shadow/libmisc/copydir.c

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/*
* Copyright (c) 1991 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 2001, Marek Michałkiewicz
* Copyright (c) 2003 - 2006, Tomasz Kłoczko
* Copyright (c) 2007 - 2008, Nicolas François
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#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
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,
long int uid, long int gid);
static int copy_dir (const char *src, const char *dst,
const struct stat *statp, const struct timeval mt[],
long int uid, long int gid);
#ifdef S_IFLNK
static char *readlink_malloc (const char *filename);
static int copy_symlink (const char *src, const char *dst,
const struct stat *statp, const struct timeval mt[],
long int uid, long int gid);
#endif
static int copy_hardlink (const char *src, const char *dst,
struct link_name *lp);
static int copy_special (const char *dst,
const struct stat *statp, const struct timeval mt[],
long int uid, long int gid);
static int copy_file (const char *src, const char *dst,
const struct stat *statp, const struct timeval mt[],
long int uid, long int gid);
#ifdef WITH_SELINUX
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/*
* selinux_file_context - Set the security context before any file or
* directory creation.
*
* selinux_file_context () should be called before any creation of file,
* symlink, directory, ...
*
* Callers may have to Reset SELinux to create files with default
* contexts:
* setfscreatecon (NULL);
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*/
int selinux_file_context (const char *dst_name)
{
static bool selinux_checked = false;
static bool selinux_enabled;
security_context_t scontext = NULL;
if (!selinux_checked) {
selinux_enabled = is_selinux_enabled () > 0;
selinux_checked = true;
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}
if (selinux_enabled) {
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/* Get the default security context for this file */
if (matchpathcon (dst_name, 0, &scontext) < 0) {
if (security_getenforce () != 0) {
return 1;
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}
}
/* Set the security context for the next created file */
if (setfscreatecon (scontext) < 0) {
if (security_getenforce () != 0) {
return 1;
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}
}
freecon (scontext);
}
return 0;
}
#endif
/*
* 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) {
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if (lp->ln_next == ln) {
break;
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}
}
if (NULL == lp) {
free (ln->ln_name);
free (ln);
return;
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}
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;
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}
}
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if (sb->st_nlink == 1) {
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return NULL;
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}
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);
snprintf (lp->ln_name, len, "%s%s", dst_orig, name + src_len);
lp->ln_next = links;
links = lp;
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return NULL;
}
/*
* copy_tree - copy files in a directory tree
*
* copy_tree() walks a directory tree and copies ordinary files
* as it goes.
*/
int copy_tree (const char *src_root, const char *dst_root,
long int uid, long int gid)
{
int err = 0;
bool set_orig = false;
struct DIRECT *ent;
DIR *dir;
/*
* 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;
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}
/*
* 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.
*/
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dir = opendir (src_root);
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if (NULL == dir) {
return -1;
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}
if (src_orig == NULL) {
src_orig = src_root;
dst_orig = dst_root;
set_orig = true;
}
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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.
*/
snprintf (src_name, src_len, "%s/%s",
src_root, ent->d_name);
snprintf (dst_name, dst_len, "%s/%s",
dst_root, ent->d_name);
err = copy_entry (src_name, dst_name, uid, 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;
}
#ifdef WITH_SELINUX
/* Reset SELinux to create files with default contexts */
setfscreatecon (NULL);
#endif
/* FIXME: with the call to remove_link, we could also check that
* no links remain in links.
* assert (NULL == links); */
return err;
}
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/*
* 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 uid/gid.
*
* If uid (resp. gid) is equal to -1, the user (resp. group) will
* not be modified.
*/
static int copy_entry (const char *src, const char *dst,
long int uid, long int 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
mt[0].tv_sec = sb.st_atime;
#ifdef HAVE_STRUCT_STAT_ST_ATIMENSEC
mt[0].tv_usec = sb.st_atimensec / 1000;
#else
mt[0].tv_usec = 0;
#endif
#endif
#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
mt[1].tv_sec = sb.st_mtime;
#ifdef HAVE_STRUCT_STAT_ST_MTIMENSEC
mt[1].tv_usec = sb.st_mtimensec / 1000;
#else
mt[1].tv_usec = 0;
#endif
#endif
if (S_ISDIR (sb.st_mode)) {
err = copy_dir (src, dst, &sb, mt, uid, gid);
}
#ifdef S_IFLNK
/*
* Copy any symbolic links
*/
else if (S_ISLNK (sb.st_mode)) {
err = copy_symlink (src, dst, &sb, mt, uid, gid);
}
#endif
/*
* See if this is a previously copied link
*/
else if ((lp = check_link (src, &sb)) != NULL) {
err = copy_hardlink (src, dst, 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 (dst, &sb, mt, uid, 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, &sb, mt, uid, gid);
}
}
return err;
}
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/*
* copy_dir - copy a directory
*
* Copy a directory (recursively) from src to dst.
*
* statp, mt, uid, 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,
const struct stat *statp, const struct timeval mt[],
long int uid, long int gid)
{
int err = 0;
/*
* Create a new target directory, make it owned by
* the user and then recursively copy that directory.
*/
#ifdef WITH_SELINUX
selinux_file_context (dst);
#endif
if ( (mkdir (dst, statp->st_mode) != 0)
|| (chown (dst,
(uid == - 1) ? statp->st_uid : (uid_t) uid,
(gid == - 1) ? statp->st_gid : (gid_t) gid) != 0)
|| (chmod (dst, statp->st_mode) != 0)
|| (copy_tree (src, dst, uid, 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 char *readlink_malloc (const char *filename)
{
size_t size = 1024;
while (1) {
ssize_t nchars;
char *buffer = (char *) malloc (size);
if (NULL == buffer) {
return NULL;
}
nchars = readlink (filename, buffer, size);
if (nchars < 0) {
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;
}
}
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/*
* copy_symlink - copy a symlink
*
* Copy a symlink from src to dst.
*
* statp, mt, uid, 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,
const struct stat *statp, const struct timeval mt[],
long int uid, long int 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 *) malloc (len);
snprintf (dummy, len, "%s%s",
dst_orig,
oldlink + strlen (src_orig));
free (oldlink);
oldlink = dummy;
}
#ifdef WITH_SELINUX
selinux_file_context (dst);
#endif
if ( (symlink (oldlink, dst) != 0)
|| (lchown (dst,
(uid == -1) ? statp->st_uid : (uid_t) uid,
(gid == -1) ? statp->st_gid : (gid_t) gid) != 0)) {
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
*/
lutimes (dst, mt);
#endif
return 0;
}
#endif
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/*
* 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 *src, const char *dst,
struct link_name *lp)
{
/* TODO: selinux needed? */
if (link (lp->ln_name, dst) != 0) {
return -1;
}
/* FIXME: why is it unlinked? This is a copy, not a move*/
if (unlink (src) != 0) {
return -1;
}
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/* FIXME: idem, although it may never be used again */
/* If the file could be unlinked, decrement the links counter,
* and delete the file if it was the last reference */
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lp->ln_count--;
if (lp->ln_count <= 0) {
remove_link (lp);
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}
return 0;
}
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/*
* copy_special - copy a special file
*
* Copy a special file from src to dst.
*
* statp, mt, uid, 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 *dst,
const struct stat *statp, const struct timeval mt[],
long int uid, long int gid)
{
int err = 0;
#ifdef WITH_SELINUX
selinux_file_context (dst);
#endif
if ( (mknod (dst, statp->st_mode & ~07777, statp->st_rdev) != 0)
|| (chown (dst,
(uid == -1) ? statp->st_uid : (uid_t) uid,
(gid == -1) ? statp->st_gid : (gid_t) gid) != 0)
|| (chmod (dst, statp->st_mode & 07777) != 0)
|| (utimes (dst, mt) != 0)) {
err = -1;
}
return err;
}
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/*
* copy_file - copy a file
*
* Copy a file from src to dst.
*
* statp, mt, uid, 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,
const struct stat *statp, const struct timeval mt[],
long int uid, long int gid)
{
int err = 0;
int ifd;
int ofd;
char buf[1024];
ssize_t cnt;
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ifd = open (src, O_RDONLY);
if (ifd < 0) {
return -1;
}
#ifdef WITH_SELINUX
selinux_file_context (dst);
#endif
ofd = open (dst, O_WRONLY | O_CREAT | O_TRUNC, statp->st_mode & 07777);
if ( (ofd < 0)
|| (fchown (ofd,
(uid == -1) ? statp->st_uid : (uid_t) uid,
(gid == -1) ? statp->st_gid : (gid_t) gid) != 0)
|| (fchmod (ofd, statp->st_mode & 07777) != 0)) {
(void) close (ifd);
return -1;
}
while ((cnt = read (ifd, buf, sizeof buf)) > 0) {
if (write (ofd, buf, (size_t)cnt) != cnt) {
return -1;
}
}
(void) close (ifd);
#ifdef HAVE_FUTIMES
if (futimes (ofd, mt) != 0) {
return -1;
}
#endif
if (close (ofd) != 0) {
return -1;
}
#ifndef HAVE_FUTIMES
if (utimes(dst, mt) != 0) {
return -1;
}
#endif
return err;
}
/*
* remove_tree - delete a directory tree
*
* remove_tree() walks a directory tree and deletes all the files
* and directories.
* At the end, it deletes the root directory itself.
*/
int remove_tree (const char *root)
{
char *new_name = NULL;
int err = 0;
struct DIRECT *ent;
struct stat sb;
DIR *dir;
/*
* Make certain the directory exists.
*/
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if (access (root, F_OK) != 0) {
return -1;
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}
/*
* 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.
*/
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dir = opendir (root);
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if (NULL == dir) {
return -1;
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}
while ((ent = readdir (dir))) {
size_t new_len = strlen (root) + strlen (ent->d_name) + 2;
/*
* Skip the "." and ".." entries
*/
if (strcmp (ent->d_name, ".") == 0 ||
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strcmp (ent->d_name, "..") == 0) {
continue;
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}
/*
* Make the filename for the current entry.
*/
if (NULL != new_name) {
free (new_name);
}
new_name = (char *) malloc (new_len);
if (NULL == new_name) {
err = -1;
break;
}
snprintf (new_name, new_len, "%s/%s", root, ent->d_name);
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if (LSTAT (new_name, &sb) == -1) {
continue;
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}
if (S_ISDIR (sb.st_mode)) {
/*
* Recursively delete this directory.
*/
if (remove_tree (new_name) != 0) {
err = -1;
break;
}
} else {
/*
* Delete the file.
*/
if (unlink (new_name) != 0) {
err = -1;
break;
}
}
}
if (NULL != new_name) {
free (new_name);
}
(void) closedir (dir);
if (0 == err) {
if (rmdir (root) != 0) {
err = -1;
}
}
return err;
}
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