Modified so that it "works" for archs other than i386... arm in particular.

Also tried to clean up the logic a little, and ensure that read errors
or invalid archives resulted in error returns.  This could use a lot more
work... Volunteers?

1 files changed, 108 insertions, 47 deletions

diff --git a/archival/libunarchive/get_header_zip.c b/archival/libunarchive/get_header_zip.c
index 84f2a54f2..5fa3a6c8c 100644
--- a/archival/libunarchive/get_header_zip.c
+++ b/archival/libunarchive/get_header_zip.c
@@ -19,92 +19,153 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 
+#include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "unarchive.h"
 #include "libbb.h"
 
-#define ZIP_FILEHEADER_MAGIC 0x04034b50
-#define ZIP_CDS_MAGIC 0x02014b50
-#define ZIP_CDS_END_MAGIC 0x06054b50
-#define ZIP_DD_MAGIC 0x8074b50
+#define ZIP_FILEHEADER_MAGIC	0x04034b50
+#define ZIP_CDS_MAGIC			0x02014b50
+#define ZIP_CDS_END_MAGIC		0x06054b50
+#define ZIP_DD_MAGIC			0x08074b50
+
+
+enum {
+	zh_version,
+	zh_flags,
+	zh_method,
+	zh_modtime,
+	zh_moddate,
+	zh_crc32,
+	zh_cmpsize,
+	zh_ucmpsize,
+	zh_filename_len,
+	zh_extra_len
+};
+
+static const char fail_msg[] = "Invalid file or read error";
+
+static int le_read_int(FILE *fp, int n)
+{
+	int r = 0;
+	int s = 1;
+	int c;
+
+	archive_offset += n;
+
+	do {
+		if ((c = fgetc(fp)) == EOF) {
+			error_msg_and_die(fail_msg);
+		}
+		r += s * c;
+		s <<= 8;
+	} while (--n);
+
+	return r;
+}
+
+static void read_header(FILE *fp, int *zh)
+{
+	static const char s[] = { 2, 2, 2, 2, 2, 4, 4, 4, 2, 2, 0 };
+	int i = 0;
+
+	do {
+		zh[i] = le_read_int(fp, s[i]);
+	} while (s[++i]);
+}
 
 file_header_t *get_header_zip(FILE *zip_stream)
 {
-	struct {
-		short version __attribute__ ((packed));
-		short flags __attribute__ ((packed));
-		short method __attribute__ ((packed));
-		short modtime __attribute__ ((packed));
-		short moddate __attribute__ ((packed));
-		int crc32 __attribute__ ((packed));
-		int cmpsize __attribute__ ((packed));
-		int ucmpsize __attribute__ ((packed));
-		short filename_len __attribute__ ((packed));
-		short extra_len __attribute__ ((packed));
-	} zip_header;
+	int zip_header[10];
 	file_header_t *zip_entry = NULL;
-	int magic;
-	static int dd_ahead = 0; // If this is true, the we didn't know how long the last extraced file was
+	int magic, tmpmagic;
+	/* If dd_ahead is true, we didn't know the last extracted file's length. */
+	static int dd_ahead = 0;
 
-	fread (&magic, 4, 1, zip_stream);
-	archive_offset += 4;
+	magic = le_read_int(zip_stream, 4);
 
-	if (feof(zip_stream)) return(NULL);
-checkmagic:
+ checkmagic:
 	switch (magic) {
 		case ZIP_FILEHEADER_MAGIC:
 			zip_entry = xcalloc(1, sizeof(file_header_t));
-			fread (&zip_header, sizeof(zip_header), 1, zip_stream);
-			archive_offset += sizeof(zip_header);
-			if (!(zip_header.method == 8 || zip_header.method == 0)) { printf("Unsupported compression method %d\n", zip_header.method); return(NULL); }
-			zip_entry->name = calloc(zip_header.filename_len + 1, sizeof(char));
-			fread (zip_entry->name, sizeof(char), zip_header.filename_len, zip_stream);
-			archive_offset += zip_header.filename_len;
-			seek_sub_file(zip_stream, zip_header.extra_len);
-			zip_entry->size = zip_header.cmpsize;
-			if (zip_header.method == 8) zip_entry->extract_func = &inflate;
+
+			read_header(zip_stream, zip_header);
+
+			if (zip_header[zh_method] == 8) {
+				zip_entry->extract_func = &inflate;
+			} else if (zip_header[zh_method] != 0) {
+				error_msg_and_die("Unsupported compression method %d\n",
+								  zip_header[zh_method]);
+			}
+
+			zip_entry->name = xmalloc(zip_header[zh_filename_len] + 1);
+			if (!fread(zip_entry->name, zip_header[zh_filename_len], 1, zip_stream)) {
+				error_msg_and_die(fail_msg);
+			}
+			archive_offset += zip_header[zh_filename_len];
+
+			seek_sub_file(zip_stream, zip_header[zh_extra_len]);
+
+			zip_entry->size = zip_header[zh_cmpsize];
+
 			zip_entry->mode = S_IFREG | 0777;
-			// Time/Date?
-			if (*(zip_entry->name + strlen(zip_entry->name) - 1) == '/') { // Files that end in a / are directories
+
+			/* Time/Date? */
+
+			zip_entry->name[zip_header[zh_filename_len]] = 0;
+			if (*(zip_entry->name + zip_header[zh_filename_len] - 1) == '/') {
+				/* Files that end in a / are directories */
+				/* Remove trailing / so unarchive doesn't get confused */
+				*(zip_entry->name + zip_header[zh_filename_len] - 1) = '\0';
 				zip_entry->mode ^= S_IFREG;
 				zip_entry->mode |= S_IFDIR;
-				*(zip_entry->name + strlen(zip_entry->name) - 1) = '\0'; // Remove trailing / so unarchive doesn't get confused
 			}
-			//printf("cmpsize: %d, ucmpsize: %d, method: %d\n", zip_header.cmpsize, zip_header.ucmpsize, zip_header.method);
-			if (zip_header.flags & 0x8) { // crc32, and sizes are in the data description _after_ the file
-				if (zip_header.cmpsize == 0) dd_ahead = 1; // As we don't know how long this file it is difficult to skip! but it is compressed, so normally its ok
-				if (zip_header.ucmpsize != 0) dd_ahead = 2; // Humm... we would otherwise skip this twice - not good!
+
+			if (zip_header[zh_flags] & 0x8) {
+				/* crc32, and sizes are in the data description _after_ the file */
+				if (zip_header[zh_cmpsize] == 0) {
+					/* As we don't know how long this file it is difficult to skip!
+					 * but it is compressed, so normally its ok */
+					dd_ahead = 1;
+				}
+				if (zip_header[zh_ucmpsize] != 0) {
+					/* Humm... we would otherwise skip this twice - not good! */
+					dd_ahead = 2;
+				}
 			}
 			break;
+
 		case ZIP_CDS_MAGIC: /* FALLTHRU */
 		case ZIP_CDS_END_MAGIC:
 			return(NULL);
 			break;
+
 		case ZIP_DD_MAGIC: {
 			int cmpsize;
 			seek_sub_file(zip_stream, 4); // Skip crc32
-			fread(&cmpsize, 4, 1, zip_stream);
-			archive_offset += 4;
+			cmpsize = le_read_int(zip_stream, 4);
 			if (dd_ahead == 1) archive_offset += cmpsize;
 			seek_sub_file(zip_stream, 4); // Skip uncompressed size
 			dd_ahead = 0;
 			return (get_header_zip(zip_stream));
 			break; }
+
 		default:
 			if (!dd_ahead) error_msg("Invalid magic (%#x): Trying to skip junk", magic);
 			dd_ahead = 0;
-			while (!feof(zip_stream)) {
-				int tmpmagic;
-				tmpmagic = fgetc(zip_stream);
+			while ((tmpmagic = fgetc(zip_stream)) != EOF) {
 				archive_offset++;
 				magic = ((magic >> 8) & 0x00ffffff) | ((tmpmagic << 24) & 0xff000000);
-				if (magic == ZIP_FILEHEADER_MAGIC || magic == ZIP_CDS_MAGIC || magic == ZIP_CDS_END_MAGIC) goto checkmagic;
+				if (magic == ZIP_FILEHEADER_MAGIC
+					|| magic == ZIP_CDS_MAGIC
+					|| magic == ZIP_CDS_END_MAGIC) {
+					goto checkmagic;
+				}
 			}
-			error_msg("End of archive reached: Bad archive");
-			return(NULL);
+			error_msg_and_die(fail_msg);
 	}
-	//if (archive_offset != ftell(zip_stream)) printf("Archive offset out of sync (%d,%d)\n", (int) archive_offset, (int) ftell(zip_stream));
+
 	return(zip_entry);
 }