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/* vi: set sw=4 ts=4: */
/* 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 "libbb.h"
#include "unarchive.h"
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
static char *longname;
static char *linkname;
#else
enum {
longname = 0,
linkname = 0,
};
#endif
/* NB: _DESTROYS_ str[len] character! */
static unsigned long long getOctal(char *str, int len)
{
unsigned long long v;
/* Actually, tar header allows leading spaces also.
* Oh well, we will be liberal and skip this...
* The only downside probably is that we allow "-123" too :)
if (*str < '0' || *str > '7')
bb_error_msg_and_die("corrupted octal value in tar header");
*/
str[len] = '\0';
v = strtoull(str, &str, 8);
if (*str)
bb_error_msg_and_die("corrupted octal value in tar header");
return v;
}
#define GET_OCTAL(a) getOctal((a), sizeof(a))
void BUG_tar_header_size(void);
char get_header_tar(archive_handle_t *archive_handle)
{
static int end;
file_header_t *file_header = archive_handle->file_header;
struct {
/* ustar header, Posix 1003.1 */
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 */
} tar;
char *cp;
int sum, i;
int parse_names;
if (sizeof(tar) != 512)
BUG_tar_header_size();
again:
/* Align header */
data_align(archive_handle, 512);
again_after_align:
xread(archive_handle->src_fd, &tar, 512);
archive_handle->offset += 512;
/* If there is no filename its an empty header */
if (tar.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 (full_read(archive_handle->src_fd, &tar, 512) == 512)
/* repeat */;
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.magic, "ustar", 5) != 0) {
#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
if (memcmp(tar.magic, "\0\0\0\0", 5) != 0)
#endif
bb_error_msg_and_die("invalid tar magic");
}
/* Do checksum on headers */
sum = ' ' * sizeof(tar.chksum);
for (i = 0; i < 148 ; i++) {
sum += ((char*)&tar)[i];
}
for (i = 156; i < 512 ; i++) {
sum += ((char*)&tar)[i];
}
/* This field does not need special treatment (getOctal) */
if (sum != xstrtoul(tar.chksum, 8)) {
bb_error_msg_and_die("invalid tar header checksum");
}
/* 0 is reserved for high perf file, treat as normal file */
if (!tar.typeflag) tar.typeflag = '0';
parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7');
/* getOctal trashes subsequent field, therefore we call it
* on fields in reverse order */
if (tar.devmajor[0]) {
unsigned minor = GET_OCTAL(tar.devminor);
unsigned major = GET_OCTAL(tar.devmajor);
file_header->device = makedev(major, minor);
}
file_header->link_name = NULL;
if (!linkname && parse_names && tar.linkname[0]) {
/* we trash magic[0] here, it's ok */
tar.linkname[sizeof(tar.linkname)] = '\0';
file_header->link_name = xstrdup(tar.linkname);
/* FIXME: what if we have non-link object with link_name? */
/* Will link_name be free()ed? */
}
file_header->mtime = GET_OCTAL(tar.mtime);
file_header->size = GET_OCTAL(tar.size);
file_header->gid = GET_OCTAL(tar.gid);
file_header->uid = GET_OCTAL(tar.uid);
/* Set bits 0-11 of the files mode */
file_header->mode = 07777 & GET_OCTAL(tar.mode);
file_header->name = NULL;
if (!longname && parse_names) {
/* we trash mode[0] here, it's ok */
tar.name[sizeof(tar.name)] = '\0';
if (tar.prefix[0]) {
/* and padding[0] */
tar.prefix[sizeof(tar.prefix)] = '\0';
file_header->name = concat_path_file(tar.prefix, tar.name);
} else
file_header->name = xstrdup(tar.name);
}
/* Set bits 12-15 of the files mode */
/* (typeflag was not trashed because chksum does not use getOctal) */
switch (tar.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 '7':
/* case 0: */
case '0':
#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
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;
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
case 'L':
/* free: paranoia: tar with several consecutive longnames */
free(longname);
/* For paranoia reasons we allocate extra NUL char */
longname = xzalloc(file_header->size + 1);
/* We read ASCIZ string, including NUL */
xread(archive_handle->src_fd, longname, file_header->size);
archive_handle->offset += file_header->size;
/* return get_header_tar(archive_handle); */
/* gcc 4.1.1 didn't optimize it into jump */
/* so we will do it ourself, this also saves stack */
goto again;
case 'K':
free(linkname);
linkname = xzalloc(file_header->size + 1);
xread(archive_handle->src_fd, linkname, file_header->size);
archive_handle->offset += file_header->size;
/* return get_header_tar(archive_handle); */
goto again;
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 */
#endif
case 'g': /* pax global header */
case 'x': { /* pax extended header */
off_t sz;
bb_error_msg("warning: skipping header '%c'", tar.typeflag);
sz = (file_header->size + 511) & ~(off_t)511;
archive_handle->offset += sz;
sz >>= 9; /* sz /= 512 but w/o contortions for signed div */
while (sz--)
xread(archive_handle->src_fd, &tar, 512);
/* return get_header_tar(archive_handle); */
goto again_after_align;
}
default:
bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag);
}
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
if (longname) {
file_header->name = longname;
longname = NULL;
}
if (linkname) {
file_header->link_name = linkname;
linkname = NULL;
}
#endif
if (!strncmp(file_header->name, "/../"+1, 3)
|| strstr(file_header->name, "/../")
) {
bb_error_msg_and_die("name with '..' encountered: '%s'",
file_header->name);
}
/* Strip trailing '/' in directories */
/* Must be done after mode is set as '/' is used to check if it's a directory */
cp = last_char_is(file_header->name, '/');
if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
archive_handle->action_header(archive_handle->file_header);
/* Note that we kill the '/' only after action_header() */
/* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */
if (cp) *cp = '\0';
archive_handle->flags |= ARCHIVE_EXTRACT_QUIET;
archive_handle->action_data(archive_handle);
llist_add_to(&(archive_handle->passed), file_header->name);
} else {
data_skip(archive_handle);
free(file_header->name);
}
archive_handle->offset += file_header->size;
free(file_header->link_name);
/* Do not free(file_header->name)! */
return EXIT_SUCCESS;
}
|
