7zip: Check skip in setup_decode_folder

Make sure that all bytes are actually skipped. Normally, the result can
be ignored because the bytes were read previously. Here, more bytes than
previously read will be skipped.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>

diff --git a/libarchive/archive_read_support_format_7zip.c b/libarchive/archive_read_support_format_7zip.c
index 202c1d8c4cf56fcb0e61492011dc8e8f1fbad777..e4f528d86a52114dc9b24ef5ab6275ff688829c0 100644 (file)
--- a/libarchive/archive_read_support_format_7zip.c
+++ b/libarchive/archive_read_support_format_7zip.c
@@ -468,7 +468,7 @@ static int  read_SubStreamsInfo(struct archive_read *,
                    struct _7z_substream_info *, struct _7z_folder *, size_t);
 static int     read_Times(struct archive_read *, struct _7z_header_info *,
                    int);
-static void    read_consume(struct archive_read *);
+static int     read_consume(struct archive_read *);
 static ssize_t read_stream(struct archive_read *, const void **, size_t,
                    size_t);
 static int     seek_pack(struct archive_read *);
@@ -1249,16 +1249,23 @@ archive_read_format_7zip_cleanup(struct archive_read *a)
        return (ARCHIVE_OK);
 }
 
-static void
+static int
 read_consume(struct archive_read *a)
 {
        struct _7zip *zip = (struct _7zip *)a->format->data;
 
        if (zip->pack_stream_bytes_unconsumed) {
-               __archive_read_consume(a, zip->pack_stream_bytes_unconsumed);
+               int64_t r;
+
+               if ((r = __archive_read_consume(a,
+                   zip->pack_stream_bytes_unconsumed)) < 0)
+                       return ((int)r);
+
                zip->stream_offset += zip->pack_stream_bytes_unconsumed;
                zip->pack_stream_bytes_unconsumed = 0;
        }
+
+       return (ARCHIVE_OK);
 }
 
 #ifdef HAVE_LZMA_H
@@ -3990,7 +3997,8 @@ setup_decode_folder(struct archive_read *a, struct _7z_folder *folder,
                        return (r);
                zip->pack_stream_bytes_unconsumed =
                    zip->pack_stream_inbytes_remaining;
-               read_consume(a);
+               if ((r = read_consume(a)) < 0)
+                       return (r);
 
                /* Read following three sub streams. */
                for (i = 0; i < 3; i++) {