From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Fri, 21 Mar 2014 01:56:56 +0000 (+0100)
Subject: PV-GRUB: fix blk access at end of disk
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~5360
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks://%22Dat/%22http:/www.example.com/cgi/%22https:/%22bookmarks:/%22Dat?a=commitdiff_plain;h=51e18e41e39a682de5a2e60ad86048dc6344efec;p=xen.git

PV-GRUB: fix blk access at end of disk

GRUB usually always loads a whole disk track, even if that means going
beyond the end of the disk.  We thus have to gracefully return an error,
instead of letting the blkfront go panic.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---

diff --git a/stubdom/grub/mini-os.c b/stubdom/grub/mini-os.c
index 8cecf9013f..64ab962fee 100644
--- a/stubdom/grub/mini-os.c
+++ b/stubdom/grub/mini-os.c
@@ -126,6 +126,9 @@ biosdisk (int read, int drive, struct geometry *geometry,
     if (i >= blk_nb)
         return -1;
 
+    if (sector + nsec > geometry->total_sectors)
+      return -1;
+
     aiocb.aio_dev = blk_dev[i];
     aiocb.aio_buf = addr;
     aiocb.aio_nbytes = (size_t)nsec * blk_info[i].sector_size;