2018-07-13 06:48:01

by OGAWA Hirofumi

[permalink] [raw]
Subject: [PATCH] fat: Fix potential shift wrap with FITRIM ioctl on FAT

This patch is the fix of fat-add-fitrim-ioctl-for-fat-file-system.patch.
Maybe better to merge with it (if it is easy).

Anyway, please apply this with above patch.

--------
From: Wentao Wang <[email protected]>

If we keep "trimmed" as an u32, there will be a potential shift wrap.

It would be a problem on a larger than 4GB partition with
FAT32. Though most tools who call this ioctl would ignore this value,
it would be great to fix it.

Signed-off-by: Wentao Wang <[email protected]>
Signed-off-by: OGAWA Hirofumi <[email protected]>
---

fs/fat/fatent.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff -puN fs/fat/fatent.c~fat-fitrim-fix fs/fat/fatent.c
--- linux/fs/fat/fatent.c~fat-fitrim-fix 2018-07-13 15:39:14.417110998 +0900
+++ linux-hirofumi/fs/fat/fatent.c 2018-07-13 15:39:14.418110996 +0900
@@ -705,8 +705,8 @@ int fat_trim_fs(struct inode *inode, str
struct msdos_sb_info *sbi = MSDOS_SB(sb);
const struct fatent_operations *ops = sbi->fatent_ops;
struct fat_entry fatent;
- u64 ent_start, ent_end, minlen;
- u32 free = 0, trimmed = 0;
+ u64 ent_start, ent_end, minlen, trimmed = 0;
+ u32 free = 0;
unsigned long reada_blocks, reada_mask, cur_block = 0;
int err = 0;

_

--
OGAWA Hirofumi <[email protected]>