mtd: mtdconcat: prevent a read from eraseregions[-1]

If the erase region was found in the first iteration we read from
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>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index 792b547786b8..db6de74082ad 100644
--- a/drivers/mtd/mtdconcat.c
+++ b/drivers/mtd/mtdconcat.c
@@ -427,7 +427,7 @@ static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
                  * to-be-erased area begins. Verify that the starting
                  * offset is aligned to this region's erase size:
                  */
-                if (instr->addr & (erase_regions[i].erasesize - 1))
+                if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
                         return -EINVAL;
 
                 /*
@@ -440,8 +440,8 @@ static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
                 /*
                  * check if the ending offset is aligned to this region's erase size
                  */
-                if ((instr->addr + instr->len) & (erase_regions[i].erasesize -
-                                                  1))
+                if (i < 0 || ((instr->addr + instr->len) &
+                                        (erase_regions[i].erasesize - 1)))
                         return -EINVAL;
         }