fuse: don't overflow LLONG_MAX with end offset (2f139829) · Commits · 戴 / test

Handle the special case of fuse_readpages() wanting to read the last page of a hugest file possible and overflowing the end offset in the process. This is basically to unbreak xfstests:generic/525 and prevent filesystems from doing bad things with an overflowing offset. Reported-by:

Xiao Yang <ice_yangxiao@163.com> Signed-off-by:

Miklos Szeredi <mszeredi@redhat.com>

fs/fuse/file.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -803,6 +803,10 @@ static int fuse_do_readpage(struct file file, struct page page)

		attr_ver = fuse_get_attr_version(fc);

		/* Don't overflow end offset */
		if (pos + (desc.length - 1) == LLONG_MAX)
		desc.length--;

		fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ);
		res = fuse_simple_request(fc, &ia.ap.args);
		if (res < 0)
		@@ -888,6 +892,14 @@ static void fuse_send_readpages(struct fuse_io_args ia, struct file file)
		ap->args.out_pages = true;
		ap->args.page_zeroing = true;
		ap->args.page_replace = true;

		/* Don't overflow end offset */
		if (pos + (count - 1) == LLONG_MAX) {
		count--;
		ap->descs[ap->num_pages - 1].length--;
		}
		WARN_ON((loff_t) (pos + count) < 0);

		fuse_read_args_fill(ia, file, pos, count, FUSE_READ);
		ia->read.attr_ver = fuse_get_attr_version(fc);
		if (fc->async_read) {

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