This is a note to let you know that I've just added the patch titled
fat: fix using uninitialized fields of fat_inode/fsinfo_inode
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
fat-fix-using-uninitialized-fields-of-fat_inode-fsinfo_inode.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c0d0e351285161a515396b7b1ee53ec9ffd97e3c Mon Sep 17 00:00:00 2001
From: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
Date: Thu, 9 Mar 2017 16:17:37 -0800
Subject: fat: fix using uninitialized fields of fat_inode/fsinfo_inode
From: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
commit c0d0e351285161a515396b7b1ee53ec9ffd97e3c upstream.
Recently fallocate patch was merged and it uses
MSDOS_I(inode)->mmu_private at fat_evict_inode(). However,
fat_inode/fsinfo_inode that was introduced in past didn't initialize
MSDOS_I(inode) properly.
With those combinations, it became the cause of accessing random entry
in FAT area.
Link: http://lkml.kernel.org/r/87pohrj4i8.fsf@xxxxxxxxxxxxxxxxxx
Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
Reported-by: Moreno Bartalucci <moreno.bartalucci@xxxxxxxxxxxx>
Tested-by: Moreno Bartalucci <moreno.bartalucci@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/fat/inode.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1269,6 +1269,16 @@ out:
return 0;
}
+static void fat_dummy_inode_init(struct inode *inode)
+{
+ /* Initialize this dummy inode to work as no-op. */
+ MSDOS_I(inode)->mmu_private = 0;
+ MSDOS_I(inode)->i_start = 0;
+ MSDOS_I(inode)->i_logstart = 0;
+ MSDOS_I(inode)->i_attrs = 0;
+ MSDOS_I(inode)->i_pos = 0;
+}
+
static int fat_read_root(struct inode *inode)
{
struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
@@ -1713,12 +1723,13 @@ int fat_fill_super(struct super_block *s
fat_inode = new_inode(sb);
if (!fat_inode)
goto out_fail;
- MSDOS_I(fat_inode)->i_pos = 0;
+ fat_dummy_inode_init(fat_inode);
sbi->fat_inode = fat_inode;
fsinfo_inode = new_inode(sb);
if (!fsinfo_inode)
goto out_fail;
+ fat_dummy_inode_init(fsinfo_inode);
fsinfo_inode->i_ino = MSDOS_FSINFO_INO;
sbi->fsinfo_inode = fsinfo_inode;
insert_inode_hash(fsinfo_inode);
Patches currently in stable-queue which might be from hirofumi@xxxxxxxxxxxxxxxxxx are
queue-4.4/fat-fix-using-uninitialized-fields-of-fat_inode-fsinfo_inode.patch