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authorRitesh Harjani <riteshh@linux.ibm.com>2021-06-05 10:39:32 +0530
committerTheodore Ts'o <tytso@mit.edu>2021-10-01 00:03:51 -0400
commit75ca6ad408f459f00b09a64f04c774559848c097 (patch)
treefede0d63735d43b1a774ff76fc80597fe0a29e13 /fs/ext4
parent6fed83957f21eff11c8496e9f24253b03d2bc1dc (diff)
ext4: fix loff_t overflow in ext4_max_bitmap_size()
We should use unsigned long long rather than loff_t to avoid overflow in ext4_max_bitmap_size() for comparison before returning. w/o this patch sbi->s_bitmap_maxbytes was becoming a negative value due to overflow of upper_limit (with has_huge_files as true) Below is a quick test to trigger it on a 64KB pagesize system. sudo mkfs.ext4 -b 65536 -O ^has_extents,^64bit /dev/loop2 sudo mount /dev/loop2 /mnt sudo echo "hello" > /mnt/hello -> This will error out with "echo: write error: File too large" Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Link: https://lore.kernel.org/r/594f409e2c543e90fd836b78188dfa5c575065ba.1622867594.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/super.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index a52f1572daa5..9b5b2f63b470 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3030,17 +3030,17 @@ static loff_t ext4_max_size(int blkbits, int has_huge_files)
*/
static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
{
- loff_t res = EXT4_NDIR_BLOCKS;
+ unsigned long long upper_limit, res = EXT4_NDIR_BLOCKS;
int meta_blocks;
- loff_t upper_limit;
- /* This is calculated to be the largest file size for a dense, block
+
+ /*
+ * This is calculated to be the largest file size for a dense, block
* mapped file such that the file's total number of 512-byte sectors,
* including data and all indirect blocks, does not exceed (2^48 - 1).
*
* __u32 i_blocks_lo and _u16 i_blocks_high represent the total
* number of 512-byte sectors of the file.
*/
-
if (!has_huge_files) {
/*
* !has_huge_files or implies that the inode i_block field
@@ -3083,7 +3083,7 @@ static loff_t ext4_max_bitmap_size(int bits, int has_huge_files)
if (res > MAX_LFS_FILESIZE)
res = MAX_LFS_FILESIZE;
- return res;
+ return (loff_t)res;
}
static ext4_fsblk_t descriptor_loc(struct super_block *sb,