diff options
Diffstat (limited to 'archival/libunarchive/get_header_tar.c')
| -rw-r--r-- | archival/libunarchive/get_header_tar.c | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c new file mode 100644 index 0000000..bf0f92b --- /dev/null +++ b/archival/libunarchive/get_header_tar.c @@ -0,0 +1,378 @@ +/* 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" + +/* NB: _DESTROYS_ str[len] character! */ +static unsigned long long getOctal(char *str, int len) +{ + unsigned long long v; + /* NB: leading spaces are allowed. Using strtoull to handle that. + * The downside is that we accept e.g. "-123" too :) + */ + str[len] = '\0'; + v = strtoull(str, &str, 8); + if (*str && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY || *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 FAST_FUNC get_header_tar(archive_handle_t *archive_handle) +{ + 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 */ + /* POSIX: "ustar" NUL "00" */ + /* GNU tar: "ustar " NUL */ + /* Normally it's defined as magic[6] followed by + * version[2], but we put them together to simplify code + */ + char magic[8]; /* 257-264 */ + 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 i, sum_u, sum; +#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY + int sum_s; +#endif + int parse_names; + + /* Our "private data" */ +#define p_end (*(smallint *)(&archive_handle->ah_priv[0])) +#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS +#define p_longname (*(char* *)(&archive_handle->ah_priv[1])) +#define p_linkname (*(char* *)(&archive_handle->ah_priv[2])) +#else +#define p_longname 0 +#define p_linkname 0 +#endif +// if (!archive_handle->ah_priv_inited) { +// archive_handle->ah_priv_inited = 1; +// p_end = 0; +// USE_FEATURE_TAR_GNU_EXTENSIONS(p_longname = NULL;) +// USE_FEATURE_TAR_GNU_EXTENSIONS(p_linkname = NULL;) +// } + + if (sizeof(tar) != 512) + BUG_tar_header_size(); + +#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS + again: +#endif + /* Align header */ + data_align(archive_handle, 512); + + again_after_align: + +#if ENABLE_DESKTOP + /* to prevent misdetection of bz2 sig */ + *(uint32_t*)(&tar) = 0; + i = full_read(archive_handle->src_fd, &tar, 512); + /* If GNU tar sees EOF in above read, it says: + * "tar: A lone zero block at N", where N = kilobyte + * where EOF was met (not EOF block, actual EOF!), + * and exits with EXIT_SUCCESS. + * We will mimic exit(EXIT_SUCCESS), although we will not mimic + * the message and we don't check whether we indeed + * saw zero block directly before this. */ + if (i == 0) { + xfunc_error_retval = 0; + short_read: + bb_error_msg_and_die("short read"); + } + if (i != 512) { + USE_FEATURE_TAR_AUTODETECT(goto autodetect;) + goto short_read; + } + +#else + i = 512; + xread(archive_handle->src_fd, &tar, i); +#endif + archive_handle->offset += i; + + /* If there is no filename its an empty header */ + if (tar.name[0] == 0 && tar.prefix[0] == 0) { + if (p_end) { + /* 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) + continue; + return EXIT_FAILURE; + } + p_end = 1; + return EXIT_SUCCESS; + } + p_end = 0; + + /* Check header has valid magic, "ustar" is for the proper tar, + * five NULs are for the old tar format */ + if (strncmp(tar.magic, "ustar", 5) != 0 + && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY + || memcmp(tar.magic, "\0\0\0\0", 5) != 0) + ) { +#if ENABLE_FEATURE_TAR_AUTODETECT + char FAST_FUNC (*get_header_ptr)(archive_handle_t *); + + USE_DESKTOP(autodetect:) + /* tar gz/bz autodetect: check for gz/bz2 magic. + * If we see the magic, and it is the very first block, + * we can switch to get_header_tar_gz/bz2/lzma(). + * Needs seekable fd. I wish recv(MSG_PEEK) works + * on any fd... */ +#if ENABLE_FEATURE_SEAMLESS_GZ + if (tar.name[0] == 0x1f && tar.name[1] == (char)0x8b) { /* gzip */ + get_header_ptr = get_header_tar_gz; + } else +#endif +#if ENABLE_FEATURE_SEAMLESS_BZ2 + if (tar.name[0] == 'B' && tar.name[1] == 'Z' + && tar.name[2] == 'h' && isdigit(tar.name[3]) + ) { /* bzip2 */ + get_header_ptr = get_header_tar_bz2; + } else +#endif + goto err; + /* Two different causes for lseek() != 0: + * unseekable fd (would like to support that too, but...), + * or not first block (false positive, it's not .gz/.bz2!) */ + if (lseek(archive_handle->src_fd, -i, SEEK_CUR) != 0) + goto err; + while (get_header_ptr(archive_handle) == EXIT_SUCCESS) + continue; + return EXIT_FAILURE; + err: +#endif /* FEATURE_TAR_AUTODETECT */ + bb_error_msg_and_die("invalid tar magic"); + } + + /* Do checksum on headers. + * POSIX says that checksum is done on unsigned bytes, but + * Sun and HP-UX gets it wrong... more details in + * GNU tar source. */ +#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY + sum_s = ' ' * sizeof(tar.chksum); +#endif + sum_u = ' ' * sizeof(tar.chksum); + for (i = 0; i < 148; i++) { + sum_u += ((unsigned char*)&tar)[i]; +#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY + sum_s += ((signed char*)&tar)[i]; +#endif + } + for (i = 156; i < 512; i++) { + sum_u += ((unsigned char*)&tar)[i]; +#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY + sum_s += ((signed char*)&tar)[i]; +#endif + } +#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY + sum = strtoul(tar.chksum, &cp, 8); + if ((*cp && *cp != ' ') + || (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) + ) { + bb_error_msg_and_die("invalid tar header checksum"); + } +#else + /* This field does not need special treatment (getOctal) */ + sum = xstrtoul(tar.chksum, 8); + if (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) { + bb_error_msg_and_die("invalid tar header checksum"); + } +#endif + + /* 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]) { + char t = tar.prefix[0]; + /* we trash prefix[0] here, but we DO need it later! */ + unsigned minor = GET_OCTAL(tar.devminor); + unsigned major = GET_OCTAL(tar.devmajor); + file_header->device = makedev(major, minor); + tar.prefix[0] = t; + } + file_header->link_target = NULL; + if (!p_linkname && parse_names && tar.linkname[0]) { + file_header->link_target = xstrndup(tar.linkname, sizeof(tar.linkname)); + /* FIXME: what if we have non-link object with link_target? */ + /* Will link_target be free()ed? */ + } +#if ENABLE_FEATURE_TAR_UNAME_GNAME + file_header->uname = tar.uname[0] ? xstrndup(tar.uname, sizeof(tar.uname)) : NULL; + file_header->gname = tar.gname[0] ? xstrndup(tar.gname, sizeof(tar.gname)) : NULL; +#endif + 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 (!p_longname && parse_names) { + /* we trash mode[0] here, it's ok */ + //tar.name[sizeof(tar.name)] = '\0'; - gcc 4.3.0 would complain + tar.mode[0] = '\0'; + if (tar.prefix[0]) { + /* and padding[0] */ + //tar.prefix[sizeof(tar.prefix)] = '\0'; - gcc 4.3.0 would complain + tar.padding[0] = '\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, '/')) { + goto set_dir; + } +#endif + file_header->mode |= S_IFREG; + break; + case '2': + file_header->mode |= S_IFLNK; + /* have seen tarballs with size field containing + * the size of the link target's name */ + size0: + file_header->size = 0; + break; + case '3': + file_header->mode |= S_IFCHR; + goto size0; /* paranoia */ + case '4': + file_header->mode |= S_IFBLK; + goto size0; + case '5': + USE_FEATURE_TAR_OLDGNU_COMPATIBILITY(set_dir:) + file_header->mode |= S_IFDIR; + goto size0; + case '6': + file_header->mode |= S_IFIFO; + goto size0; +#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS + case 'L': + /* free: paranoia: tar with several consecutive longnames */ + free(p_longname); + /* For paranoia reasons we allocate extra NUL char */ + p_longname = xzalloc(file_header->size + 1); + /* We read ASCIZ string, including NUL */ + xread(archive_handle->src_fd, p_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(p_linkname); + p_linkname = xzalloc(file_header->size + 1); + xread(archive_handle->src_fd, p_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 (p_longname) { + file_header->name = p_longname; + p_longname = NULL; + } + if (p_linkname) { + file_header->link_target = p_linkname; + p_linkname = NULL; + } +#endif + if (strncmp(file_header->name, "/../"+1, 3) == 0 + || 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->ah_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_target); + /* Do not free(file_header->name)! (why?) */ +#if ENABLE_FEATURE_TAR_UNAME_GNAME + free(file_header->uname); + free(file_header->gname); +#endif + return EXIT_SUCCESS; +} |