diff options
Diffstat (limited to 'archival/libunarchive/get_header_tar.c')
| -rw-r--r-- | archival/libunarchive/get_header_tar.c | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c new file mode 100644 index 000000000..66c3314a1 --- /dev/null +++ b/archival/libunarchive/get_header_tar.c @@ -0,0 +1,275 @@ +/* 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 its 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; +} |