int acl_readonly_example(uuid_t *uuid) { int fd; acl_t acl; acl_entry_t ace; acl_permset_t perms; filesec_t fsec; /* initialize our ACL */ if (NULL == (acl = acl_init(32))) err(1, "acl_init()"); /* * create an ACE * * acl_create_entry_np() has a position capability via the * 'entry_index' argument (ACL_FIRST_ENTRY or ACL_LAST_ENTRY) */ if (0 != acl_create_entry(&acl, &ace)) err(1, "acl_create_entry()"); /* allow or deny */ if (0 != acl_set_tag_type(ace, ACL_EXTENDED_ALLOW)) err(1, "acl_set_tag_type()"); /* associate this with our uuid */ if (0 != acl_set_qualifier(ace, uuid)) err(1, "acl_set_qualifier()"); /* grant "read only" permissions */ if (0 != acl_get_permset(ace, &perms)) err(1, "acl_get_permset()"); if (0 != acl_clear_perms(perms)) err(1, "acl_clear_perms()"); if (0 != acl_add_perm(perms, ROPERMS)) err(1, "acl_add_perm()"); if (0 != acl_set_permset(ace, perms)) err(1, "acl_set_permset()"); /* create a file security object */ fsec = filesec_init(); /* add the ACL to the security descriptor */ filesec_set_property(fsec, FILESEC_ACL, &acl); acl_free(acl); /* turn off all other permissions on the file */ filesec_set_property(fsec, FILESEC_MODE, 0); /* create a file using our ACL */ fd = openx_np("foo", O_CREAT|O_EXCL|O_RDWR, fsec); /* clean up */ filesec_free(fsec); if (-1 != fd ) close(fd); return(fd); }
int modify_file_acl(unsigned int optflags, const char *path, acl_t modifier, int position, int inheritance_level, int follow) { acl_t oacl = NULL; unsigned aindex = 0, flag_new_acl = 0; acl_entry_t newent = NULL; acl_entry_t entry = NULL; unsigned retval = 0; extern int chmod_fflag; /* XXX acl_get_file() returns a zero entry ACL if an ACL was previously * associated with the file, and has had its entries removed. * However, POSIX 1003.1e states that a zero entry ACL should be * returned if the caller asks for ACL_TYPE_DEFAULT, and no ACL is * associated with the path; it * does not specifically state that a request for ACL_TYPE_EXTENDED * should not return a zero entry ACL, however. */ /* Determine if we've been given a zero entry ACL, or create an ACL if * none exists. There are some issues to consider here: Should we create * a zero-entry ACL for a delete or check canonicity operation? */ if (path == NULL) chmod_usage(); if (optflags & ACL_CLEAR_FLAG) { filesec_t fsec = filesec_init(); if (fsec == NULL) { // err(1, "filesec_init() failed"); fprintf(stderr, "chmod: filesec_init() failed: %s\n", strerror(errno)); pthread_exit(NULL); } if (filesec_set_property(fsec, FILESEC_ACL, _FILESEC_REMOVE_ACL) != 0) { // err(1, "filesec_set_property() failed"); fprintf(stderr, "chmod: filesec_set_property() failed: %s\n", strerror(errno)); pthread_exit(NULL); } if (follow) { if (chmodx_np(path, fsec) != 0) { if (!chmod_fflag) { // warn("Failed to clear ACL on file %s", path); fprintf(stderr, "chmod: Failed to clear ACL on file %s: %s\n", path, strerror(errno)); } retval = 1; } } else { int fd = open(path, O_SYMLINK); if (fd != -1) { if (fchmodx_np(fd, fsec) != 0) { if (!chmod_fflag) { fprintf(stderr, "chmod: Failed to clear ACL on file %s: %s\n", path, strerror(errno)); // warn("Failed to clear ACL on file %s", path); } retval = 1; } close(fd); } else { if (!chmod_fflag) { // warn("Failed to open file %s", path); fprintf(stderr, "chmod: Failed to open file %s: %s\n", path, strerror(errno)); } retval = 1; } } filesec_free(fsec); return (retval); } if (optflags & ACL_FROM_STDIN) { oacl = acl_dup(modifier); } else { if (follow) { oacl = acl_get_file(path, ACL_TYPE_EXTENDED); } else { int fd = open(path, O_SYMLINK); if (fd != -1) { oacl = acl_get_fd_np(fd, ACL_TYPE_EXTENDED); close(fd); } } if ((oacl == NULL) || (acl_get_entry(oacl,ACL_FIRST_ENTRY, &newent) != 0)) { if ((oacl = acl_init(1)) == NULL) { // err(1, "acl_init() failed"); fprintf(stderr, "chmod: acl_init() failed: %s\n", strerror(errno)); pthread_exit(NULL); } flag_new_acl = 1; position = 0; } if ((0 == flag_new_acl) && (optflags & (ACL_REMOVE_INHERIT_FLAG | ACL_REMOVE_INHERITED_ENTRIES))) { acl_t facl = NULL; if ((facl = acl_init(1)) == NULL) { //err(1, "acl_init() failed"); fprintf(stderr, "chmod: acl_init() failed: %s\n", strerror(errno)); pthread_exit(NULL); } for (aindex = 0; acl_get_entry(oacl, (entry == NULL ? ACL_FIRST_ENTRY : ACL_NEXT_ENTRY), &entry) == 0; aindex++) { acl_flagset_t eflags; acl_entry_t fent = NULL; if (acl_get_flagset_np(entry, &eflags) != 0) { fprintf(stderr, "chmod: Unable to obtain flagset: %s\n", strerror(errno)); pthread_exit(NULL); // err(1, "Unable to obtain flagset"); } if (acl_get_flag_np(eflags, ACL_ENTRY_INHERITED)) { if (optflags & ACL_REMOVE_INHERIT_FLAG) { acl_delete_flag_np(eflags, ACL_ENTRY_INHERITED); acl_set_flagset_np(entry, eflags); acl_create_entry(&facl, &fent); acl_copy_entry(fent, entry); } } else { acl_create_entry(&facl, &fent); acl_copy_entry(fent, entry); } } if (oacl) acl_free(oacl); oacl = facl; } else if (optflags & ACL_TO_STDOUT) { ssize_t len; /* need to get printacl() from ls(1) */ char *text = acl_to_text(oacl, &len); puts(text); acl_free(text); } else if (optflags & ACL_CHECK_CANONICITY) { if (flag_new_acl) { // warnx("No ACL currently associated with file '%s'", path); fprintf(stderr, "chmod: No ACL currently associated with file '%s'\n", path); } retval = is_canonical(oacl); } else if ((optflags & ACL_SET_FLAG) && (position == -1) && (!is_canonical(oacl))) { // warnx("The specified file '%s' does not have an ACL in canonical order, please specify a position with +a# ", path); fprintf(stderr, "chmod: The specified file '%s' does not have an ACL in canonical order, please specify a position with +a# \n", path); retval = 1; } else if (((optflags & ACL_DELETE_FLAG) && (position != -1)) || (optflags & ACL_CHECK_CANONICITY)) { retval = modify_acl(&oacl, NULL, optflags, position, inheritance_level, flag_new_acl, path); } else if ((optflags & (ACL_REMOVE_INHERIT_FLAG|ACL_REMOVE_INHERITED_ENTRIES)) && flag_new_acl) { // warnx("No ACL currently associated with file '%s'", path); fprintf(stderr, "chmod: No ACL currently associated with file '%s'\n", path); retval = 1; } else { if (!modifier) { /* avoid bus error in acl_get_entry */ // errx(1, "Internal error: modifier should not be NULL"); fprintf(stderr, "Internal error: modifier should not be NULL\n"); pthread_exit(NULL); } for (aindex = 0; acl_get_entry(modifier, (entry == NULL ? ACL_FIRST_ENTRY : ACL_NEXT_ENTRY), &entry) == 0; aindex++) { retval += modify_acl(&oacl, entry, optflags, position, inheritance_level, flag_new_acl, path); } } } /* XXX Potential race here, since someone else could've modified or * read the ACL on this file (with the intention of modifying it) in * the interval from acl_get_file() to acl_set_file(); we can * minimize one aspect of this window by comparing the original acl * to a fresh one from acl_get_file() but we could consider a * "changeset" mechanism, common locking strategy, or kernel * supplied reservation mechanism to prevent this race. */ if (!(optflags & (ACL_TO_STDOUT|ACL_CHECK_CANONICITY))) { int status = -1; if (follow) { status = acl_set_file(path, ACL_TYPE_EXTENDED, oacl); } else { int fd = open(path, O_SYMLINK); if (fd != -1) { status = acl_set_fd_np(fd, oacl, ACL_TYPE_EXTENDED); close(fd); } } if (status != 0) { if (!chmod_fflag) fprintf(stderr, "chmod: Failed to set ACL on file '%s': %s\n", path, strerror(errno)); // warn("Failed to set ACL on file '%s'", path); retval = 1; } } if (oacl) acl_free(oacl); return retval; }