369 lines
11 KiB
C
369 lines
11 KiB
C
/* vi: set sw=4 ts=4: */
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/* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*
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* FIXME:
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* In privileged mode if uname and gname map to a uid and gid then use the
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* mapped value instead of the uid/gid values in tar header
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*
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* References:
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* GNU tar and star man pages,
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* Opengroup's ustar interchange format,
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* http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
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*/
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#include "libbb.h"
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#include "unarchive.h"
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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static char *longname;
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static char *linkname;
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#else
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enum {
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longname = 0,
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linkname = 0,
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};
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#endif
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/* NB: _DESTROYS_ str[len] character! */
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static unsigned long long getOctal(char *str, int len)
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{
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unsigned long long v;
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/* Actually, tar header allows leading spaces also.
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* Oh well, we will be liberal and skip this...
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* The only downside probably is that we allow "-123" too :)
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if (*str < '0' || *str > '7')
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bb_error_msg_and_die("corrupted octal value in tar header");
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*/
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str[len] = '\0';
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v = strtoull(str, &str, 8);
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if (*str && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY || *str != ' '))
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bb_error_msg_and_die("corrupted octal value in tar header");
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return v;
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}
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#define GET_OCTAL(a) getOctal((a), sizeof(a))
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void BUG_tar_header_size(void);
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char get_header_tar(archive_handle_t *archive_handle)
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{
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static smallint end;
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#if ENABLE_FEATURE_TAR_AUTODETECT
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static smallint not_first;
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#endif
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file_header_t *file_header = archive_handle->file_header;
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struct {
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/* ustar header, Posix 1003.1 */
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char name[100]; /* 0-99 */
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char mode[8]; /* 100-107 */
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char uid[8]; /* 108-115 */
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char gid[8]; /* 116-123 */
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char size[12]; /* 124-135 */
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char mtime[12]; /* 136-147 */
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char chksum[8]; /* 148-155 */
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char typeflag; /* 156-156 */
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char linkname[100]; /* 157-256 */
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/* POSIX: "ustar" NUL "00" */
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/* GNU tar: "ustar " NUL */
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/* Normally it's defined as magic[6] followed by
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* version[2], but we put them together to save code.
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*/
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char magic[8]; /* 257-264 */
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char uname[32]; /* 265-296 */
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char gname[32]; /* 297-328 */
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char devmajor[8]; /* 329-336 */
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char devminor[8]; /* 337-344 */
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char prefix[155]; /* 345-499 */
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char padding[12]; /* 500-512 */
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} tar;
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char *cp;
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int i, sum_u, sum;
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#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
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int sum_s;
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#endif
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int parse_names;
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if (sizeof(tar) != 512)
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BUG_tar_header_size();
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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again:
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#endif
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/* Align header */
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data_align(archive_handle, 512);
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again_after_align:
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#if ENABLE_DESKTOP
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i = full_read(archive_handle->src_fd, &tar, 512);
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/* if GNU tar sees EOF in above read, it says:
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* "tar: A lone zero block at N", where N = kilobyte
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* where EOF was met (not EOF block, actual EOF!),
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* and tar will exit with error code 0.
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* We will mimic exit(0), although we will not mimic
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* the message and we don't check whether we indeed
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* saw zero block directly before this. */
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if (i == 0)
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xfunc_error_retval = 0;
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if (i != 512)
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bb_error_msg_and_die("short read");
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#else
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xread(archive_handle->src_fd, &tar, 512);
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#endif
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archive_handle->offset += 512;
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/* If there is no filename its an empty header */
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if (tar.name[0] == 0 && tar.prefix[0] == 0) {
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if (end) {
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/* This is the second consecutive empty header! End of archive!
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* Read until the end to empty the pipe from gz or bz2
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*/
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while (full_read(archive_handle->src_fd, &tar, 512) == 512)
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continue;
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return EXIT_FAILURE;
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}
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end = 1;
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return EXIT_SUCCESS;
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}
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end = 0;
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/* Check header has valid magic, "ustar" is for the proper tar,
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* five NULs are for the old tar format */
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if (strncmp(tar.magic, "ustar", 5) != 0
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&& (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
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|| memcmp(tar.magic, "\0\0\0\0", 5) != 0)
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) {
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#if ENABLE_FEATURE_TAR_AUTODETECT
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char (*get_header_ptr)(archive_handle_t *);
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/* tar gz/bz autodetect: check for gz/bz2 magic.
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* If it is the very first block, and we see the magic,
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* we can switch to get_header_tar_gz/bz2/lzma().
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* Needs seekable fd. I wish recv(MSG_PEEK) would work
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* on any fd... */
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if (not_first)
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goto err;
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#if ENABLE_FEATURE_TAR_GZIP
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if (tar.name[0] == 0x1f && tar.name[1] == 0x8b) { /* gzip */
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get_header_ptr = get_header_tar_gz;
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} else
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#endif
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#if ENABLE_FEATURE_TAR_BZIP2
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if (tar.name[0] == 'B' && tar.name[1] == 'Z'
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&& tar.name[2] == 'h' && isdigit(tar.name[3])
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) { /* bzip2 */
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get_header_ptr = get_header_tar_bz2;
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} else
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#endif
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goto err;
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if (lseek(archive_handle->src_fd, -512, SEEK_CUR) != 0)
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goto err;
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while (get_header_ptr(archive_handle) == EXIT_SUCCESS)
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continue;
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return EXIT_FAILURE;
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err:
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#endif /* FEATURE_TAR_AUTODETECT */
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bb_error_msg_and_die("invalid tar magic");
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}
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#if ENABLE_FEATURE_TAR_AUTODETECT
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not_first = 1;
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#endif
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/* Do checksum on headers.
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* POSIX says that checksum is done on unsigned bytes, but
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* Sun and HP-UX gets it wrong... more details in
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* GNU tar source. */
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#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
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sum_s = ' ' * sizeof(tar.chksum);
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#endif
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sum_u = ' ' * sizeof(tar.chksum);
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for (i = 0; i < 148; i++) {
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sum_u += ((unsigned char*)&tar)[i];
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#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
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sum_s += ((signed char*)&tar)[i];
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#endif
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}
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for (i = 156; i < 512; i++) {
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sum_u += ((unsigned char*)&tar)[i];
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#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
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sum_s += ((signed char*)&tar)[i];
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#endif
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}
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#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
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sum = strtoul(tar.chksum, &cp, 8);
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if ((*cp && *cp != ' ')
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|| (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum))
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) {
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bb_error_msg_and_die("invalid tar header checksum");
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}
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#else
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/* This field does not need special treatment (getOctal) */
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sum = xstrtoul(tar.chksum, 8);
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if (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) {
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bb_error_msg_and_die("invalid tar header checksum");
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}
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#endif
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/* 0 is reserved for high perf file, treat as normal file */
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if (!tar.typeflag) tar.typeflag = '0';
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parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7');
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/* getOctal trashes subsequent field, therefore we call it
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* on fields in reverse order */
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if (tar.devmajor[0]) {
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char t = tar.prefix[0];
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/* we trash prefix[0] here, but we DO need it later! */
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unsigned minor = GET_OCTAL(tar.devminor);
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unsigned major = GET_OCTAL(tar.devmajor);
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file_header->device = makedev(major, minor);
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tar.prefix[0] = t;
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}
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file_header->link_target = NULL;
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if (!linkname && parse_names && tar.linkname[0]) {
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file_header->link_target = xstrndup(tar.linkname, sizeof(tar.linkname));
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/* FIXME: what if we have non-link object with link_target? */
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/* Will link_target be free()ed? */
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}
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#if ENABLE_FEATURE_TAR_UNAME_GNAME
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file_header->uname = tar.uname[0] ? xstrndup(tar.uname, sizeof(tar.uname)) : NULL;
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file_header->gname = tar.gname[0] ? xstrndup(tar.gname, sizeof(tar.gname)) : NULL;
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#endif
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file_header->mtime = GET_OCTAL(tar.mtime);
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file_header->size = GET_OCTAL(tar.size);
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file_header->gid = GET_OCTAL(tar.gid);
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file_header->uid = GET_OCTAL(tar.uid);
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/* Set bits 0-11 of the files mode */
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file_header->mode = 07777 & GET_OCTAL(tar.mode);
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file_header->name = NULL;
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if (!longname && parse_names) {
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/* we trash mode[0] here, it's ok */
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//tar.name[sizeof(tar.name)] = '\0'; - gcc 4.3.0 would complain
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tar.mode[0] = '\0';
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if (tar.prefix[0]) {
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/* and padding[0] */
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//tar.prefix[sizeof(tar.prefix)] = '\0'; - gcc 4.3.0 would complain
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tar.padding[0] = '\0';
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file_header->name = concat_path_file(tar.prefix, tar.name);
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} else
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file_header->name = xstrdup(tar.name);
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}
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/* Set bits 12-15 of the files mode */
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/* (typeflag was not trashed because chksum does not use getOctal) */
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switch (tar.typeflag) {
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/* busybox identifies hard links as being regular files with 0 size and a link name */
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case '1':
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file_header->mode |= S_IFREG;
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break;
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case '7':
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/* case 0: */
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case '0':
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#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
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if (last_char_is(file_header->name, '/')) {
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file_header->mode |= S_IFDIR;
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} else
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#endif
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file_header->mode |= S_IFREG;
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break;
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case '2':
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file_header->mode |= S_IFLNK;
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break;
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case '3':
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file_header->mode |= S_IFCHR;
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break;
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case '4':
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file_header->mode |= S_IFBLK;
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break;
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case '5':
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file_header->mode |= S_IFDIR;
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break;
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case '6':
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file_header->mode |= S_IFIFO;
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break;
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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case 'L':
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/* free: paranoia: tar with several consecutive longnames */
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free(longname);
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/* For paranoia reasons we allocate extra NUL char */
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longname = xzalloc(file_header->size + 1);
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/* We read ASCIZ string, including NUL */
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xread(archive_handle->src_fd, longname, file_header->size);
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archive_handle->offset += file_header->size;
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/* return get_header_tar(archive_handle); */
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/* gcc 4.1.1 didn't optimize it into jump */
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/* so we will do it ourself, this also saves stack */
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goto again;
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case 'K':
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free(linkname);
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linkname = xzalloc(file_header->size + 1);
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xread(archive_handle->src_fd, linkname, file_header->size);
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archive_handle->offset += file_header->size;
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/* return get_header_tar(archive_handle); */
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goto again;
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case 'D': /* GNU dump dir */
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case 'M': /* Continuation of multi volume archive */
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case 'N': /* Old GNU for names > 100 characters */
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case 'S': /* Sparse file */
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case 'V': /* Volume header */
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#endif
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case 'g': /* pax global header */
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case 'x': { /* pax extended header */
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off_t sz;
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bb_error_msg("warning: skipping header '%c'", tar.typeflag);
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sz = (file_header->size + 511) & ~(off_t)511;
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archive_handle->offset += sz;
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sz >>= 9; /* sz /= 512 but w/o contortions for signed div */
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while (sz--)
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xread(archive_handle->src_fd, &tar, 512);
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/* return get_header_tar(archive_handle); */
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goto again_after_align;
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}
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default:
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bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag);
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}
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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if (longname) {
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file_header->name = longname;
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longname = NULL;
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}
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if (linkname) {
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file_header->link_target = linkname;
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linkname = NULL;
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}
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#endif
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if (!strncmp(file_header->name, "/../"+1, 3)
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|| strstr(file_header->name, "/../")
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) {
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bb_error_msg_and_die("name with '..' encountered: '%s'",
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file_header->name);
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}
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/* Strip trailing '/' in directories */
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/* Must be done after mode is set as '/' is used to check if it's a directory */
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cp = last_char_is(file_header->name, '/');
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if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
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archive_handle->action_header(archive_handle->file_header);
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/* Note that we kill the '/' only after action_header() */
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/* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */
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if (cp) *cp = '\0';
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archive_handle->flags |= ARCHIVE_EXTRACT_QUIET;
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archive_handle->action_data(archive_handle);
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llist_add_to(&(archive_handle->passed), file_header->name);
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} else {
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data_skip(archive_handle);
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free(file_header->name);
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}
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archive_handle->offset += file_header->size;
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free(file_header->link_target);
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/* Do not free(file_header->name)! */
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#if ENABLE_FEATURE_TAR_UNAME_GNAME
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free(file_header->uname);
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free(file_header->gname);
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#endif
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return EXIT_SUCCESS;
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}
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