In copy_to_sk, if an item is too large for the given buffer, it now returns
-EOVERFLOW instead of copying a search_header with len = 0. For backward
compatibility for the first item it still copies such a header to the buffer,
but not any other following items, which could have fitted.
tree_search changes -EOVERFLOW back to 0 to behave similiar to the way it
behaved before this patch.
Signed-off-by: Gerhard Heift <gerh...@heift.name>
---
fs/btrfs/ioctl.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 6aa79e0..04e1a98 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1887,8 +1887,20 @@ static noinline int copy_to_sk(struct btrfs_root *root,
if (!key_in_sk(key, sk))
continue;
- if (sizeof(sh) + item_len > buf_size)
+ if (sizeof(sh) + item_len > buf_size) {
+ if (*num_found) {
+ ret = 1;
+ goto overflow;
+ }
+
+ /*
+ * return one empty item back for v1, which does not
+ * handle -EOVERFLOW
+ */
+
item_len = 0;
+ ret = -EOVERFLOW;
+ }
if (sizeof(sh) + item_len + *sk_offset > buf_size) {
ret = 1;
@@ -1914,6 +1926,9 @@ static noinline int copy_to_sk(struct btrfs_root *root,
}
(*num_found)++;
+ if (ret) /* -EOVERFLOW from above */
+ goto overflow;
+
if (*num_found >= sk->nr_items)
break;
}
@@ -1990,7 +2005,8 @@ static noinline int search_ioctl(struct inode *inode,
break;
}
- ret = 0;
+ if (ret > 0)
+ ret = 0;
err:
sk->nr_items = num_found;
btrfs_free_path(path);
@@ -2013,6 +2029,14 @@ static noinline int btrfs_ioctl_tree_search(struct file
*file,
inode = file_inode(file);
ret = search_ioctl(inode, &args->key, sizeof(args->buf), args->buf);
+
+ /*
+ * In the origin implementation an overflow is handled by returning a
+ * search header with a len of zero, so reset ret.
+ */
+ if (ret == -EOVERFLOW)
+ ret = 0;
+
if (ret == 0 && copy_to_user(argp, args, sizeof(*args)))
ret = -EFAULT;
kfree(args);
--
1.8.5.3
--
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