fat: fix using uninitialized fields of fat_inode/fsinfo_inode (c0d0e351) · Commits · 戴 / test

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@mail.parknet.co.jp Signed-off-by:

OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Reported-by:

Moreno Bartalucci <moreno.bartalucci@tecnorama.it> Tested-by:

Moreno Bartalucci <moreno.bartalucci@tecnorama.it> Cc: <stable@vger.kernel.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

fs/fat/inode.c

+12 −1

Original line number	Diff line number	Diff line
		@@ -1359,6 +1359,16 @@ 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);
		@@ -1803,12 +1813,13 @@ int fat_fill_super(struct super_block sb, void data, int silent, int isvfat,
		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);

Admin message