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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 02:25:50 +0000 |
commit | 19f4f86bfed21c5326ed2acebe1163f3a83e832b (patch) | |
tree | d59b9989ce55ed23693e80974d94c856f1c2c8b1 /src/shared/condition.c | |
parent | Initial commit. (diff) | |
download | systemd-upstream.tar.xz systemd-upstream.zip |
Adding upstream version 241.upstream/241upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/shared/condition.c')
-rw-r--r-- | src/shared/condition.c | 733 |
1 files changed, 733 insertions, 0 deletions
diff --git a/src/shared/condition.c b/src/shared/condition.c new file mode 100644 index 0000000..fb77966 --- /dev/null +++ b/src/shared/condition.c @@ -0,0 +1,733 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <fcntl.h> +#include <fnmatch.h> +#include <limits.h> +#include <stdlib.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/utsname.h> +#include <time.h> +#include <unistd.h> + +#include "sd-id128.h" + +#include "alloc-util.h" +#include "apparmor-util.h" +#include "architecture.h" +#include "audit-util.h" +#include "cap-list.h" +#include "cgroup-util.h" +#include "condition.h" +#include "efivars.h" +#include "extract-word.h" +#include "fd-util.h" +#include "fileio.h" +#include "glob-util.h" +#include "hostname-util.h" +#include "ima-util.h" +#include "list.h" +#include "macro.h" +#include "mountpoint-util.h" +#include "env-file.h" +#include "parse-util.h" +#include "path-util.h" +#include "proc-cmdline.h" +#include "process-util.h" +#include "selinux-util.h" +#include "smack-util.h" +#include "stat-util.h" +#include "string-table.h" +#include "string-util.h" +#include "tomoyo-util.h" +#include "user-util.h" +#include "util.h" +#include "virt.h" + +Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) { + Condition *c; + int r; + + assert(type >= 0); + assert(type < _CONDITION_TYPE_MAX); + assert((!parameter) == (type == CONDITION_NULL)); + + c = new0(Condition, 1); + if (!c) + return NULL; + + c->type = type; + c->trigger = trigger; + c->negate = negate; + + r = free_and_strdup(&c->parameter, parameter); + if (r < 0) { + return mfree(c); + } + + return c; +} + +void condition_free(Condition *c) { + assert(c); + + free(c->parameter); + free(c); +} + +Condition* condition_free_list(Condition *first) { + Condition *c, *n; + + LIST_FOREACH_SAFE(conditions, c, n, first) + condition_free(c); + + return NULL; +} + +static int condition_test_kernel_command_line(Condition *c) { + _cleanup_free_ char *line = NULL; + const char *p; + bool equal; + int r; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_KERNEL_COMMAND_LINE); + + r = proc_cmdline(&line); + if (r < 0) + return r; + + equal = strchr(c->parameter, '='); + + for (p = line;;) { + _cleanup_free_ char *word = NULL; + bool found; + + r = extract_first_word(&p, &word, NULL, EXTRACT_QUOTES|EXTRACT_RELAX); + if (r < 0) + return r; + if (r == 0) + break; + + if (equal) + found = streq(word, c->parameter); + else { + const char *f; + + f = startswith(word, c->parameter); + found = f && IN_SET(*f, 0, '='); + } + + if (found) + return true; + } + + return false; +} + +static int condition_test_kernel_version(Condition *c) { + enum { + /* Listed in order of checking. Note that some comparators are prefixes of others, hence the longest + * should be listed first. */ + LOWER_OR_EQUAL, + GREATER_OR_EQUAL, + LOWER, + GREATER, + EQUAL, + _ORDER_MAX, + }; + + static const char *const prefix[_ORDER_MAX] = { + [LOWER_OR_EQUAL] = "<=", + [GREATER_OR_EQUAL] = ">=", + [LOWER] = "<", + [GREATER] = ">", + [EQUAL] = "=", + }; + const char *p = NULL; + struct utsname u; + size_t i; + int k; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_KERNEL_VERSION); + + assert_se(uname(&u) >= 0); + + for (i = 0; i < _ORDER_MAX; i++) { + p = startswith(c->parameter, prefix[i]); + if (p) + break; + } + + /* No prefix? Then treat as glob string */ + if (!p) + return fnmatch(skip_leading_chars(c->parameter, NULL), u.release, 0) == 0; + + k = str_verscmp(u.release, skip_leading_chars(p, NULL)); + + switch (i) { + + case LOWER: + return k < 0; + + case LOWER_OR_EQUAL: + return k <= 0; + + case EQUAL: + return k == 0; + + case GREATER_OR_EQUAL: + return k >= 0; + + case GREATER: + return k > 0; + + default: + assert_not_reached("Can't compare"); + } +} + +static int condition_test_user(Condition *c) { + uid_t id; + int r; + _cleanup_free_ char *username = NULL; + const char *u; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_USER); + + r = parse_uid(c->parameter, &id); + if (r >= 0) + return id == getuid() || id == geteuid(); + + if (streq("@system", c->parameter)) + return uid_is_system(getuid()) || uid_is_system(geteuid()); + + username = getusername_malloc(); + if (!username) + return -ENOMEM; + + if (streq(username, c->parameter)) + return 1; + + if (getpid_cached() == 1) + return streq(c->parameter, "root"); + + u = c->parameter; + r = get_user_creds(&u, &id, NULL, NULL, NULL, USER_CREDS_ALLOW_MISSING); + if (r < 0) + return 0; + + return id == getuid() || id == geteuid(); +} + +static int condition_test_control_group_controller(Condition *c) { + int r; + CGroupMask system_mask, wanted_mask = 0; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_CONTROL_GROUP_CONTROLLER); + + r = cg_mask_supported(&system_mask); + if (r < 0) + return log_debug_errno(r, "Failed to determine supported controllers: %m"); + + r = cg_mask_from_string(c->parameter, &wanted_mask); + if (r < 0 || wanted_mask <= 0) { + /* This won't catch the case that we have an unknown controller + * mixed in with valid ones -- these are only assessed on the + * validity of the valid controllers found. */ + log_debug("Failed to parse cgroup string: %s", c->parameter); + return 1; + } + + return FLAGS_SET(system_mask, wanted_mask); +} + +static int condition_test_group(Condition *c) { + gid_t id; + int r; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_GROUP); + + r = parse_gid(c->parameter, &id); + if (r >= 0) + return in_gid(id); + + /* Avoid any NSS lookups if we are PID1 */ + if (getpid_cached() == 1) + return streq(c->parameter, "root"); + + return in_group(c->parameter) > 0; +} + +static int condition_test_virtualization(Condition *c) { + int b, v; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_VIRTUALIZATION); + + if (streq(c->parameter, "private-users")) + return running_in_userns(); + + v = detect_virtualization(); + if (v < 0) + return v; + + /* First, compare with yes/no */ + b = parse_boolean(c->parameter); + if (b >= 0) + return b == !!v; + + /* Then, compare categorization */ + if (streq(c->parameter, "vm")) + return VIRTUALIZATION_IS_VM(v); + + if (streq(c->parameter, "container")) + return VIRTUALIZATION_IS_CONTAINER(v); + + /* Finally compare id */ + return v != VIRTUALIZATION_NONE && streq(c->parameter, virtualization_to_string(v)); +} + +static int condition_test_architecture(Condition *c) { + int a, b; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_ARCHITECTURE); + + a = uname_architecture(); + if (a < 0) + return a; + + if (streq(c->parameter, "native")) + b = native_architecture(); + else { + b = architecture_from_string(c->parameter); + if (b < 0) /* unknown architecture? Then it's definitely not ours */ + return false; + } + + return a == b; +} + +static int condition_test_host(Condition *c) { + _cleanup_free_ char *h = NULL; + sd_id128_t x, y; + int r; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_HOST); + + if (sd_id128_from_string(c->parameter, &x) >= 0) { + + r = sd_id128_get_machine(&y); + if (r < 0) + return r; + + return sd_id128_equal(x, y); + } + + h = gethostname_malloc(); + if (!h) + return -ENOMEM; + + return fnmatch(c->parameter, h, FNM_CASEFOLD) == 0; +} + +static int condition_test_ac_power(Condition *c) { + int r; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_AC_POWER); + + r = parse_boolean(c->parameter); + if (r < 0) + return r; + + return (on_ac_power() != 0) == !!r; +} + +static int condition_test_security(Condition *c) { + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_SECURITY); + + if (streq(c->parameter, "selinux")) + return mac_selinux_use(); + if (streq(c->parameter, "smack")) + return mac_smack_use(); + if (streq(c->parameter, "apparmor")) + return mac_apparmor_use(); + if (streq(c->parameter, "audit")) + return use_audit(); + if (streq(c->parameter, "ima")) + return use_ima(); + if (streq(c->parameter, "tomoyo")) + return mac_tomoyo_use(); + if (streq(c->parameter, "uefi-secureboot")) + return is_efi_secure_boot(); + + return false; +} + +static int condition_test_capability(Condition *c) { + unsigned long long capabilities = (unsigned long long) -1; + _cleanup_fclose_ FILE *f = NULL; + int value, r; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_CAPABILITY); + + /* If it's an invalid capability, we don't have it */ + value = capability_from_name(c->parameter); + if (value < 0) + return -EINVAL; + + /* If it's a valid capability we default to assume + * that we have it */ + + f = fopen("/proc/self/status", "re"); + if (!f) + return -errno; + + for (;;) { + _cleanup_free_ char *line = NULL; + const char *p; + + r = read_line(f, LONG_LINE_MAX, &line); + if (r < 0) + return r; + if (r == 0) + break; + + p = startswith(line, "CapBnd:"); + if (p) { + if (sscanf(line+7, "%llx", &capabilities) != 1) + return -EIO; + + break; + } + } + + return !!(capabilities & (1ULL << value)); +} + +static int condition_test_needs_update(Condition *c) { + const char *p; + struct stat usr, other; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_NEEDS_UPDATE); + + /* If the file system is read-only we shouldn't suggest an update */ + if (path_is_read_only_fs(c->parameter) > 0) + return false; + + /* Any other failure means we should allow the condition to be true, + * so that we rather invoke too many update tools than too + * few. */ + + if (!path_is_absolute(c->parameter)) + return true; + + p = strjoina(c->parameter, "/.updated"); + if (lstat(p, &other) < 0) + return true; + + if (lstat("/usr/", &usr) < 0) + return true; + + /* + * First, compare seconds as they are always accurate... + */ + if (usr.st_mtim.tv_sec != other.st_mtim.tv_sec) + return usr.st_mtim.tv_sec > other.st_mtim.tv_sec; + + /* + * ...then compare nanoseconds. + * + * A false positive is only possible when /usr's nanoseconds > 0 + * (otherwise /usr cannot be strictly newer than the target file) + * AND the target file's nanoseconds == 0 + * (otherwise the filesystem supports nsec timestamps, see stat(2)). + */ + if (usr.st_mtim.tv_nsec > 0 && other.st_mtim.tv_nsec == 0) { + _cleanup_free_ char *timestamp_str = NULL; + uint64_t timestamp; + int r; + + r = parse_env_file(NULL, p, "TIMESTAMP_NSEC", ×tamp_str); + if (r < 0) { + log_error_errno(r, "Failed to parse timestamp file '%s', using mtime: %m", p); + return true; + } else if (r == 0) { + log_debug("No data in timestamp file '%s', using mtime", p); + return true; + } + + r = safe_atou64(timestamp_str, ×tamp); + if (r < 0) { + log_error_errno(r, "Failed to parse timestamp value '%s' in file '%s', using mtime: %m", timestamp_str, p); + return true; + } + + timespec_store(&other.st_mtim, timestamp); + } + + return usr.st_mtim.tv_nsec > other.st_mtim.tv_nsec; +} + +static int condition_test_first_boot(Condition *c) { + int r; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_FIRST_BOOT); + + r = parse_boolean(c->parameter); + if (r < 0) + return r; + + return (access("/run/systemd/first-boot", F_OK) >= 0) == !!r; +} + +static int condition_test_path_exists(Condition *c) { + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_PATH_EXISTS); + + return access(c->parameter, F_OK) >= 0; +} + +static int condition_test_path_exists_glob(Condition *c) { + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_PATH_EXISTS_GLOB); + + return glob_exists(c->parameter) > 0; +} + +static int condition_test_path_is_directory(Condition *c) { + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_PATH_IS_DIRECTORY); + + return is_dir(c->parameter, true) > 0; +} + +static int condition_test_path_is_symbolic_link(Condition *c) { + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_PATH_IS_SYMBOLIC_LINK); + + return is_symlink(c->parameter) > 0; +} + +static int condition_test_path_is_mount_point(Condition *c) { + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_PATH_IS_MOUNT_POINT); + + return path_is_mount_point(c->parameter, NULL, AT_SYMLINK_FOLLOW) > 0; +} + +static int condition_test_path_is_read_write(Condition *c) { + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_PATH_IS_READ_WRITE); + + return path_is_read_only_fs(c->parameter) <= 0; +} + +static int condition_test_directory_not_empty(Condition *c) { + int r; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_DIRECTORY_NOT_EMPTY); + + r = dir_is_empty(c->parameter); + return r <= 0 && r != -ENOENT; +} + +static int condition_test_file_not_empty(Condition *c) { + struct stat st; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_FILE_NOT_EMPTY); + + return (stat(c->parameter, &st) >= 0 && + S_ISREG(st.st_mode) && + st.st_size > 0); +} + +static int condition_test_file_is_executable(Condition *c) { + struct stat st; + + assert(c); + assert(c->parameter); + assert(c->type == CONDITION_FILE_IS_EXECUTABLE); + + return (stat(c->parameter, &st) >= 0 && + S_ISREG(st.st_mode) && + (st.st_mode & 0111)); +} + +static int condition_test_null(Condition *c) { + assert(c); + assert(c->type == CONDITION_NULL); + + /* Note that during parsing we already evaluate the string and + * store it in c->negate */ + return true; +} + +int condition_test(Condition *c) { + + static int (*const condition_tests[_CONDITION_TYPE_MAX])(Condition *c) = { + [CONDITION_PATH_EXISTS] = condition_test_path_exists, + [CONDITION_PATH_EXISTS_GLOB] = condition_test_path_exists_glob, + [CONDITION_PATH_IS_DIRECTORY] = condition_test_path_is_directory, + [CONDITION_PATH_IS_SYMBOLIC_LINK] = condition_test_path_is_symbolic_link, + [CONDITION_PATH_IS_MOUNT_POINT] = condition_test_path_is_mount_point, + [CONDITION_PATH_IS_READ_WRITE] = condition_test_path_is_read_write, + [CONDITION_DIRECTORY_NOT_EMPTY] = condition_test_directory_not_empty, + [CONDITION_FILE_NOT_EMPTY] = condition_test_file_not_empty, + [CONDITION_FILE_IS_EXECUTABLE] = condition_test_file_is_executable, + [CONDITION_KERNEL_COMMAND_LINE] = condition_test_kernel_command_line, + [CONDITION_KERNEL_VERSION] = condition_test_kernel_version, + [CONDITION_VIRTUALIZATION] = condition_test_virtualization, + [CONDITION_SECURITY] = condition_test_security, + [CONDITION_CAPABILITY] = condition_test_capability, + [CONDITION_HOST] = condition_test_host, + [CONDITION_AC_POWER] = condition_test_ac_power, + [CONDITION_ARCHITECTURE] = condition_test_architecture, + [CONDITION_NEEDS_UPDATE] = condition_test_needs_update, + [CONDITION_FIRST_BOOT] = condition_test_first_boot, + [CONDITION_USER] = condition_test_user, + [CONDITION_GROUP] = condition_test_group, + [CONDITION_CONTROL_GROUP_CONTROLLER] = condition_test_control_group_controller, + [CONDITION_NULL] = condition_test_null, + }; + + int r, b; + + assert(c); + assert(c->type >= 0); + assert(c->type < _CONDITION_TYPE_MAX); + + r = condition_tests[c->type](c); + if (r < 0) { + c->result = CONDITION_ERROR; + return r; + } + + b = (r > 0) == !c->negate; + c->result = b ? CONDITION_SUCCEEDED : CONDITION_FAILED; + return b; +} + +void condition_dump(Condition *c, FILE *f, const char *prefix, const char *(*to_string)(ConditionType t)) { + assert(c); + assert(f); + + prefix = strempty(prefix); + + fprintf(f, + "%s\t%s: %s%s%s %s\n", + prefix, + to_string(c->type), + c->trigger ? "|" : "", + c->negate ? "!" : "", + c->parameter, + condition_result_to_string(c->result)); +} + +void condition_dump_list(Condition *first, FILE *f, const char *prefix, const char *(*to_string)(ConditionType t)) { + Condition *c; + + LIST_FOREACH(conditions, c, first) + condition_dump(c, f, prefix, to_string); +} + +static const char* const condition_type_table[_CONDITION_TYPE_MAX] = { + [CONDITION_ARCHITECTURE] = "ConditionArchitecture", + [CONDITION_VIRTUALIZATION] = "ConditionVirtualization", + [CONDITION_HOST] = "ConditionHost", + [CONDITION_KERNEL_COMMAND_LINE] = "ConditionKernelCommandLine", + [CONDITION_KERNEL_VERSION] = "ConditionKernelVersion", + [CONDITION_SECURITY] = "ConditionSecurity", + [CONDITION_CAPABILITY] = "ConditionCapability", + [CONDITION_AC_POWER] = "ConditionACPower", + [CONDITION_NEEDS_UPDATE] = "ConditionNeedsUpdate", + [CONDITION_FIRST_BOOT] = "ConditionFirstBoot", + [CONDITION_PATH_EXISTS] = "ConditionPathExists", + [CONDITION_PATH_EXISTS_GLOB] = "ConditionPathExistsGlob", + [CONDITION_PATH_IS_DIRECTORY] = "ConditionPathIsDirectory", + [CONDITION_PATH_IS_SYMBOLIC_LINK] = "ConditionPathIsSymbolicLink", + [CONDITION_PATH_IS_MOUNT_POINT] = "ConditionPathIsMountPoint", + [CONDITION_PATH_IS_READ_WRITE] = "ConditionPathIsReadWrite", + [CONDITION_DIRECTORY_NOT_EMPTY] = "ConditionDirectoryNotEmpty", + [CONDITION_FILE_NOT_EMPTY] = "ConditionFileNotEmpty", + [CONDITION_FILE_IS_EXECUTABLE] = "ConditionFileIsExecutable", + [CONDITION_USER] = "ConditionUser", + [CONDITION_GROUP] = "ConditionGroup", + [CONDITION_CONTROL_GROUP_CONTROLLER] = "ConditionControlGroupController", + [CONDITION_NULL] = "ConditionNull" +}; + +DEFINE_STRING_TABLE_LOOKUP(condition_type, ConditionType); + +static const char* const assert_type_table[_CONDITION_TYPE_MAX] = { + [CONDITION_ARCHITECTURE] = "AssertArchitecture", + [CONDITION_VIRTUALIZATION] = "AssertVirtualization", + [CONDITION_HOST] = "AssertHost", + [CONDITION_KERNEL_COMMAND_LINE] = "AssertKernelCommandLine", + [CONDITION_KERNEL_VERSION] = "AssertKernelVersion", + [CONDITION_SECURITY] = "AssertSecurity", + [CONDITION_CAPABILITY] = "AssertCapability", + [CONDITION_AC_POWER] = "AssertACPower", + [CONDITION_NEEDS_UPDATE] = "AssertNeedsUpdate", + [CONDITION_FIRST_BOOT] = "AssertFirstBoot", + [CONDITION_PATH_EXISTS] = "AssertPathExists", + [CONDITION_PATH_EXISTS_GLOB] = "AssertPathExistsGlob", + [CONDITION_PATH_IS_DIRECTORY] = "AssertPathIsDirectory", + [CONDITION_PATH_IS_SYMBOLIC_LINK] = "AssertPathIsSymbolicLink", + [CONDITION_PATH_IS_MOUNT_POINT] = "AssertPathIsMountPoint", + [CONDITION_PATH_IS_READ_WRITE] = "AssertPathIsReadWrite", + [CONDITION_DIRECTORY_NOT_EMPTY] = "AssertDirectoryNotEmpty", + [CONDITION_FILE_NOT_EMPTY] = "AssertFileNotEmpty", + [CONDITION_FILE_IS_EXECUTABLE] = "AssertFileIsExecutable", + [CONDITION_USER] = "AssertUser", + [CONDITION_GROUP] = "AssertGroup", + [CONDITION_CONTROL_GROUP_CONTROLLER] = "AssertControlGroupController", + [CONDITION_NULL] = "AssertNull" +}; + +DEFINE_STRING_TABLE_LOOKUP(assert_type, ConditionType); + +static const char* const condition_result_table[_CONDITION_RESULT_MAX] = { + [CONDITION_UNTESTED] = "untested", + [CONDITION_SUCCEEDED] = "succeeded", + [CONDITION_FAILED] = "failed", + [CONDITION_ERROR] = "error", +}; + +DEFINE_STRING_TABLE_LOOKUP(condition_result, ConditionResult); |