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shadow/libmisc/copydir.c

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/*
* SPDX-FileCopyrightText: 1991 - 1994, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 2001, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2003 - 2006, Tomasz Kłoczko
* SPDX-FileCopyrightText: 2007 - 2010, Nicolas François
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <config.h>
#ident "$Id$"
#include <assert.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <fcntl.h>
#include <stdio.h>
#include "prototypes.h"
#include "defines.h"
#ifdef WITH_SELINUX
#include <selinux/selinux.h>
#endif /* WITH_SELINUX */
#if defined(WITH_ACL) || defined(WITH_ATTR)
#include <stdarg.h>
#include <attr/error_context.h>
#endif /* WITH_ACL || WITH_ATTR */
#ifdef WITH_ACL
#include <acl/libacl.h>
#endif /* WITH_ACL */
#ifdef WITH_ATTR
#include <attr/libattr.h>
#endif /* WITH_ATTR */
static /*@null@*/const char *src_orig;
static /*@null@*/const char *dst_orig;
struct link_name {
dev_t ln_dev;
ino_t ln_ino;
nlink_t ln_count;
char *ln_name;
/*@dependent@*/struct link_name *ln_next;
};
static /*@exposed@*/struct link_name *links;
static int copy_entry (const char *src, const char *dst,
bool reset_selinux,
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
static int copy_dir (const char *src, const char *dst,
bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
#ifdef S_IFLNK
static /*@null@*/char *readlink_malloc (const char *filename);
static int copy_symlink (const char *src, const char *dst,
unused bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
#endif /* S_IFLNK */
static int copy_hardlink (const char *dst,
unused bool reset_selinux,
struct link_name *lp);
static int copy_special (const char *src, const char *dst,
bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
static int copy_file (const char *src, const char *dst,
bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
static int chown_if_needed (const char *dst, const struct stat *statp,
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
static int lchown_if_needed (const char *dst, const struct stat *statp,
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
static int fchown_if_needed (int fdst, const struct stat *statp,
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid);
#if defined(WITH_ACL) || defined(WITH_ATTR)
/*
* error_acl - format the error messages for the ACL and EQ libraries.
*/
static void error_acl (struct error_context *ctx, const char *fmt, ...)
{
va_list ap;
/* ignore the case when destination does not support ACLs
* or extended attributes */
if (ENOTSUP == errno) {
errno = 0;
return;
}
va_start (ap, fmt);
(void) fprintf (shadow_logfd, _("%s: "), Prog);
if (vfprintf (shadow_logfd, fmt, ap) != 0) {
(void) fputs (_(": "), shadow_logfd);
}
(void) fprintf (shadow_logfd, "%s\n", strerror (errno));
va_end (ap);
}
static struct error_context ctx = {
error_acl
};
#endif /* WITH_ACL || WITH_ATTR */
/*
* remove_link - delete a link from the linked list
*/
static void remove_link (/*@only@*/struct link_name *ln)
{
struct link_name *lp;
if (links == ln) {
links = ln->ln_next;
free (ln->ln_name);
free (ln);
return;
}
for (lp = links; NULL !=lp; lp = lp->ln_next) {
if (lp->ln_next == ln) {
break;
}
}
if (NULL == lp) {
free (ln->ln_name);
free (ln);
return;
}
lp->ln_next = lp->ln_next->ln_next;
free (ln->ln_name);
free (ln);
}
/*
* check_link - see if a file is really a link
*/
static /*@exposed@*/ /*@null@*/struct link_name *check_link (const char *name, const struct stat *sb)
{
struct link_name *lp;
size_t src_len;
size_t dst_len;
size_t name_len;
size_t len;
/* copy_tree () must be the entry point */
assert (NULL != src_orig);
assert (NULL != dst_orig);
for (lp = links; NULL != lp; lp = lp->ln_next) {
if ((lp->ln_dev == sb->st_dev) && (lp->ln_ino == sb->st_ino)) {
return lp;
}
}
if (sb->st_nlink == 1) {
return NULL;
}
lp = (struct link_name *) xmalloc (sizeof *lp);
src_len = strlen (src_orig);
dst_len = strlen (dst_orig);
name_len = strlen (name);
lp->ln_dev = sb->st_dev;
lp->ln_ino = sb->st_ino;
lp->ln_count = sb->st_nlink;
len = name_len - src_len + dst_len + 1;
lp->ln_name = (char *) xmalloc (len);
(void) snprintf (lp->ln_name, len, "%s%s", dst_orig, name + src_len);
lp->ln_next = links;
links = lp;
return NULL;
}
/*
* copy_tree - copy files in a directory tree
*
* copy_tree() walks a directory tree and copies ordinary files
* as it goes.
*
* When reset_selinux is enabled, extended attributes (and thus
* SELinux attributes) are not copied.
*
* old_uid and new_uid are used to set the ownership of the copied
* files. Unless old_uid is set to -1, only the files owned by
* old_uid have their ownership changed to new_uid. In addition, if
* new_uid is set to -1, no ownership will be changed.
*
* The same logic applies for the group-ownership and
* old_gid/new_gid.
*/
int copy_tree (const char *src_root, const char *dst_root,
bool copy_root, bool reset_selinux,
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid)
{
int err = 0;
bool set_orig = false;
struct DIRECT *ent;
DIR *dir;
if (copy_root) {
struct stat sb;
if (access (dst_root, F_OK) == 0) {
return -1;
}
if (LSTAT (src_root, &sb) == -1) {
return -1;
}
if (!S_ISDIR (sb.st_mode)) {
fprintf (shadow_logfd,
"%s: %s is not a directory",
Prog, src_root);
return -1;
}
return copy_entry (src_root, dst_root, reset_selinux,
old_uid, new_uid, old_gid, new_gid);
}
/*
* Make certain both directories exist. This routine is called
* after the home directory is created, or recursively after the
* target is created. It assumes the target directory exists.
*/
if ( (access (src_root, F_OK) != 0)
|| (access (dst_root, F_OK) != 0)) {
return -1;
}
/*
* Open the source directory and read each entry. Every file
* entry in the directory is copied with the UID and GID set
* to the provided values. As an added security feature only
* regular files (and directories ...) are copied, and no file
* is made set-ID.
*/
dir = opendir (src_root);
if (NULL == dir) {
return -1;
}
if (src_orig == NULL) {
src_orig = src_root;
dst_orig = dst_root;
set_orig = true;
}
while ((0 == err) && (ent = readdir (dir)) != NULL) {
/*
* Skip the "." and ".." entries
*/
if ((strcmp (ent->d_name, ".") != 0) &&
(strcmp (ent->d_name, "..") != 0)) {
char *src_name;
char *dst_name;
size_t src_len = strlen (ent->d_name) + 2;
size_t dst_len = strlen (ent->d_name) + 2;
src_len += strlen (src_root);
dst_len += strlen (dst_root);
src_name = (char *) malloc (src_len);
dst_name = (char *) malloc (dst_len);
if ((NULL == src_name) || (NULL == dst_name)) {
err = -1;
} else {
/*
* Build the filename for both the source and
* the destination files.
*/
(void) snprintf (src_name, src_len, "%s/%s",
src_root, ent->d_name);
(void) snprintf (dst_name, dst_len, "%s/%s",
dst_root, ent->d_name);
err = copy_entry (src_name, dst_name,
reset_selinux,
old_uid, new_uid,
old_gid, new_gid);
}
if (NULL != src_name) {
free (src_name);
}
if (NULL != dst_name) {
free (dst_name);
}
}
}
(void) closedir (dir);
if (set_orig) {
src_orig = NULL;
dst_orig = NULL;
/* FIXME: clean links
* Since there can be hardlinks elsewhere on the device,
* we cannot check that all the hardlinks were found:
assert (NULL == links);
*/
}
#ifdef WITH_SELINUX
/* Reset SELinux to create files with default contexts.
* Note that the context is only reset on exit of copy_tree (it is
* assumed that the program would quit without needing a restored
* context if copy_tree failed previously), and that copy_tree can
* be called recursively (hence the context is set on the
* sub-functions of copy_entry).
*/
if (reset_selinux_file_context () != 0) {
err = -1;
}
#endif /* WITH_SELINUX */
return err;
}
/*
* copy_entry - copy the entry of a directory
*
* Copy the entry src to dst.
* Depending on the type of entry, this function will forward the
* request to copy_dir(), copy_symlink(), copy_hardlink(),
* copy_special(), or copy_file().
*
* The access and modification time will not be modified.
*
* The permissions will be set to new_uid/new_gid.
*
* If new_uid (resp. new_gid) is equal to -1, the user (resp. group) will
* not be modified.
*
* Only the files owned (resp. group-owned) by old_uid (resp.
* old_gid) will be modified, unless old_uid (resp. old_gid) is set
* to -1.
*/
static int copy_entry (const char *src, const char *dst,
bool reset_selinux,
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid)
{
int err = 0;
struct stat sb;
struct link_name *lp;
struct timeval mt[2];
if (LSTAT (src, &sb) == -1) {
/* If we cannot stat the file, do not care. */
} else {
#ifdef HAVE_STRUCT_STAT_ST_ATIM
mt[0].tv_sec = sb.st_atim.tv_sec;
mt[0].tv_usec = sb.st_atim.tv_nsec / 1000;
#else /* !HAVE_STRUCT_STAT_ST_ATIM */
mt[0].tv_sec = sb.st_atime;
# ifdef HAVE_STRUCT_STAT_ST_ATIMENSEC
mt[0].tv_usec = sb.st_atimensec / 1000;
# else /* !HAVE_STRUCT_STAT_ST_ATIMENSEC */
mt[0].tv_usec = 0;
# endif /* !HAVE_STRUCT_STAT_ST_ATIMENSEC */
#endif /* !HAVE_STRUCT_STAT_ST_ATIM */
#ifdef HAVE_STRUCT_STAT_ST_MTIM
mt[1].tv_sec = sb.st_mtim.tv_sec;
mt[1].tv_usec = sb.st_mtim.tv_nsec / 1000;
#else /* !HAVE_STRUCT_STAT_ST_MTIM */
mt[1].tv_sec = sb.st_mtime;
# ifdef HAVE_STRUCT_STAT_ST_MTIMENSEC
mt[1].tv_usec = sb.st_mtimensec / 1000;
# else /* !HAVE_STRUCT_STAT_ST_MTIMENSEC */
mt[1].tv_usec = 0;
# endif /* !HAVE_STRUCT_STAT_ST_MTIMENSEC */
#endif /* !HAVE_STRUCT_STAT_ST_MTIM */
if (S_ISDIR (sb.st_mode)) {
err = copy_dir (src, dst, reset_selinux, &sb, mt,
old_uid, new_uid, old_gid, new_gid);
}
#ifdef S_IFLNK
/*
* Copy any symbolic links
*/
else if (S_ISLNK (sb.st_mode)) {
err = copy_symlink (src, dst, reset_selinux, &sb, mt,
old_uid, new_uid, old_gid, new_gid);
}
#endif /* S_IFLNK */
/*
* See if this is a previously copied link
*/
else if ((lp = check_link (src, &sb)) != NULL) {
err = copy_hardlink (dst, reset_selinux, lp);
}
/*
* Deal with FIFOs and special files. The user really
* shouldn't have any of these, but it seems like it
* would be nice to copy everything ...
*/
else if (!S_ISREG (sb.st_mode)) {
err = copy_special (src, dst, reset_selinux, &sb, mt,
old_uid, new_uid, old_gid, new_gid);
}
/*
* Create the new file and copy the contents. The new
* file will be owned by the provided UID and GID values.
*/
else {
err = copy_file (src, dst, reset_selinux, &sb, mt,
old_uid, new_uid, old_gid, new_gid);
}
}
return err;
}
/*
* copy_dir - copy a directory
*
* Copy a directory (recursively) from src to dst.
*
* statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
* the access and modification and the access rights.
*
* Return 0 on success, -1 on error.
*/
static int copy_dir (const char *src, const char *dst,
bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid)
{
int err = 0;
/*
* Create a new target directory, make it owned by
* the user and then recursively copy that directory.
*/
#ifdef WITH_SELINUX
if (set_selinux_file_context (dst, S_IFDIR) != 0) {
return -1;
}
#endif /* WITH_SELINUX */
if ( (mkdir (dst, statp->st_mode) != 0)
|| (chown_if_needed (dst, statp,
old_uid, new_uid, old_gid, new_gid) != 0)
#ifdef WITH_ACL
|| ( (perm_copy_file (src, dst, &ctx) != 0)
&& (errno != 0))
#else /* !WITH_ACL */
|| (chmod (dst, statp->st_mode) != 0)
#endif /* !WITH_ACL */
#ifdef WITH_ATTR
/*
* If the third parameter is NULL, all extended attributes
* except those that define Access Control Lists are copied.
* ACLs are excluded by default because copying them between
* file systems with and without ACL support needs some
* additional logic so that no unexpected permissions result.
*/
|| ( !reset_selinux
&& (attr_copy_file (src, dst, NULL, &ctx) != 0)
&& (errno != 0))
#endif /* WITH_ATTR */
|| (copy_tree (src, dst, false, reset_selinux,
old_uid, new_uid, old_gid, new_gid) != 0)
|| (utimes (dst, mt) != 0)) {
err = -1;
}
return err;
}
#ifdef S_IFLNK
/*
* readlink_malloc - wrapper for readlink
*
* return NULL on error.
* The return string shall be freed by the caller.
*/
static /*@null@*/char *readlink_malloc (const char *filename)
{
size_t size = 1024;
while (true) {
ssize_t nchars;
char *buffer = (char *) malloc (size);
if (NULL == buffer) {
return NULL;
}
nchars = readlink (filename, buffer, size);
if (nchars < 0) {
free(buffer);
return NULL;
}
if ((size_t) nchars < size) { /* The buffer was large enough */
/* readlink does not nul-terminate */
buffer[nchars] = '\0';
return buffer;
}
/* Try again with a bigger buffer */
free (buffer);
size *= 2;
}
}
/*
* copy_symlink - copy a symlink
*
* Copy a symlink from src to dst.
*
* statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
* the access and modification and the access rights.
*
* Return 0 on success, -1 on error.
*/
static int copy_symlink (const char *src, const char *dst,
unused bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid)
{
char *oldlink;
/* copy_tree () must be the entry point */
assert (NULL != src_orig);
assert (NULL != dst_orig);
/*
* Get the name of the file which the link points
* to. If that name begins with the original
* source directory name, that part of the link
* name will be replaced with the original
* destination directory name.
*/
oldlink = readlink_malloc (src);
if (NULL == oldlink) {
return -1;
}
/* If src was a link to an entry of the src_orig directory itself,
* create a link to the corresponding entry in the dst_orig
* directory.
*/
if (strncmp (oldlink, src_orig, strlen (src_orig)) == 0) {
size_t len = strlen (dst_orig) + strlen (oldlink) - strlen (src_orig) + 1;
char *dummy = (char *) xmalloc (len);
(void) snprintf (dummy, len, "%s%s",
dst_orig,
oldlink + strlen (src_orig));
free (oldlink);
oldlink = dummy;
}
#ifdef WITH_SELINUX
if (set_selinux_file_context (dst, S_IFLNK) != 0) {
free (oldlink);
return -1;
}
#endif /* WITH_SELINUX */
if ( (symlink (oldlink, dst) != 0)
|| (lchown_if_needed (dst, statp,
old_uid, new_uid, old_gid, new_gid) != 0)) {
/* FIXME: there are no modes on symlinks, right?
* ACL could be copied, but this would be much more
* complex than calling perm_copy_file.
* Ditto for Extended Attributes.
* We currently only document that ACL and Extended
* Attributes are not copied.
*/
free (oldlink);
return -1;
}
free (oldlink);
#ifdef HAVE_LUTIMES
/* 2007-10-18: We don't care about
* exit status of lutimes because
* it returns ENOSYS on many system
* - not implemented
*/
(void) lutimes (dst, mt);
#endif /* HAVE_LUTIMES */
return 0;
}
#endif /* S_IFLNK */
/*
* copy_hardlink - copy a hardlink
*
* Copy a hardlink from src to dst.
*
* Return 0 on success, -1 on error.
*/
static int copy_hardlink (const char *dst,
unused bool reset_selinux,
struct link_name *lp)
{
/* FIXME: selinux, ACL, Extended Attributes needed? */
if (link (lp->ln_name, dst) != 0) {
return -1;
}
/* If the file could be unlinked, decrement the links counter,
* and forget about this link if it was the last reference */
lp->ln_count--;
if (lp->ln_count <= 0) {
remove_link (lp);
}
return 0;
}
/*
* copy_special - copy a special file
*
* Copy a special file from src to dst.
*
* statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
* the access and modification and the access rights.
*
* Return 0 on success, -1 on error.
*/
static int copy_special (const char *src, const char *dst,
bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid)
{
int err = 0;
#ifdef WITH_SELINUX
if (set_selinux_file_context (dst, statp->st_mode & S_IFMT) != 0) {
return -1;
}
#endif /* WITH_SELINUX */
if ( (mknod (dst, statp->st_mode & ~07777, statp->st_rdev) != 0)
|| (chown_if_needed (dst, statp,
old_uid, new_uid, old_gid, new_gid) != 0)
#ifdef WITH_ACL
|| ( (perm_copy_file (src, dst, &ctx) != 0)
&& (errno != 0))
#else /* !WITH_ACL */
|| (chmod (dst, statp->st_mode & 07777) != 0)
#endif /* !WITH_ACL */
#ifdef WITH_ATTR
/*
* If the third parameter is NULL, all extended attributes
* except those that define Access Control Lists are copied.
* ACLs are excluded by default because copying them between
* file systems with and without ACL support needs some
* additional logic so that no unexpected permissions result.
*/
|| ( !reset_selinux
&& (attr_copy_file (src, dst, NULL, &ctx) != 0)
&& (errno != 0))
#endif /* WITH_ATTR */
|| (utimes (dst, mt) != 0)) {
err = -1;
}
return err;
}
/*
* copy_file - copy a file
*
* Copy a file from src to dst.
*
* statp, mt, old_uid, new_uid, old_gid, and new_gid are used to set
* the access and modification and the access rights.
*
* Return 0 on success, -1 on error.
*/
static int copy_file (const char *src, const char *dst,
bool reset_selinux,
const struct stat *statp, const struct timeval mt[],
uid_t old_uid, uid_t new_uid,
gid_t old_gid, gid_t new_gid)
{
int err = 0;
int ifd;
int ofd;
char buf[1024];
ssize_t cnt;
ifd = open (src, O_RDONLY);
if (ifd < 0) {
return -1;
}
#ifdef WITH_SELINUX
if (set_selinux_file_context (dst, S_IFREG) != 0) {
(void) close (ifd);
return -1;
}
#endif /* WITH_SELINUX */
ofd = open (dst, O_WRONLY | O_CREAT | O_TRUNC, statp->st_mode & 07777);
if ( (ofd < 0)
|| (fchown_if_needed (ofd, statp,
old_uid, new_uid, old_gid, new_gid) != 0)
#ifdef WITH_ACL
|| ( (perm_copy_fd (src, ifd, dst, ofd, &ctx) != 0)
&& (errno != 0))
#else /* !WITH_ACL */
|| (fchmod (ofd, statp->st_mode & 07777) != 0)
#endif /* !WITH_ACL */
#ifdef WITH_ATTR
/*
* If the third parameter is NULL, all extended attributes
* except those that define Access Control Lists are copied.
* ACLs are excluded by default because copying them between
* file systems with and without ACL support needs some
* additional logic so that no unexpected permissions result.
*/
|| ( !reset_selinux
&& (attr_copy_fd (src, ifd, dst, ofd, NULL, &ctx) != 0)
&& (errno != 0))
#endif /* WITH_ATTR */
) {
if (ofd >= 0) {
(void) close (ofd);
}
(void) close (ifd);
return -1;
}
while ((cnt = read (ifd, buf, sizeof buf)) > 0) {
if (write (ofd, buf, (size_t)cnt) != cnt) {
(void) close (ofd);
(void) close (ifd);
return -1;
}
}
(void) close (ifd);
#ifdef HAVE_FUTIMES
if (futimes (ofd, mt) != 0) {
(void) close (ofd);
return -1;
}
#endif /* HAVE_FUTIMES */
if (close (ofd) != 0) {
return -1;
}
#ifndef HAVE_FUTIMES
if (utimes(dst, mt) != 0) {
return -1;
}
#endif /* !HAVE_FUTIMES */
return err;
}
#define def_chown_if_needed(chown_function, type_dst) \
static int chown_function ## _if_needed (type_dst dst, \
const struct stat *statp, \
uid_t old_uid, uid_t new_uid, \
gid_t old_gid, gid_t new_gid) \
{ \
uid_t tmpuid = (uid_t) -1; \
gid_t tmpgid = (gid_t) -1; \
\
/* Use new_uid if old_uid is set to -1 or if the file was \
* owned by the user. */ \
if (((uid_t) -1 == old_uid) || (statp->st_uid == old_uid)) { \
tmpuid = new_uid; \
} \
/* Otherwise, or if new_uid was set to -1, we keep the same \
* owner. */ \
if ((uid_t) -1 == tmpuid) { \
tmpuid = statp->st_uid; \
} \
\
if (((gid_t) -1 == old_gid) || (statp->st_gid == old_gid)) { \
tmpgid = new_gid; \
} \
if ((gid_t) -1 == tmpgid) { \
tmpgid = statp->st_gid; \
} \
\
return chown_function (dst, tmpuid, tmpgid); \
}
def_chown_if_needed (chown, const char *)
def_chown_if_needed (lchown, const char *)
def_chown_if_needed (fchown, int)
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