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);
 }