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fs-util: beef up chmod_and_chown() a bit

This commit is contained in:
Lennart Poettering 2018-07-24 17:12:27 +02:00
parent d739169804
commit de321f5228
1 changed files with 40 additions and 10 deletions
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50
src/basic/fs-util.c
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@ -211,31 +211,62 @@ int readlink_and_make_absolute(const char *p, char **r) {
}
int chmod_and_chown(const char *path, mode_t mode, uid_t uid, gid_t gid) {
char fd_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
_cleanup_close_ int fd = -1;
assert(path);
/* Under the assumption that we are running privileged we
* first change the access mode and only then hand out
/* Under the assumption that we are running privileged we first change the access mode and only then hand out
* ownership to avoid a window where access is too open. */
if (mode != MODE_INVALID)
if (chmod(path, mode) < 0)
fd = open(path, O_PATH|O_CLOEXEC|O_NOFOLLOW); /* Let's acquire an O_PATH fd, as precaution to change mode/owner
* on the same file */
if (fd < 0)
return -errno;
xsprintf(fd_path, "/proc/self/fd/%i", fd);
if (mode != MODE_INVALID) {
if ((mode & S_IFMT) != 0) {
struct stat st;
if (stat(fd_path, &st) < 0)
return -errno;
if ((mode & S_IFMT) != (st.st_mode & S_IFMT))
return -EINVAL;
}
if (chmod(fd_path, mode & 07777) < 0)
return -errno;
}
if (uid != UID_INVALID || gid != GID_INVALID)
if (chown(path, uid, gid) < 0)
if (chown(fd_path, uid, gid) < 0)
return -errno;
return 0;
}
int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid) {
/* Under the assumption that we are running privileged we
* first change the access mode and only then hand out
/* Under the assumption that we are running privileged we first change the access mode and only then hand out
* ownership to avoid a window where access is too open. */
if (mode != MODE_INVALID)
if (fchmod(fd, mode) < 0)
if (mode != MODE_INVALID) {
if ((mode & S_IFMT) != 0) {
struct stat st;
if (fstat(fd, &st) < 0)
return -errno;
if ((mode & S_IFMT) != (st.st_mode & S_IFMT))
return -EINVAL;
}
if (fchmod(fd, mode & 0777) < 0)
return -errno;
}
if (uid != UID_INVALID || gid != GID_INVALID)
if (fchown(fd, uid, gid) < 0)
@ -263,7 +294,6 @@ int fchmod_opath(int fd, mode_t m) {
* fchownat() does. */
xsprintf(procfs_path, "/proc/self/fd/%i", fd);
if (chmod(procfs_path, m) < 0)
return -errno;