tar: correctly skip (and warn about) pax headers.
plug memory leak. save 50 bytes.
Wooohooo! we finally can unpack kernel tarballs!
diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c
index b785d63..583f6f8 100644
--- a/archival/libunarchive/get_header_tar.c
+++ b/archival/libunarchive/get_header_tar.c
@@ -40,11 +40,12 @@
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 = 0;
+ static int end;
file_header_t *file_header = archive_handle->file_header;
struct {
@@ -69,18 +70,17 @@
} tar;
char *cp;
int sum, i;
-#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
int parse_names;
-#else
- enum { parse_names = 1 };
-#endif
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;
@@ -121,13 +121,12 @@
bb_error_msg_and_die("invalid tar header checksum");
}
-#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
- parse_names = (tar.typeflag != 'L' && tar.typeflag != 'K');
-#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 */
-#define GET_OCTAL(a) getOctal((a), sizeof(a))
if (tar.devmajor[0]) {
unsigned minor = GET_OCTAL(tar.devminor);
unsigned major = GET_OCTAL(tar.devmajor);
@@ -147,8 +146,8 @@
file_header->uid = GET_OCTAL(tar.uid);
/* Set bits 0-11 of the files mode */
file_header->mode = 07777 & GET_OCTAL(tar.mode);
-#undef GET_OCTAL
+ file_header->name = NULL;
if (!longname && parse_names) {
/* we trash mode[0] here, it's ok */
tar.name[sizeof(tar.name)] = '\0';
@@ -158,6 +157,7 @@
file_header->name = concat_path_file(tar.prefix, tar.name);
} else
file_header->name = xstrdup(tar.name);
+ /* FIXME: add check for /../ attacks */
}
/* Set bits 12-15 of the files mode */
@@ -168,8 +168,7 @@
file_header->mode |= S_IFREG;
break;
case '7':
- /* Reserved for high performance files, treat as normal file */
- case 0:
+ /* case 0: */
case '0':
#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
if (last_char_is(file_header->name, '/')) {
@@ -195,18 +194,24 @@
break;
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
case 'L':
- /* paranoia: tar with several consecutive longnames */
+ /* 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);
+ /* 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);
+ /* 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 */
@@ -214,11 +219,19 @@
case 'V': /* Volume header */
#endif
case 'g': /* pax global header */
- case 'x': /* pax extended header */
- bb_error_msg("ignoring extension type %c", tar.typeflag);
- break;
+ 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("unknown typeflag: 0x%x", tar.typeflag);
+ bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag);
}
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
@@ -246,10 +259,12 @@
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;
}