busybox/archival/libunarchive/get_header_tar.c
Rob Landley 06249fee39 Bug 640: a filename of length exactly 100 could bleed into the next field on
display or extract.  (Only shows up when no gnu longname extension, either
because it's disabled or because tarball hasn't got it.)
2006-02-20 19:28:53 +00:00

219 lines
6.0 KiB
C

/* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*
* FIXME:
* In privileged mode if uname and gname map to a uid and gid then use the
* mapped value instead of the uid/gid values in tar header
*
* References:
* GNU tar and star man pages,
* Opengroup's ustar interchange format,
* http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/sysmacros.h> /* For makedev */
#include "unarchive.h"
#include "libbb.h"
#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
static char *longname = NULL;
static char *linkname = NULL;
#endif
extern char get_header_tar(archive_handle_t *archive_handle)
{
file_header_t *file_header = archive_handle->file_header;
union {
/* ustar header, Posix 1003.1 */
unsigned char raw[512];
struct {
char name[100]; /* 0-99 */
char mode[8]; /* 100-107 */
char uid[8]; /* 108-115 */
char gid[8]; /* 116-123 */
char size[12]; /* 124-135 */
char mtime[12]; /* 136-147 */
char chksum[8]; /* 148-155 */
char typeflag; /* 156-156 */
char linkname[100]; /* 157-256 */
char magic[6]; /* 257-262 */
char version[2]; /* 263-264 */
char uname[32]; /* 265-296 */
char gname[32]; /* 297-328 */
char devmajor[8]; /* 329-336 */
char devminor[8]; /* 337-344 */
char prefix[155]; /* 345-499 */
char padding[12]; /* 500-512 */
} formated;
} tar;
long sum = 0;
long i;
static int end = 0;
/* Align header */
data_align(archive_handle, 512);
if (bb_full_read(archive_handle->src_fd, tar.raw, 512) != 512) {
/* Assume end of file */
bb_error_msg_and_die("Short header");
//return(EXIT_FAILURE);
}
archive_handle->offset += 512;
/* If there is no filename its an empty header */
if (tar.formated.name[0] == 0) {
if (end) {
/* This is the second consecutive empty header! End of archive!
* Read until the end to empty the pipe from gz or bz2
*/
while (bb_full_read(archive_handle->src_fd, tar.raw, 512) == 512);
return(EXIT_FAILURE);
}
end = 1;
return(EXIT_SUCCESS);
}
end = 0;
/* Check header has valid magic, "ustar" is for the proper tar
* 0's are for the old tar format
*/
if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
#ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
if (strncmp(tar.formated.magic, "\0\0\0\0\0", 5) != 0)
#endif
bb_error_msg_and_die("Invalid tar magic");
}
/* Do checksum on headers */
for (i = 0; i < 148 ; i++) {
sum += tar.raw[i];
}
sum += ' ' * 8;
for (i = 156; i < 512 ; i++) {
sum += tar.raw[i];
}
if (sum != strtol(tar.formated.chksum, NULL, 8)) {
bb_error_msg("Invalid tar header checksum");
return(EXIT_FAILURE);
}
#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
if (longname) {
file_header->name = longname;
longname = NULL;
}
else if (linkname) {
file_header->name = linkname;
linkname = NULL;
} else
#endif
{
file_header->name = strndup(tar.formated.name,100);
if (tar.formated.prefix[0]) {
char *temp = file_header->name;
file_header->name = concat_path_file(tar.formated.prefix, temp);
free(temp);
}
}
file_header->uid = strtol(tar.formated.uid, NULL, 8);
file_header->gid = strtol(tar.formated.gid, NULL, 8);
file_header->size = strtol(tar.formated.size, NULL, 8);
file_header->mtime = strtol(tar.formated.mtime, NULL, 8);
file_header->link_name = (tar.formated.linkname[0] != '\0') ?
bb_xstrdup(tar.formated.linkname) : NULL;
file_header->device = makedev(strtol(tar.formated.devmajor, NULL, 8),
strtol(tar.formated.devminor, NULL, 8));
/* Set bits 0-11 of the files mode */
file_header->mode = 07777 & strtol(tar.formated.mode, NULL, 8);
/* Set bits 12-15 of the files mode */
switch (tar.formated.typeflag) {
/* busybox identifies hard links as being regular files with 0 size and a link name */
case '1':
file_header->mode |= S_IFREG;
break;
case 'x':
case 'g':
bb_error_msg_and_die("pax is not tar");
break;
case '7':
/* Reserved for high performance files, treat as normal file */
case 0:
case '0':
#ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
if (last_char_is(file_header->name, '/')) {
file_header->mode |= S_IFDIR;
} else
#endif
file_header->mode |= S_IFREG;
break;
case '2':
file_header->mode |= S_IFLNK;
break;
case '3':
file_header->mode |= S_IFCHR;
break;
case '4':
file_header->mode |= S_IFBLK;
break;
case '5':
file_header->mode |= S_IFDIR;
break;
case '6':
file_header->mode |= S_IFIFO;
break;
#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
case 'L': {
longname = xmalloc(file_header->size + 1);
archive_xread_all(archive_handle, longname, file_header->size);
longname[file_header->size] = '\0';
archive_handle->offset += file_header->size;
return(get_header_tar(archive_handle));
}
case 'K': {
linkname = xmalloc(file_header->size + 1);
archive_xread_all(archive_handle, linkname, file_header->size);
linkname[file_header->size] = '\0';
archive_handle->offset += file_header->size;
file_header->name = linkname;
return(get_header_tar(archive_handle));
}
case 'D': /* GNU dump dir */
case 'M': /* Continuation of multi volume archive*/
case 'N': /* Old GNU for names > 100 characters */
case 'S': /* Sparse file */
case 'V': /* Volume header */
bb_error_msg("Ignoring GNU extension type %c", tar.formated.typeflag);
#endif
default:
bb_error_msg("Unknown typeflag: 0x%x", tar.formated.typeflag);
}
{ /* Strip trailing '/' in directories */
/* Must be done after mode is set as '/' is used to check if its a directory */
char *tmp = last_char_is(file_header->name, '/');
if (tmp) {
*tmp = '\0';
}
}
if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
archive_handle->action_header(archive_handle->file_header);
archive_handle->flags |= ARCHIVE_EXTRACT_QUIET;
archive_handle->action_data(archive_handle);
archive_handle->passed = llist_add_to(archive_handle->passed, file_header->name);
} else {
data_skip(archive_handle);
}
archive_handle->offset += file_header->size;
free(file_header->link_name);
return(EXIT_SUCCESS);
}