1;
+ return ACL_SUCCESS;
}
}
/* This catches both the initial acl_get_entry and the ones at the
end of the loop. */
- if (result == -1) {
+ if (result == ACL_ERROR) {
perror("acl_set_entry (acl_get_entry)");
- return -1;
+ return ACL_ERROR;
}
/* If we've made it this far, we need to add a new entry to the
/* We allocate memory here that we should release! */
int c_result = acl_create_entry(aclp, &new_entry);
- if (c_result == -1) {
+ if (c_result == ACL_ERROR) {
perror("acl_set_entry (acl_create_entry)");
- return -1;
+ return ACL_ERROR;
}
int st_result = acl_set_tag_type(new_entry, entry_tag);
- if (st_result == -1) {
+ if (st_result == ACL_ERROR) {
perror("acl_set_entry (acl_set_tag_type)");
- return -1;
+ return ACL_ERROR;
}
int s_result = acl_set_permset(new_entry, entry_permset);
- if (s_result == -1) {
+ if (s_result == ACL_ERROR) {
perror("acl_set_entry (acl_set_permset)");
- return -1;
+ return ACL_ERROR;
}
if (entry_tag == ACL_USER || entry_tag == ACL_GROUP) {
void* entry_qual = acl_get_qualifier(entry);
if (entry_qual == (void*)NULL) {
perror("acl_set_entry (acl_get_qualifier)");
- return -1;
+ return ACL_ERROR;
}
int sq_result = acl_set_qualifier(new_entry, entry_qual);
- if (sq_result == -1) {
+ if (sq_result == ACL_ERROR) {
perror("acl_set_entry (acl_set_qualifier)");
- return -1;
+ return ACL_ERROR;
}
}
- return 1;
+ return ACL_SUCCESS;
}
+/**
+ * @brief Determine the number of entries in the given ACL.
+ *
+ * @param acl
+ * A pointer to an acl_t structure.
+ *
+ * @return Either the non-negative number of entries in @c acl, or
+ * ACL_ERROR on error.
+ */
int acl_entry_count(acl_t* acl) {
- /*
- * Return the number of entries in acl, or -1 on error.
- */
+
acl_entry_t entry;
int entry_count = 0;
int result = acl_get_entry(*acl, ACL_FIRST_ENTRY, &entry);
- while (result == 1) {
+ while (result == ACL_SUCCESS) {
entry_count++;
result = acl_get_entry(*acl, ACL_NEXT_ENTRY, &entry);
}
- if (result == -1) {
- perror("acl_is_minimal (acl_get_entry)");
- return -1;
+ if (result == ACL_ERROR) {
+ perror("acl_entry_count (acl_get_entry)");
+ return ACL_ERROR;
}
return entry_count;
}
+
+/**
+ * @brief Determine whether or not the given ACL is minimal.
+ *
+ * An ACL is minimal if it has fewer than four entries.
+ *
+ * @param acl
+ * A pointer to an acl_t structure.
+ *
+ * @return
+ * - ACL_SUCCESS - @c acl is minimal
+ * - ACL_FAILURE - @c acl is not minimal
+ * - ACL_ERROR - Unexpected library error
+ */
int acl_is_minimal(acl_t* acl) {
- /* An ACL is minimal if it has fewer than four entries. Return 0 for
- * false, 1 for true, and -1 on error.
- */
int ec = acl_entry_count(acl);
- if (ec == -1) {
+
+ if (ec == ACL_ERROR) {
perror("acl_is_minimal (acl_entry_count)");
- return -1;
+ return ACL_ERROR;
}
if (ec < 4) {
- return 1;
+ return ACL_SUCCESS;
}
else {
- return 0;
+ return ACL_FAILURE;
}
}
-int any_can_execute(const char* path) {
- /* Returns 1 if any ACL entry has execute access, 0 if none do, and
- * -1 on error.
- */
+
+/**
+ * @brief Determine whether the given path has an ACL whose mask
+ * denies execute.
+ *
+ * @param path
+ * The path to check.
+ *
+ * @return
+ * - ACL_SUCCESS - @c path has a mask which denies execute.
+ * - ACL_FAILURE - The ACL for @c path does not deny execute,
+ * or @c path has no extended ACL at all.
+ * - ACL_ERROR - Unexpected library error.
+ */
+int acl_execute_masked(const char* path) {
+
+ acl_t acl = acl_get_file(path, ACL_TYPE_ACCESS);
+
+ if (acl == (acl_t)NULL) {
+ perror("acl_execute_masked (acl_get_file)");
+ return ACL_ERROR;
+ }
+
+ /* Our return value. */
+ int result = ACL_FAILURE;
+
+ acl_entry_t entry;
+ int ge_result = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);
+
+ while (ge_result == ACL_SUCCESS) {
+ acl_tag_t tag = ACL_UNDEFINED_TAG;
+ int tag_result = acl_get_tag_type(entry, &tag);
+
+ if (tag_result == ACL_ERROR) {
+ perror("acl_execute_masked (acl_get_tag_type)");
+ result = ACL_ERROR;
+ goto cleanup;
+ }
+
+ if (tag == ACL_MASK) {
+ /* This is the mask entry, get its permissions, and see if
+ execute is specified. */
+ acl_permset_t permset;
+
+ int ps_result = acl_get_permset(entry, &permset);
+ if (ps_result == ACL_ERROR) {
+ perror("acl_execute_masked (acl_get_permset)");
+ result = ACL_ERROR;
+ goto cleanup;
+ }
+
+ int gp_result = acl_get_perm(permset, ACL_EXECUTE);
+ if (gp_result == ACL_ERROR) {
+ perror("acl_execute_masked (acl_get_perm)");
+ result = ACL_ERROR;
+ goto cleanup;
+ }
+
+ if (gp_result == ACL_FAILURE) {
+ /* No execute bit set in the mask; execute not allowed. */
+ return ACL_SUCCESS;
+ }
+ }
+
+ ge_result = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry);
+ }
+
+ cleanup:
+ acl_free(acl);
+ return result;
+}
+
+
+/**
+ * @brief Determine whether @c path is executable (by anyone) or a
+ * directory.
+ *
+ * This is used as part of the heuristic to determine whether or not
+ * we should mask the execute bit when inheriting an ACL. If @c path
+ * is a directory, the answer is a clear-cut yes. This behavior is
+ * modeled after the capital 'X' perms of setfacl.
+ *
+ * If @c path is a file, we check the @a effective permissions,
+ * contrary to what setfacl does.
+ *
+ * @param path
+ * The path to check.
+ *
+ * @return
+ * - ACL_SUCCESS - @c path is a directory, or someone has effective
+ execute permissions.
+ * - ACL_FAILURE - @c path is a regular file and nobody can execute it.
+ * - ACL_ERROR - Unexpected library error.
+ */
+int any_can_execute_or_dir(const char* path) {
+
+ if (is_directory(path)) {
+ /* That was easy... */
+ return ACL_SUCCESS;
+ }
+
acl_t acl = acl_get_file(path, ACL_TYPE_ACCESS);
if (acl == (acl_t)NULL) {
- return 0;
+ perror("any_can_execute_or_dir (acl_get_file)");
+ return ACL_ERROR;
}
/* Our return value. */
- int result = 0;
+ int result = ACL_FAILURE;
if (acl_is_minimal(&acl)) {
mode_t mode = get_mode(path);
if (mode & (S_IXUSR | S_IXOTH | S_IXGRP)) {
- result = 1;
+ result = ACL_SUCCESS;
goto cleanup;
}
else {
- result = 0;
+ result = ACL_FAILURE;
goto cleanup;
}
}
acl_entry_t entry;
int ge_result = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);
- while (ge_result == 1) {
+ while (ge_result == ACL_SUCCESS) {
acl_permset_t permset;
int ps_result = acl_get_permset(entry, &permset);
- if (ps_result == -1) {
- perror("any_can_execute (acl_get_permset)");
- result = -1;
+ if (ps_result == ACL_ERROR) {
+ perror("any_can_execute_or_dir (acl_get_permset)");
+ result = ACL_ERROR;
goto cleanup;
}
int gp_result = acl_get_perm(permset, ACL_EXECUTE);
- if (gp_result == -1) {
- perror("any_can_execute (acl_get_perm)");
- result = -1;
+ if (gp_result == ACL_ERROR) {
+ perror("any_can_execute_or_dir (acl_get_perm)");
+ result = ACL_ERROR;
goto cleanup;
}
- if (gp_result == 1) {
- result = 1;
- goto cleanup;
+ if (gp_result == ACL_SUCCESS) {
+ /* Only return one if this execute bit is not masked. */
+ if (acl_execute_masked(path) != ACL_SUCCESS) {
+ result = ACL_SUCCESS;
+ goto cleanup;
+ }
}
ge_result = acl_get_entry(acl, ACL_NEXT_ENTRY, &entry);
}
- if (ge_result == -1) {
- perror("any_can_execute (acl_get_entry)");
- result = -1;
+ if (ge_result == ACL_ERROR) {
+ perror("any_can_execute_or_dir (acl_get_entry)");
+ result = ACL_ERROR;
goto cleanup;
}
}
+
+/**
+ * @brief Inherit the default ACL from @c parent to @c path.
+ *
+ * The @c parent parameter does not necessarily need to be the parent
+ * of @c path, although that will usually be the case. This overwrites
+ * any existing default ACL on @c path.
+ *
+ * @param parent
+ * The parent directory whose ACL we want to inherit.
+ *
+ * @param path
+ * The target directory whose ACL we wish to overwrite (or create).
+ *
+ * @return
+ * - ACL_SUCCESS - The default ACL was inherited successfully.
+ * - ACL_FAILURE - Either @c parent or @c path is not a directory.
+ * - ACL_ERROR - Unexpected library error.
+ */
int inherit_default_acl(const char* path, const char* parent) {
/* Inherit the default ACL from parent to path. This overwrites any
* existing default ACL. Returns 1 for success, 0 for failure, and
*/
/* Our return value. */
- int result = 1;
+ int result = ACL_SUCCESS;
if (path == NULL) {
errno = ENOENT;
- return -1;
+ return ACL_ERROR;
}
if (!is_directory(path) || !is_directory(parent)) {
- return 0;
+ return ACL_FAILURE;
}
acl_t parent_acl = acl_get_file(parent, ACL_TYPE_DEFAULT);
if (parent_acl == (acl_t)NULL) {
- return 0;
+ perror("inherit_default_acl (acl_get_file)");
+ return ACL_ERROR;
}
acl_t path_acl = acl_dup(parent_acl);
if (path_acl == (acl_t)NULL) {
perror("inherit_default_acl (acl_dup)");
acl_free(parent_acl);
- return -1;
+ return ACL_ERROR;
}
int sf_result = acl_set_file(path, ACL_TYPE_DEFAULT, path_acl);
if (sf_result == -1) {
perror("inherit_default_acl (acl_set_file)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
if (path == NULL) {
errno = ENOENT;
- return -1;
+ return ACL_ERROR;
}
/* Finally, remove individual named/mask entries. */
acl_t acl = acl_get_file(path, ACL_TYPE_ACCESS);
if (acl == (acl_t)NULL) {
perror("wipe_acls (acl_get_file)");
- return -1;
+ return ACL_ERROR;
}
/* Our return value. */
- int result = 1;
+ int result = ACL_SUCCESS;
acl_entry_t entry;
int ge_result = acl_get_entry(acl, ACL_FIRST_ENTRY, &entry);
- while (ge_result == 1) {
+ while (ge_result == ACL_SUCCESS) {
int d_result = acl_delete_entry(acl, entry);
- if (d_result == -1) {
+ if (d_result == ACL_ERROR) {
perror("wipe_acls (acl_delete_entry)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
/* Catches the first acl_get_entry as well as the ones at the end of
the loop. */
- if (ge_result == -1) {
+ if (ge_result == ACL_ERROR) {
perror("wipe_acls (acl_get_entry)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
int sf_result = acl_set_file(path, ACL_TYPE_ACCESS, acl);
- if (sf_result == -1) {
+ if (sf_result == ACL_ERROR) {
perror("wipe_acls (acl_set_file)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
/* Really apply the default ACL by looping through it. Returns one
* for success, zero for failure (i.e. no ACL), and -1 on unexpected
* errors.
+
*/
if (path == NULL) {
- return 0;
+ return ACL_FAILURE;
}
if (!is_regular_file(path) && !is_directory(path)) {
- return 0;
+ return ACL_FAILURE;
}
/* dirname mangles its argument */
char* parent = dirname(path_copy);
if (!is_directory(parent)) {
/* Make sure dirname() did what we think it did. */
- return 0;
+ return ACL_FAILURE;
}
- int ace_result = any_can_execute(path);
- if (ace_result == -1) {
- perror("apply_default_acl (any_can_execute)");
- return -1;
- }
+ /* Default to not masking the exec bit; i.e. applying the default
+ ACL literally. If --no-exec-mask was not specified, then we try
+ to "guess" whether or not to mask the exec bit. */
+ bool allow_exec = true;
+
+ if (!no_exec_mask) {
+ int ace_result = any_can_execute_or_dir(path);
- bool allow_exec = (bool)ace_result;
+ if (ace_result == ACL_ERROR) {
+ perror("apply_default_acl (any_can_execute_or_dir)");
+ return ACL_ERROR;
+ }
+ allow_exec = (bool)ace_result;
+ }
acl_t defacl = acl_get_file(parent, ACL_TYPE_DEFAULT);
if (defacl == (acl_t)NULL) {
perror("apply_default_acl (acl_get_file)");
- return -1;
+ return ACL_ERROR;
}
/* Our return value. */
- int result = 1;
+ int result = ACL_SUCCESS;
int wipe_result = wipe_acls(path);
- if (wipe_result == -1) {
+ if (wipe_result == ACL_ERROR) {
perror("apply_default_acl (wipe_acls)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
acl_t acl = acl_get_file(path, ACL_TYPE_ACCESS);
if (acl == (acl_t)NULL) {
perror("apply_default_acl (acl_get_file)");
- return -1;
+ return ACL_ERROR;
}
/* If it's a directory, inherit the parent's default. */
int inherit_result = inherit_default_acl(path, parent);
- if (inherit_result == -1) {
+ if (inherit_result == ACL_ERROR) {
perror("apply_default_acl (inherit_acls)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
acl_entry_t entry;
int ge_result = acl_get_entry(defacl, ACL_FIRST_ENTRY, &entry);
- while (ge_result == 1) {
+ while (ge_result == ACL_SUCCESS) {
acl_tag_t tag = ACL_UNDEFINED_TAG;
int tag_result = acl_get_tag_type(entry, &tag);
- if (tag_result == -1) {
- perror("has_default_tag_acl (acl_get_tag_type)");
- result = -1;
+ if (tag_result == ACL_ERROR) {
+ perror("apply_default_acl (acl_get_tag_type)");
+ result = ACL_ERROR;
goto cleanup;
}
/* We've got an entry/tag from the default ACL. Get its permset. */
acl_permset_t permset;
int ps_result = acl_get_permset(entry, &permset);
- if (ps_result == -1) {
+ if (ps_result == ACL_ERROR) {
perror("apply_default_acl (acl_get_permset)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
tag == ACL_USER_OBJ ||
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. */
int d_result = acl_delete_perm(permset, ACL_EXECUTE);
- if (d_result == -1) {
+ if (d_result == ACL_ERROR) {
perror("apply_default_acl (acl_delete_perm)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
int sp_result = acl_set_permset(entry, permset);
- if (sp_result == -1) {
+ if (sp_result == ACL_ERROR) {
perror("apply_default_acl (acl_set_permset)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
}
/* Finally, add the permset to the access ACL. */
int set_result = acl_set_entry(&acl, entry);
- if (set_result == -1) {
+ if (set_result == ACL_ERROR) {
perror("apply_default_acl (acl_set_entry)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
/* Catches the first acl_get_entry as well as the ones at the end of
the loop. */
- if (ge_result == -1) {
+ if (ge_result == ACL_ERROR) {
perror("apply_default_acl (acl_get_entry)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
int sf_result = acl_set_file(path, ACL_TYPE_ACCESS, acl);
- if (sf_result == -1) {
+ if (sf_result == ACL_ERROR) {
perror("apply_default_acl (acl_set_file)");
- result = -1;
+ result = ACL_ERROR;
goto cleanup;
}
printf("Flags:\n");
printf(" -h, --help Print this help message\n");
printf(" -r, --recursive Act on any given directories recursively\n");
+ printf(" -x, --no-exec-mask Apply execute permissions unconditionally\n");
+
+ return;
}
int apply_default_acl_nftw(const char *target,
- const struct stat *s,
- int info,
- struct FTW *ftw) {
+ const struct stat *s,
+ int info,
+ struct FTW *ftw) {
/* A wrapper around the apply_default_acl() function for use with
* nftw(). We need to adjust the return value so that nftw() doesn't
* think we've failed.
*/
bool reapp_result = apply_default_acl(target);
if (reapp_result) {
- return 0;
+ return FTW_CONTINUE;
}
else {
- return 1;
+ return FTW_STOP;
}
}
return EXIT_FAILURE;
}
-
bool recursive = false;
+ /* bool no_exec_mask is declared static/global */
struct option long_options[] = {
/* These options set a flag. */
{"help", no_argument, NULL, 'h'},
{"recursive", no_argument, NULL, 'r'},
+ {"no-exec-mask", no_argument, NULL, 'x'},
{NULL, 0, NULL, 0}
};
int opt = 0;
- while ((opt = getopt_long(argc, argv, "hr", long_options, NULL)) != -1) {
+ while ((opt = getopt_long(argc, argv, "hrx", long_options, NULL)) != -1) {
switch (opt) {
case 'h':
usage(argv[0]);
case 'r':
recursive = true;
break;
+ case 'x':
+ no_exec_mask = true;
+ break;
default:
usage(argv[0]);
return EXIT_FAILURE;
projects / apply-default-acl.git / blobdiff