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 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html