X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=archival%2Flibunarchive%2Fget_header_tar.c;h=beb8687c72ac3f0bc42ba7a51f36eeff064e6180;hb=714701c890b5f03253c5ecdb7367c4258ce78715;hp=5354af8d7e4b999820c0d68849a0ce3edb6fe9f2;hpb=f074afc2a0c5946544fc15da15733467e7c585f5;p=oweals%2Fbusybox.git

diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c
index 5354af8d7..beb8687c7 100644
--- a/archival/libunarchive/get_header_tar.c
+++ b/archival/libunarchive/get_header_tar.c
@@ -1,131 +1,180 @@
-/*
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
+/* vi: set sw=4 ts=4: */
+/* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU Library General Public License for more 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
  *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *  References:
+ *    GNU tar and star man pages,
+ *    Opengroup's ustar interchange format,
+ *	http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
  */
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include "unarchive.h"
 #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
 
-extern char get_header_tar(archive_handle_t *archive_handle)
+/* 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;
-	union {
+	struct {
 		/* ustar header, Posix 1003.1 */
-		unsigned char raw[512];
-		struct {
-			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 */
-		} formated;
+		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;
-	long sum = 0;
-	long i;
+	char *cp;
+	int sum, i;
+	int parse_names;
+
+	if (sizeof(tar) != 512)
+		BUG_tar_header_size();
+ again:
 
 	/* Align header */
 	data_align(archive_handle, 512);
 
-	if (archive_xread(archive_handle, tar.raw, 512) != 512) {
-		/* Assume end of file */
-		return(EXIT_FAILURE);
-	}
+ 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.formated.name[0] == 0) {
-		return(EXIT_SUCCESS);
+	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.formated.magic, "ustar", 5) != 0) {
-#ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
-		if (strncmp(tar.formated.magic, "\0\0\0\0\0", 5) != 0)
+	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");
+			bb_error_msg_and_die("invalid tar magic");
 	}
 	/* Do checksum on headers */
-	for (i =  0; i < 148 ; i++) {
-		sum += tar.raw[i];
+	sum = ' ' * sizeof(tar.chksum);
+	for (i = 0; i < 148 ; i++) {
+		sum += ((char*)&tar)[i];
 	}
-	sum += ' ' * 8;
-	for (i =  156; i < 512 ; i++) {
-		sum += tar.raw[i];
+	for (i = 156; i < 512 ; i++) {
+		sum += ((char*)&tar)[i];
 	}
-	if (sum != strtol(tar.formated.chksum, NULL, 8)) {
-		bb_error_msg("Invalid tar header checksum");
-		return(EXIT_FAILURE);
+	/* This field does not need special treatment (getOctal) */
+	if (sum != xstrtoul(tar.chksum, 8)) {
+		bb_error_msg_and_die("invalid tar header checksum");
 	}
 
-#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
-	if (longname) {
-		file_header->name = longname;
-		longname = NULL;
+	/* 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);
 	}
-	else if (linkname) {
-		file_header->name = linkname;
-		linkname = NULL;
-	} else
-#endif
-	if (tar.formated.prefix[0] == 0) {
-		file_header->name = strdup(tar.formated.name);
-	} else {
-		file_header->name = concat_path_file(tar.formated.prefix, tar.formated.name);
+	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->mode = strtol(tar.formated.mode, NULL, 8);
-	file_header->uid = strtol(tar.formated.uid, NULL, 8);
-	file_header->gid = strtol(tar.formated.gid, NULL, 8);
-	file_header->size = strtol(tar.formated.size, NULL, 8);
-	file_header->mtime = strtol(tar.formated.mtime, NULL, 8);
-	file_header->link_name = (tar.formated.linkname[0] != '\0') ? 
-	    bb_xstrdup(tar.formated.linkname) : NULL;
-	file_header->device = (dev_t) ((strtol(tar.formated.devmajor, NULL, 8) << 8) +
-				 strtol(tar.formated.devminor, NULL, 8));
-
-	/* Fix mode, used by the old format */
-	switch (tar.formated.typeflag) {
-# ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
-	case 0:
+	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 {
-			file_header->mode |= S_IFREG;
-		}
+		} else
+#endif
+		file_header->mode |= S_IFREG;
 		break;
 	case '2':
 		file_header->mode |= S_IFLNK;
@@ -142,50 +191,85 @@ extern char get_header_tar(archive_handle_t *archive_handle)
 	case '6':
 		file_header->mode |= S_IFIFO;
 		break;
-# endif
-	/* hard links are detected as entries with 0 size, a link name, 
-	 * and not being a symlink, hence we have nothing to do here */
-	case '1':
-		file_header->mode |= ~S_IFLNK;
-		break;
-# ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
-	case 'L': {
-			longname = xmalloc(file_header->size + 1);
-			archive_xread_all(archive_handle, longname, file_header->size);
-			longname[file_header->size] = '\0';
-			archive_handle->offset += file_header->size;
-
-			return(get_header_tar(archive_handle));
-		}
-	case 'K': {
-			linkname = xmalloc(file_header->size + 1);
-			archive_xread_all(archive_handle, linkname, file_header->size);
-			linkname[file_header->size] = '\0';
-			archive_handle->offset += file_header->size;
-
-			file_header->name = linkname;
-			return(get_header_tar(archive_handle));
-		}
-	case 'D':
-	case 'M':
-	case 'N':
-	case 'S':
-	case 'V':
-		bb_error_msg("Ignoring GNU extension type %c", tar.formated.typeflag);
-# endif
+#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 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->flags |= ARCHIVE_EXTRACT_QUIET;
 		archive_handle->action_data(archive_handle);
-		archive_handle->passed = llist_add_to(archive_handle->passed, file_header->name);
+		llist_add_to(&(archive_handle->passed), file_header->name);
 	} else {
-		data_skip(archive_handle);			
+		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);
+	return EXIT_SUCCESS;
 }