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authorAndries E. Brouwer <Andries.Brouwer@cwi.nl>2007-12-17 16:19:55 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-12-17 19:28:16 -0800
commitb47b6f38e5202c924bfe7632dce5dda4e3d40731 (patch)
treeb9dfeb426adc7125ac7828d5b646d893163314c6
parent9e2de407bec98fb07040f658f55fb71ba1b594f5 (diff)
ext3, ext4: avoid divide by zero
As it turns out, the kernel divides by EXT3_INODES_PER_GROUP(s) when mounting an ext3 filesystem. If that number is zero, a crash follows. Below a patch. This crash was reported by Joeri de Ruiter, Carst Tankink and Pim Vullers. Cc: <linux-ext4@vger.kernel.org> Acked-by: Alan Cox <alan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/ext3/super.c2
-rw-r--r--fs/ext4/super.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index de55da9e28b..cb14de1502c 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1676,7 +1676,7 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
- if (EXT3_INODE_SIZE(sb) == 0)
+ if (EXT3_INODE_SIZE(sb) == 0 || EXT3_INODES_PER_GROUP(sb) == 0)
goto cantfind_ext3;
sbi->s_inodes_per_block = blocksize / EXT3_INODE_SIZE(sb);
if (sbi->s_inodes_per_block == 0)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 8031dc0e24e..1ca0f546c46 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1797,7 +1797,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
sbi->s_desc_size = EXT4_MIN_DESC_SIZE;
sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
- if (EXT4_INODE_SIZE(sb) == 0)
+ if (EXT4_INODE_SIZE(sb) == 0 || EXT4_INODES_PER_GROUP(sb) == 0)
goto cantfind_ext4;
sbi->s_inodes_per_block = blocksize / EXT4_INODE_SIZE(sb);
if (sbi->s_inodes_per_block == 0)