| /* 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" |
| |
| typedef uint32_t aliased_uint32_t FIX_ALIASING; |
| typedef off_t aliased_off_t FIX_ALIASING; |
| |
| |
| /* NB: _DESTROYS_ str[len] character! */ |
| static unsigned long long getOctal(char *str, int len) |
| { |
| unsigned long long v; |
| char *end; |
| /* 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, &end, 8); |
| /* std: "Each numeric field is terminated by one or more |
| * <space> or NUL characters". We must support ' '! */ |
| if (*end != '\0' && *end != ' ') { |
| int8_t first = str[0]; |
| if (!(first & 0x80)) |
| bb_error_msg_and_die("corrupted octal value in tar header"); |
| /* |
| * GNU tar uses "base-256 encoding" for very large numbers. |
| * Encoding is binary, with highest bit always set as a marker |
| * and sign in next-highest bit: |
| * 80 00 .. 00 - zero |
| * bf ff .. ff - largest positive number |
| * ff ff .. ff - minus 1 |
| * c0 00 .. 00 - smallest negative number |
| * |
| * Example of tar file with 8914993153 (0x213600001) byte file. |
| * Field starts at offset 7c: |
| * 00070 30 30 30 00 30 30 30 30 30 30 30 00 80 00 00 00 |000.0000000.....| |
| * 00080 00 00 00 02 13 60 00 01 31 31 31 32 30 33 33 36 |.....`..11120336| |
| * |
| * NB: tarballs with NEGATIVE unix times encoded that way were seen! |
| */ |
| v = first; |
| /* Sign-extend using 6th bit: */ |
| v <<= sizeof(unsigned long long)*8 - 7; |
| v = (long long)v >> (sizeof(unsigned long long)*8 - 7); |
| while (--len != 0) |
| v = (v << 8) + (unsigned char) *str++; |
| } |
| return v; |
| } |
| #define GET_OCTAL(a) getOctal((a), sizeof(a)) |
| |
| #if ENABLE_FEATURE_TAR_SELINUX |
| /* Scan a PAX header for SELinux contexts, via "RHT.security.selinux" keyword. |
| * This is what Red Hat's patched version of tar uses. |
| */ |
| # define SELINUX_CONTEXT_KEYWORD "RHT.security.selinux" |
| static char *get_selinux_sctx_from_pax_hdr(archive_handle_t *archive_handle, unsigned sz) |
| { |
| char *buf, *p; |
| char *result; |
| |
| p = buf = xmalloc(sz + 1); |
| /* prevent bb_strtou from running off the buffer */ |
| buf[sz] = '\0'; |
| xread(archive_handle->src_fd, buf, sz); |
| archive_handle->offset += sz; |
| |
| result = NULL; |
| while (sz != 0) { |
| char *end, *value; |
| unsigned len; |
| |
| /* Every record has this format: "LEN NAME=VALUE\n" */ |
| len = bb_strtou(p, &end, 10); |
| /* expect errno to be EINVAL, because the character |
| * following the digits should be a space |
| */ |
| p += len; |
| sz -= len; |
| if ((int)sz < 0 |
| || len == 0 |
| || errno != EINVAL |
| || *end != ' ' |
| ) { |
| bb_error_msg("malformed extended header, skipped"); |
| // More verbose version: |
| //bb_error_msg("malformed extended header at %"OFF_FMT"d, skipped", |
| // archive_handle->offset - (sz + len)); |
| break; |
| } |
| /* overwrite the terminating newline with NUL |
| * (we do not bother to check that it *was* a newline) |
| */ |
| p[-1] = '\0'; |
| /* Is it selinux security context? */ |
| value = end + 1; |
| if (strncmp(value, SELINUX_CONTEXT_KEYWORD"=", sizeof(SELINUX_CONTEXT_KEYWORD"=") - 1) == 0) { |
| value += sizeof(SELINUX_CONTEXT_KEYWORD"=") - 1; |
| result = xstrdup(value); |
| break; |
| } |
| } |
| |
| free(buf); |
| return result; |
| } |
| #endif |
| |
| char FAST_FUNC get_header_tar(archive_handle_t *archive_handle) |
| { |
| file_header_t *file_header = archive_handle->file_header; |
| struct tar_header_t tar; |
| char *cp; |
| int i, sum_u, sum; |
| #if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY |
| int sum_s; |
| #endif |
| int parse_names; |
| |
| /* Our "private data" */ |
| #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
| # define p_longname (archive_handle->tar__longname) |
| # define p_linkname (archive_handle->tar__linkname) |
| #else |
| # define p_longname 0 |
| # define p_linkname 0 |
| #endif |
| |
| #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS || ENABLE_FEATURE_TAR_SELINUX |
| again: |
| #endif |
| /* Align header */ |
| data_align(archive_handle, 512); |
| |
| again_after_align: |
| |
| #if ENABLE_DESKTOP || ENABLE_FEATURE_TAR_AUTODETECT |
| /* to prevent misdetection of bz2 sig */ |
| *(aliased_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) { |
| IF_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 (archive_handle->tar__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; |
| } |
| archive_handle->tar__end = 1; |
| return EXIT_SUCCESS; |
| } |
| archive_handle->tar__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 *); |
| |
| 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 |
| # if ENABLE_FEATURE_SEAMLESS_XZ |
| //TODO |
| # 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 |
| } |
| /* This field does not need special treatment (getOctal) */ |
| { |
| char *endp; /* gcc likes temp var for &endp */ |
| sum = strtoul(tar.chksum, &endp, 8); |
| if ((*endp != '\0' && *endp != ' ') |
| || (sum_u != sum IF_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) |
| ) { |
| bb_error_msg_and_die("invalid tar header checksum"); |
| } |
| } |
| /* don't use xstrtoul, tar.chksum may have leading spaces */ |
| sum = strtoul(tar.chksum, NULL, 8); |
| if (sum_u != sum IF_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) { |
| 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]) { |
| 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->tar__uname = tar.uname[0] ? xstrndup(tar.uname, sizeof(tar.uname)) : NULL; |
| file_header->tar__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': |
| IF_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 |
| #if !ENABLE_FEATURE_TAR_SELINUX |
| case 'g': /* pax global header */ |
| case 'x': /* pax extended header */ |
| #else |
| skip_ext_hdr: |
| #endif |
| { |
| 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; |
| } |
| #if ENABLE_FEATURE_TAR_SELINUX |
| case 'g': /* pax global header */ |
| case 'x': { /* pax extended header */ |
| char **pp; |
| if ((uoff_t)file_header->size > 0xfffff) /* paranoia */ |
| goto skip_ext_hdr; |
| pp = (tar.typeflag == 'g') ? &archive_handle->tar__global_sctx : &archive_handle->tar__next_file_sctx; |
| free(*pp); |
| *pp = get_selinux_sctx_from_pax_hdr(archive_handle, file_header->size); |
| goto again; |
| } |
| #endif |
| 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->action_data(archive_handle); |
| if (archive_handle->accept || archive_handle->reject) |
| llist_add_to(&archive_handle->passed, file_header->name); |
| else /* Caller isn't interested in list of unpacked files */ |
| free(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)! |
| * It might be inserted in archive_handle->passed - see above */ |
| #if ENABLE_FEATURE_TAR_UNAME_GNAME |
| free(file_header->tar__uname); |
| free(file_header->tar__gname); |
| #endif |
| return EXIT_SUCCESS; |
| } |