@@ -1360,15 +1360,22 @@ static int open_file(BDRVVVFATState* s,mapping_t* mapping)
{
if(!mapping)
return -1;
+ int new_path = 1;
if(!s->current_mapping ||
- strcmp(s->current_mapping->path,mapping->path)) {
- /* open file */
- int fd = qemu_open_old(mapping->path,
+ s->current_mapping->first_mapping_index!=mapping->first_mapping_index ||
+ (new_path = strcmp(s->current_mapping->path,mapping->path))) {
+
+ if (new_path) {
+ /* open file */
+ int fd = qemu_open_old(mapping->path,
O_RDONLY | O_BINARY | O_LARGEFILE);
- if(fd<0)
- return -1;
- vvfat_close_current_file(s);
- s->current_fd = fd;
+ if(fd<0)
+ return -1;
+ vvfat_close_current_file(s);
+
+ s->current_fd = fd;
+ }
+ assert(s->current_fd);
s->current_mapping = mapping;
}
return 0;
When reading with `read_cluster` we get the `mapping` with `find_mapping_for_cluster` and then we call `open_file` for this mapping. The issue appear when its the same file, but a second cluster that is not immediately after it, imagine clusters `500 -> 503`, this will give us 2 mappings one has the range `500..501` and another `503..504`, both point to the same file, but different offsets. When we don't open the file since the path is the same, we won't assign `s->current_mapping` and thus accessing way out of bound of the file. From our example above, after `open_file` (that didn't open anything) we will get the offset into the file with `s->cluster_size*(cluster_num-s->current_mapping->begin)`, which will give us `0x2000 * (504-500)`, which is out of bound for this mapping and will produce some issues. Signed-off-by: Amjad Alsharafi <amjadsharafi10@gmail.com> --- block/vvfat.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)