ext4: add explicit casts when masking cluster sizes

The missing casts can cause the high 64-bits of the physical blocks to
be lost.  Set up new macros which allows us to make sure the right
thing happen, even if at some point we end up supporting larger
logical block numbers.

Thanks to the Emese Revfy and the PaX security team for reporting this
issue.

Reported-by: PaX Team <pageexec@freemail.hu>
Reported-by: Emese Revfy <re.emese@gmail.com>                                 
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 04766d9a29cd..04a5c7504be9 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4126,7 +4126,7 @@ ext4_mb_initialize_context(struct ext4_allocation_context *ac,
         ext4_get_group_no_and_offset(sb, goal, &group, &block);
 
         /* set up allocation goals */
-        ac->ac_b_ex.fe_logical = ar->logical & ~(sbi->s_cluster_ratio - 1);
+        ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
         ac->ac_status = AC_STATUS_CONTINUE;
         ac->ac_sb = sb;
         ac->ac_inode = ar->inode;
@@ -4668,7 +4668,7 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
          * blocks at the beginning or the end unless we are explicitly
          * requested to avoid doing so.
          */
-        overflow = block & (sbi->s_cluster_ratio - 1);
+        overflow = EXT4_PBLK_COFF(sbi, block);
         if (overflow) {
                 if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
                         overflow = sbi->s_cluster_ratio - overflow;
@@ -4682,7 +4682,7 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
                         count += overflow;
                 }
         }
-        overflow = count & (sbi->s_cluster_ratio - 1);
+        overflow = EXT4_LBLK_COFF(sbi, count);
         if (overflow) {
                 if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
                         if (count > overflow)