From 4f2f76f751433908364ccff82f437a57d0e6e9b7 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Fri, 25 May 2018 12:51:25 -0400 Subject: [PATCH] ext4: fix fencepost error in check for inode count overflow during resize ext4_resize_fs() has an off-by-one bug when checking whether growing of a filesystem will not overflow inode count. As a result it allows a filesystem with 8192 inodes per group to grow to 64TB which overflows inode count to 0 and makes filesystem unusable. Fix it. Cc: stable@vger.kernel.org Fixes: 3f8a6411fbada1fa482276591e037f3b1adcf55b Reported-by: Jaco Kroon Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Reviewed-by: Andreas Dilger --- fs/ext4/resize.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index b6bec27..d792b76 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1933,7 +1933,7 @@ retry: return 0; n_group = ext4_get_group_number(sb, n_blocks_count - 1); - if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) { + if (n_group >= (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) { ext4_warning(sb, "resize would cause inodes_count overflow"); return -EINVAL; } -- 2.7.4