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Diffstat (limited to 'archival/libarchive/get_header_tar.c')
-rw-r--r--archival/libarchive/get_header_tar.c461
1 files changed, 461 insertions, 0 deletions
diff --git a/archival/libarchive/get_header_tar.c b/archival/libarchive/get_header_tar.c
new file mode 100644
index 0000000..78b0ae2
--- /dev/null
+++ b/archival/libarchive/get_header_tar.c
@@ -0,0 +1,461 @@
+/* vi: set sw=4 ts=4: */
+/* Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ *
+ * 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 "archive.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 *);
+ uint16_t magic2;
+
+ autodetect:
+ magic2 = *(uint16_t*)tar.name;
+ /* 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 (magic2 == GZIP_MAGIC) {
+ get_header_ptr = get_header_tar_gz;
+ } else
+# endif
+# if ENABLE_FEATURE_SEAMLESS_BZ2
+ if (magic2 == BZIP2_MAGIC
+ && tar.name[2] == 'h' && isdigit(tar.name[3])
+ ) { /* bzip2 */
+ get_header_ptr = get_header_tar_bz2;
+ } else
+# endif
+# if ENABLE_FEATURE_SEAMLESS_XZ
+ //TODO: if (magic2 == XZ_MAGIC1)...
+ //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
+ }
+ /* 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;
+}