From b66e364f131228f4215ff8f0b8173f14931d9b6c Mon Sep 17 00:00:00 2001 From: Michael Chang Date: Tue, 24 Apr 2018 14:13:04 +0800 Subject: [PATCH] bufio: Round up block size to power of 2 Rounding up the bufio->block_size to meet power of 2 to facilitate next_buf calculation in grub_bufio_read(). Signed-off-by: Michael Chang Reviewed-by: Daniel Kiper --- grub-core/io/bufio.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/grub-core/io/bufio.c b/grub-core/io/bufio.c index 22438277d74..dbed6474431 100644 --- a/grub-core/io/bufio.c +++ b/grub-core/io/bufio.c @@ -61,6 +61,13 @@ grub_bufio_open (grub_file_t io, int size) size = ((io->size > GRUB_BUFIO_MAX_SIZE) ? GRUB_BUFIO_MAX_SIZE : io->size); + /* + * Round up size to power of 2 which the binary math to + * calculate next_buf in grub_bufio_read() requires. + */ + while (size & (size - 1)) + size = (size | (size - 1)) + 1; + bufio = grub_zalloc (sizeof (struct grub_bufio) + size); if (! bufio) {