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tmpfiles: port from dirname/basename to path_extract_directory/filename()

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let's use our better, newer internal APIs for these purposes. This gets us
two things: safer handling when the root dir is specified, and better
handling of paths with trailing slashes, as we can refuse them whenever
a directory is not acceptable.
This commit is contained in:
Lennart Poettering 2022-07-08 00:15:09 +02:00
parent 70980a39b8
commit 4609d3bb07
1 changed files with 76 additions and 52 deletions
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128
src/tmpfiles/tmpfiles.c
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@ -930,20 +930,20 @@ static int path_open_parent_safe(const char *path) {
_cleanup_free_ char *dn = NULL;
int r, fd;
if (path_equal(path, "/") || !path_is_normalized(path))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Failed to open parent of '%s': invalid path.",
path);
if (!path_is_normalized(path))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to open parent of '%s': path not normalized.", path);
dn = dirname_malloc(path);
if (!dn)
return log_oom();
r = path_extract_directory(path, &dn);
if (r < 0)
return log_error_errno(r, "Unable to determine parent directory of '%s': %m", path);
r = chase_symlinks(dn, arg_root, CHASE_SAFE|CHASE_WARN, NULL, &fd);
if (r < 0 && r != -ENOLINK)
return log_error_errno(r, "Failed to validate path %s: %m", path);
if (r == -ENOLINK) /* Unsafe symlink: already covered by CHASE_WARN */
return r;
if (r < 0)
return log_error_errno(r, "Failed to open path '%s': %m", dn);
return r < 0 ? r : fd;
return fd;
}
static int path_open_safe(const char *path) {
@ -956,15 +956,15 @@ static int path_open_safe(const char *path) {
assert(path);
if (!path_is_normalized(path))
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
"Failed to open invalid path '%s'.",
path);
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to open invalid path '%s'.", path);
r = chase_symlinks(path, arg_root, CHASE_SAFE|CHASE_WARN|CHASE_NOFOLLOW, NULL, &fd);
if (r < 0 && r != -ENOLINK)
return log_error_errno(r, "Failed to validate path %s: %m", path);
if (r == -ENOLINK)
return r; /* Unsafe symlink: already covered by CHASE_WARN */
if (r < 0)
return log_error_errno(r, "Failed to open path %s: %m", path);
return r < 0 ? r : fd;
return fd;
}
static int path_set_perms(Item *i, const char *path) {
@ -1331,7 +1331,7 @@ static int path_set_attribute(Item *item, const char *path) {
static int write_one_file(Item *i, const char *path) {
_cleanup_close_ int fd = -1, dir_fd = -1;
char *bn;
_cleanup_free_ char *bn = NULL;
int r;
assert(i);
@ -1339,14 +1339,18 @@ static int write_one_file(Item *i, const char *path) {
assert(i->argument);
assert(i->type == WRITE_FILE);
/* Validate the path and keep the fd on the directory for opening the
* file so we're sure that it can't be changed behind our back. */
r = path_extract_filename(path, &bn);
if (r < 0)
return log_error_errno(r, "Failed to extract filename from path '%s': %m", path);
if (r == O_DIRECTORY)
return log_error_errno(SYNTHETIC_ERRNO(EISDIR), "Cannot open path '%s' for writing, is a directory.", path);
/* Validate the path and keep the fd on the directory for opening the file so we're sure that it
* can't be changed behind our back. */
dir_fd = path_open_parent_safe(path);
if (dir_fd < 0)
return dir_fd;
bn = basename(path);
/* Follows symlinks */
fd = openat(dir_fd, bn,
O_NONBLOCK|O_CLOEXEC|O_WRONLY|O_NOCTTY|(i->append_or_force ? O_APPEND : 0),
@ -1375,9 +1379,9 @@ static int write_one_file(Item *i, const char *path) {
static int create_file(Item *i, const char *path) {
_cleanup_close_ int fd = -1, dir_fd = -1;
_cleanup_free_ char *bn = NULL;
struct stat stbuf, *st = NULL;
int r = 0;
char *bn;
assert(i);
assert(path);
@ -1385,14 +1389,18 @@ static int create_file(Item *i, const char *path) {
/* 'f' operates on regular files exclusively. */
/* Validate the path and keep the fd on the directory for opening the
* file so we're sure that it can't be changed behind our back. */
r = path_extract_filename(path, &bn);
if (r < 0)
return log_error_errno(r, "Failed to extract filename from path '%s': %m", path);
if (r == O_DIRECTORY)
return log_error_errno(SYNTHETIC_ERRNO(EISDIR), "Cannot open path '%s' for writing, is a directory.", path);
/* Validate the path and keep the fd on the directory for opening the file so we're sure that it
* can't be changed behind our back. */
dir_fd = path_open_parent_safe(path);
if (dir_fd < 0)
return dir_fd;
bn = basename(path);
RUN_WITH_UMASK(0000) {
mac_selinux_create_file_prepare(path, S_IFREG);
fd = openat(dir_fd, bn, O_CREAT|O_EXCL|O_NOFOLLOW|O_NONBLOCK|O_CLOEXEC|O_WRONLY|O_NOCTTY, i->mode);
@ -1442,28 +1450,31 @@ static int create_file(Item *i, const char *path) {
static int truncate_file(Item *i, const char *path) {
_cleanup_close_ int fd = -1, dir_fd = -1;
_cleanup_free_ char *bn = NULL;
struct stat stbuf, *st = NULL;
bool erofs = false;
int r = 0;
char *bn;
assert(i);
assert(path);
assert(i->type == TRUNCATE_FILE || (i->type == CREATE_FILE && i->append_or_force));
/* We want to operate on regular file exclusively especially since
* O_TRUNC is unspecified if the file is neither a regular file nor a
* fifo nor a terminal device. Therefore we first open the file and make
* sure it's a regular one before truncating it. */
/* We want to operate on regular file exclusively especially since O_TRUNC is unspecified if the file
* is neither a regular file nor a fifo nor a terminal device. Therefore we first open the file and
* make sure it's a regular one before truncating it. */
/* Validate the path and keep the fd on the directory for opening the
* file so we're sure that it can't be changed behind our back. */
r = path_extract_filename(path, &bn);
if (r < 0)
return log_error_errno(r, "Failed to extract filename from path '%s': %m", path);
if (r == O_DIRECTORY)
return log_error_errno(SYNTHETIC_ERRNO(EISDIR), "Cannot open path '%s' for truncation, is a directory.", path);
/* Validate the path and keep the fd on the directory for opening the file so we're sure that it
* can't be changed behind our back. */
dir_fd = path_open_parent_safe(path);
if (dir_fd < 0)
return dir_fd;
bn = basename(path);
RUN_WITH_UMASK(0000) {
mac_selinux_create_file_prepare(path, S_IFREG);
fd = openat(dir_fd, bn, O_CREAT|O_NOFOLLOW|O_NONBLOCK|O_CLOEXEC|O_WRONLY|O_NOCTTY, i->mode);
@ -1526,16 +1537,17 @@ static int truncate_file(Item *i, const char *path) {
static int copy_files(Item *i) {
_cleanup_close_ int dfd = -1, fd = -1;
char *bn;
_cleanup_free_ char *bn = NULL;
int r;
log_debug("Copying tree \"%s\" to \"%s\".", i->argument, i->path);
bn = basename(i->path);
r = path_extract_filename(i->path, &bn);
if (r < 0)
return log_error_errno(r, "Failed to extract filename from path '%s': %m", i->path);
/* Validate the path and use the returned directory fd for copying the
* target so we're sure that the path can't be changed behind our
* back. */
/* Validate the path and use the returned directory fd for copying the target so we're sure that the
* path can't be changed behind our back. */
dfd = path_open_parent_safe(i->path);
if (dfd < 0)
return dfd;
@ -1593,6 +1605,7 @@ static const char *const creation_mode_verb_table[_CREATION_MODE_MAX] = {
DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(creation_mode_verb, CreationMode);
static int create_directory_or_subvolume(const char *path, mode_t mode, bool subvol, CreationMode *creation) {
_cleanup_free_ char *bn = NULL;
_cleanup_close_ int pfd = -1;
CreationMode c;
int r;
@ -1602,6 +1615,10 @@ static int create_directory_or_subvolume(const char *path, mode_t mode, bool sub
if (!creation)
creation = &c;
r = path_extract_filename(path, &bn);
if (r < 0)
return log_error_errno(r, "Failed to extract filename from path '%s': %m", path);
pfd = path_open_parent_safe(path);
if (pfd < 0)
return pfd;
@ -1627,14 +1644,14 @@ static int create_directory_or_subvolume(const char *path, mode_t mode, bool sub
subvol = false;
else {
RUN_WITH_UMASK((~mode) & 0777)
r = btrfs_subvol_make_fd(pfd, basename(path));
r = btrfs_subvol_make_fd(pfd, bn);
}
} else
r = 0;
if (!subvol || r == -ENOTTY)
RUN_WITH_UMASK(0000)
r = mkdirat_label(pfd, basename(path), mode);
r = mkdirat_label(pfd, bn, mode);
if (r < 0) {
int k;
@ -1657,9 +1674,9 @@ static int create_directory_or_subvolume(const char *path, mode_t mode, bool sub
log_debug("%s directory \"%s\".", creation_mode_verb_to_string(*creation), path);
r = openat(pfd, basename(path), O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
r = openat(pfd, bn, O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
if (r < 0)
return log_error_errno(errno, "Failed to open directory '%s': %m", basename(path));
return log_error_errno(errno, "Failed to open directory '%s': %m", bn);
return r;
}
@ -1742,18 +1759,21 @@ static int empty_directory(Item *i, const char *path) {
static int create_device(Item *i, mode_t file_type) {
_cleanup_close_ int dfd = -1, fd = -1;
_cleanup_free_ char *bn = NULL;
CreationMode creation;
char *bn;
int r;
assert(i);
assert(IN_SET(file_type, S_IFBLK, S_IFCHR));
bn = basename(i->path);
r = path_extract_filename(i->path, &bn);
if (r < 0)
return log_error_errno(r, "Failed to extract filename from path '%s': %m", i->path);
if (r == O_DIRECTORY)
return log_error_errno(SYNTHETIC_ERRNO(EISDIR), "Cannot open path '%s' for creating device node, is a directory.", i->path);
/* Validate the path and use the returned directory fd for copying the
* target so we're sure that the path can't be changed behind our
* back. */
/* Validate the path and use the returned directory fd for copying the target so we're sure that the
* path can't be changed behind our back. */
dfd = path_open_parent_safe(i->path);
if (dfd < 0)
return dfd;
@ -1816,17 +1836,21 @@ static int create_device(Item *i, mode_t file_type) {
static int create_fifo(Item *i, const char *path) {
_cleanup_close_ int pfd = -1, fd = -1;
_cleanup_free_ char *bn = NULL;
CreationMode creation;
struct stat st;
char *bn;
int r;
r = path_extract_filename(i->path, &bn);
if (r < 0)
return log_error_errno(r, "Failed to extract filename from path '%s': %m", path);
if (r == O_DIRECTORY)
return log_error_errno(SYNTHETIC_ERRNO(EISDIR), "Cannot open path '%s' for creating FIFO, is a directory.", path);
pfd = path_open_parent_safe(path);
if (pfd < 0)
return pfd;
bn = basename(path);
RUN_WITH_UMASK(0000) {
mac_selinux_create_file_prepare(path, S_IFIFO);
r = mkfifoat(pfd, bn, i->mode);