From: Amjad Alsharafi <amjadsharafi10@gmail.com>
To: qemu-devel@nongnu.org
Cc: Hanna Reitz <hreitz@redhat.com>, Kevin Wolf <kwolf@redhat.com>,
"open list:vvfat" <qemu-block@nongnu.org>,
Amjad Alsharafi <amjadsharafi10@gmail.com>
Subject: [PATCH v2 3/5] vvfat: Fix reading files with non-continuous clusters
Date: Sat, 4 May 2024 16:44:21 +0800 [thread overview]
Message-ID: <b96e79ca14e4d90a2b983d3c5d1bc98045979b68.1714811679.git.amjadsharafi10@gmail.com> (raw)
In-Reply-To: <cover.1714811679.git.amjadsharafi10@gmail.com>
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(-)
diff --git a/block/vvfat.c b/block/vvfat.c
index cb3ab81e29..87165abc26 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -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;
--
2.44.0
next prev parent reply other threads:[~2024-05-04 8:46 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-04 8:44 [PATCH v2 0/5] vvfat: Fix write bugs for large files and add iotests Amjad Alsharafi
2024-05-04 8:44 ` [PATCH v2 1/5] vvfat: Fix bug in writing to middle of file Amjad Alsharafi
2024-05-04 8:44 ` [PATCH v2 2/5] vvfat: Fix usage of `info.file.offset` Amjad Alsharafi
2024-05-04 8:44 ` Amjad Alsharafi [this message]
2024-05-04 8:44 ` [PATCH v2 4/5] iotests: Add `vvfat` tests Amjad Alsharafi
2024-05-04 8:44 ` [PATCH v2 5/5] iotests: Filter out `vvfat` fmt from failing tests Amjad Alsharafi
2024-05-04 8:51 ` [PATCH v2 0/5] vvfat: Fix write bugs for large files and add iotests Amjad Alsharafi
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