From 4c1e6b2ce13b154a4a69cee220c98976f4b784df Mon Sep 17 00:00:00 2001
From: Roel Kluin <roel.kluin@gmail.com>
Date: Fri, 18 Sep 2009 12:51:49 -0700
Subject: [PATCH] mtd: lart: Prevent a read from mtd->eraseregions[-1]

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
 drivers/mtd/devices/lart.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/devices/lart.c b/drivers/mtd/devices/lart.c
index 578de1c67bfe..f4359fe7150f 100644
--- a/drivers/mtd/devices/lart.c
+++ b/drivers/mtd/devices/lart.c
@@ -393,7 +393,8 @@ static int flash_erase (struct mtd_info *mtd,struct erase_info *instr)
 	* erase range is aligned with the erase size which is in
 	* effect here.
 	*/
-   if (instr->addr & (mtd->eraseregions[i].erasesize - 1)) return (-EINVAL);
+   if (i < 0 || (instr->addr & (mtd->eraseregions[i].erasesize - 1)))
+      return -EINVAL;
 
    /* Remember the erase region we start on */
    first = i;
@@ -409,7 +410,8 @@ static int flash_erase (struct mtd_info *mtd,struct erase_info *instr)
    i--;
 
    /* is the end aligned on a block boundary? */
-   if ((instr->addr + instr->len) & (mtd->eraseregions[i].erasesize - 1)) return (-EINVAL);
+   if (i < 0 || ((instr->addr + instr->len) & (mtd->eraseregions[i].erasesize - 1)))
+      return -EINVAL;
 
    addr = instr->addr;
    len = instr->len;
-- 
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