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tar: fix and sanitize handling of long filenames/linknames

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(GNU extensions 'K' and 'L').
We correctly handle them when untarring now, but unfortunately
we still don't use them when tarring! That stupid 100 char limit
is still there!
The biggest problem is that we don't support 'pax' tar format.
Linux kernel tarballs are in this format... shame
This commit is contained in:
Denis Vlasenko 2006-11-24 17:21:44 +00:00
parent d398ecab9d
commit d6772501db
3 changed files with 47 additions and 21 deletions
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2
archival/libunarchive/get_header_ar.c
View File

@ -88,7 +88,7 @@ char get_header_ar(archive_handle_t *archive_handle)
#endif
} else {
/* short filenames */
typed->name = xstrndup(ar.formatted.name, 16);
typed->name = xstrndup(ar.formatted.name, 16);
}
typed->name[strcspn(typed->name, " /")] = '\0';

65
archival/libunarchive/get_header_tar.c
View File

@ -14,9 +14,14 @@
#include "libbb.h"
#include "unarchive.h"
#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
static char *longname = NULL;
static char *linkname = NULL;
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
static char *longname;
static char *linkname;
#else
enum {
longname = 0,
linkname = 0,
};
#endif
/* NB: _DESTROYS_ str[len] character! */
@ -64,6 +69,11 @@ char get_header_tar(archive_handle_t *archive_handle)
} tar;
char *cp;
int sum, i;
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
int parse_names;
#else
enum { parse_names = 0 };
#endif
if (sizeof(tar) != 512)
BUG_tar_header_size();
@ -93,7 +103,7 @@ char get_header_tar(archive_handle_t *archive_handle)
* 0's are for the old tar format
*/
if (strncmp(tar.magic, "ustar", 5) != 0) {
#ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATIBILITY
#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");
@ -111,6 +121,10 @@ char get_header_tar(archive_handle_t *archive_handle)
bb_error_msg_and_die("invalid tar header checksum");
}
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
parse_names = (tar.typeflag != 'L' && tar.typeflag != 'K');
#endif
/* getOctal trashes subsequent field, therefore we call it
* on fields in reverse order */
#define GET_OCTAL(a) getOctal((a), sizeof(a))
@ -119,27 +133,24 @@ char get_header_tar(archive_handle_t *archive_handle)
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);
file_header->link_name = !tar.linkname[0] ? NULL :
xstrndup(tar.linkname, sizeof(tar.linkname));
/* Set bits 0-11 of the files mode */
file_header->mode = 07777 & GET_OCTAL(tar.mode);
#undef GET_OCTAL
#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
if (longname) {
file_header->name = longname;
longname = NULL;
}
else if (linkname) {
file_header->name = linkname;
linkname = NULL;
} else
#endif
{ /* we trash mode[0] here, it's ok */
if (!longname && parse_names) {
/* we trash mode[0] here, it's ok */
tar.name[sizeof(tar.name)] = '\0';
if (tar.prefix[0])
file_header->name = concat_path_file(tar.prefix, tar.name);
@ -148,6 +159,7 @@ char get_header_tar(archive_handle_t *archive_handle)
}
/* 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':
@ -157,7 +169,7 @@ char get_header_tar(archive_handle_t *archive_handle)
/* Reserved for high performance files, treat as normal file */
case 0:
case '0':
#ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATIBILITY
#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
if (last_char_is(file_header->name, '/')) {
file_header->mode |= S_IFDIR;
} else
@ -179,17 +191,19 @@ char get_header_tar(archive_handle_t *archive_handle)
case '6':
file_header->mode |= S_IFIFO;
break;
#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
case 'L':
/* paranoia: tar with several consecutive longnames */
free(longname);
longname = xzalloc(file_header->size + 1);
xread(archive_handle->src_fd, longname, file_header->size);
archive_handle->offset += file_header->size;
return get_header_tar(archive_handle);
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;
file_header->name = linkname;
return get_header_tar(archive_handle);
case 'D': /* GNU dump dir */
case 'M': /* Continuation of multi volume archive */
@ -205,6 +219,17 @@ char get_header_tar(archive_handle_t *archive_handle)
bb_error_msg("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
/* 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, '/');

1
libbb/xfuncs.c
View File

@ -74,6 +74,7 @@ char * xstrndup(const char *s, int n)
if (ENABLE_DEBUG && s == NULL)
bb_error_msg_and_die("xstrndup bug");
/* TODO: think about xstrndup("abc", 10000)!!! */
t = xmalloc(++n);
return safe_strncpy(t,s,n);