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/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
#include "libbb.h"
#include "bb_archive.h"
void FAST_FUNC data_extract_all(archive_handle_t *archive_handle)
{
file_header_t *file_header = archive_handle->file_header;
int dst_fd;
int res;
char *hard_link;
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
char *dst_name;
#else
# define dst_name (file_header->name)
#endif
#if ENABLE_FEATURE_TAR_SELINUX
char *sctx = archive_handle->tar__sctx[PAX_NEXT_FILE];
if (!sctx)
sctx = archive_handle->tar__sctx[PAX_GLOBAL];
if (sctx) { /* setfscreatecon is 4 syscalls, avoid if possible */
setfscreatecon(sctx);
free(archive_handle->tar__sctx[PAX_NEXT_FILE]);
archive_handle->tar__sctx[PAX_NEXT_FILE] = NULL;
}
#endif
/* Hard links are encoded as regular files of size 0
* with a nonempty link field */
hard_link = NULL;
if (S_ISREG(file_header->mode) && file_header->size == 0)
hard_link = file_header->link_target;
#if ENABLE_FEATURE_TAR_LONG_OPTIONS
dst_name = file_header->name;
if (archive_handle->tar__strip_components) {
unsigned n = archive_handle->tar__strip_components;
do {
dst_name = strchr(dst_name, '/');
if (!dst_name || dst_name[1] == '\0') {
data_skip(archive_handle);
goto ret;
}
dst_name++;
/*
* Link target is shortened only for hardlinks:
* softlinks restored unchanged.
*/
if (hard_link) {
// GNU tar 1.26 does not check that we reached end of link name:
// if "dir/hardlink" is hardlinked to "file",
// tar xvf a.tar --strip-components=1 says:
// tar: hardlink: Cannot hard link to '': No such file or directory
// and continues processing. We silently skip such entries.
hard_link = strchr(hard_link, '/');
if (!hard_link || hard_link[1] == '\0') {
data_skip(archive_handle);
goto ret;
}
hard_link++;
}
} while (--n != 0);
}
#endif
if (archive_handle->ah_flags & ARCHIVE_CREATE_LEADING_DIRS) {
char *slash = strrchr(dst_name, '/');
if (slash) {
*slash = '\0';
bb_make_directory(dst_name, -1, FILEUTILS_RECUR);
*slash = '/';
}
}
if (archive_handle->ah_flags & ARCHIVE_UNLINK_OLD) {
/* Remove the entry if it exists */
if (!S_ISDIR(file_header->mode)) {
if (hard_link) {
/* Ugly special case:
* tar cf t.tar hardlink1 hardlink2 hardlink1
* results in this tarball structure:
* hardlink1
* hardlink2 -> hardlink1
* hardlink1 -> hardlink1 <== !!!
*/
if (strcmp(hard_link, dst_name) == 0)
goto ret;
}
/* Proceed with deleting */
if (unlink(dst_name) == -1
&& errno != ENOENT
) {
bb_perror_msg_and_die("can't remove old file %s",
dst_name);
}
}
}
else if (archive_handle->ah_flags & ARCHIVE_EXTRACT_NEWER) {
/* Remove the existing entry if its older than the extracted entry */
struct stat existing_sb;
if (lstat(dst_name, &existing_sb) == -1) {
if (errno != ENOENT) {
bb_perror_msg_and_die("can't stat old file");
}
}
else if (existing_sb.st_mtime >= file_header->mtime) {
if (!(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
&& !S_ISDIR(file_header->mode)
) {
bb_error_msg("%s not created: newer or "
"same age file exists", dst_name);
}
data_skip(archive_handle);
goto ret;
}
else if ((unlink(dst_name) == -1) && (errno != EISDIR)) {
bb_perror_msg_and_die("can't remove old file %s",
dst_name);
}
}
/* Handle hard links separately */
if (hard_link) {
res = link(hard_link, dst_name);
if (res != 0 && !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)) {
/* shared message */
bb_perror_msg("can't create %slink '%s' to '%s'",
"hard",
dst_name,
hard_link
);
}
/* Hardlinks have no separate mode/ownership, skip chown/chmod */
goto ret;
}
/* Create the filesystem entry */
switch (file_header->mode & S_IFMT) {
case S_IFREG: {
/* Regular file */
char *dst_nameN;
int flags = O_WRONLY | O_CREAT | O_EXCL;
if (archive_handle->ah_flags & ARCHIVE_O_TRUNC)
flags = O_WRONLY | O_CREAT | O_TRUNC;
dst_nameN = dst_name;
#ifdef ARCHIVE_REPLACE_VIA_RENAME
if (archive_handle->ah_flags & ARCHIVE_REPLACE_VIA_RENAME)
/* rpm-style temp file name */
dst_nameN = xasprintf("%s;%x", dst_name, (int)getpid());
#endif
dst_fd = xopen3(dst_nameN,
flags,
file_header->mode
);
bb_copyfd_exact_size(archive_handle->src_fd, dst_fd, file_header->size);
close(dst_fd);
#ifdef ARCHIVE_REPLACE_VIA_RENAME
if (archive_handle->ah_flags & ARCHIVE_REPLACE_VIA_RENAME) {
xrename(dst_nameN, dst_name);
free(dst_nameN);
}
#endif
break;
}
case S_IFDIR:
res = mkdir(dst_name, file_header->mode);
if ((res == -1)
&& (errno != EISDIR) /* btw, Linux doesn't return this */
&& (errno != EEXIST)
&& !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
) {
bb_perror_msg("can't make dir %s", dst_name);
}
break;
case S_IFLNK:
/* Symlink */
//TODO: what if file_header->link_target == NULL (say, corrupted tarball?)
/* To avoid a directory traversal attack via symlinks,
* for certain link targets postpone creation of symlinks.
*
* For example, consider a .tar created via:
* $ tar cvf bug.tar anything.txt
* $ ln -s /tmp symlink
* $ tar --append -f bug.tar symlink
* $ rm symlink
* $ mkdir symlink
* $ tar --append -f bug.tar symlink/evil.py
*
* This will result in an archive that contains:
* $ tar --list -f bug.tar
* anything.txt
* symlink [-> /tmp]
* symlink/evil.py
*
* Untarring bug.tar would otherwise place evil.py in '/tmp'.
*/
if (file_header->link_target[0] == '/'
|| strstr(file_header->link_target, "..")
) {
llist_add_to(&archive_handle->symlink_placeholders,
xasprintf("%s%c%s", file_header->name, '\0', file_header->link_target)
);
break;
}
res = symlink(file_header->link_target, dst_name);
if (res != 0
&& !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
) {
/* shared message */
bb_perror_msg("can't create %slink '%s' to '%s'",
"sym",
dst_name,
file_header->link_target
);
}
break;
case S_IFSOCK:
case S_IFBLK:
case S_IFCHR:
case S_IFIFO:
res = mknod(dst_name, file_header->mode, file_header->device);
if ((res == -1)
&& !(archive_handle->ah_flags & ARCHIVE_EXTRACT_QUIET)
) {
bb_perror_msg("can't create node %s", dst_name);
}
break;
default:
bb_error_msg_and_die("unrecognized file type");
}
if (!S_ISLNK(file_header->mode)) {
if (!(archive_handle->ah_flags & ARCHIVE_DONT_RESTORE_OWNER)) {
uid_t uid = file_header->uid;
gid_t gid = file_header->gid;
#if ENABLE_FEATURE_TAR_UNAME_GNAME
if (!(archive_handle->ah_flags & ARCHIVE_NUMERIC_OWNER)) {
if (file_header->tar__uname) {
//TODO: cache last name/id pair?
struct passwd *pwd = getpwnam(file_header->tar__uname);
if (pwd) uid = pwd->pw_uid;
}
if (file_header->tar__gname) {
struct group *grp = getgrnam(file_header->tar__gname);
if (grp) gid = grp->gr_gid;
}
}
#endif
/* GNU tar 1.15.1 uses chown, not lchown */
chown(dst_name, uid, gid);
}
/* uclibc has no lchmod, glibc is even stranger -
* it has lchmod which seems to do nothing!
* so we use chmod... */
if (!(archive_handle->ah_flags & ARCHIVE_DONT_RESTORE_PERM)) {
chmod(dst_name, file_header->mode);
}
if (archive_handle->ah_flags & ARCHIVE_RESTORE_DATE) {
struct timeval t[2];
t[1].tv_sec = t[0].tv_sec = file_header->mtime;
t[1].tv_usec = t[0].tv_usec = 0;
utimes(dst_name, t);
}
}
ret: ;
#if ENABLE_FEATURE_TAR_SELINUX
if (sctx) {
/* reset the context after creating an entry */
setfscreatecon(NULL);
}
#endif
}
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