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Commit 4b905671 authored by Jan Kara's avatar Jan Kara Committed by Theodore Ts'o
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jbd2: Fix oops in jbd2_journal_init_inode() on corrupted fs 

On 32-bit system with CONFIG_LBD getblk can fail because provided
block number is too big.  Add error checks so we fail gracefully if
getblk() returns NULL (which can also happen on memory allocation
failures).

Thanks to David Maciejak from Fortinet's FortiGuard Global Security
Research Team for reporting this bug.

http://bugzilla.kernel.org/show_bug.cgi?id=12370



Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
cc: stable@kernel.org
parent 83982b6f

fs/jbd2/journal.c

+27 −13
Original line number Diff line number Diff line
@@ -632,6 +632,8 @@ struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal) 
		return NULL;



	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);

	if (!bh)

		return NULL;

	lock_buffer(bh);

	memset(bh->b_data, 0, journal->j_blocksize);

	set_buffer_uptodate(bh);
@@ -1021,15 +1023,14 @@ journal_t * jbd2_journal_init_dev(struct block_device *bdev, 


	/* journal descriptor can store up to n blocks -bzzz */

	journal->j_blocksize = blocksize;

	jbd2_stats_proc_init(journal);

	n = journal->j_blocksize / sizeof(journal_block_tag_t);

	journal->j_wbufsize = n;

	journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);

	if (!journal->j_wbuf) {

		printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",

			__func__);

		kfree(journal);

		journal = NULL;

		goto out;

		goto out_err;

	}

	journal->j_dev = bdev;

	journal->j_fs_dev = fs_dev;
@@ -1039,14 +1040,22 @@ journal_t * jbd2_journal_init_dev(struct block_device *bdev, 
	p = journal->j_devname;

	while ((p = strchr(p, '/')))

		*p = '!';

	jbd2_stats_proc_init(journal);



	bh = __getblk(journal->j_dev, start, journal->j_blocksize);

	J_ASSERT(bh != NULL);

	if (!bh) {

		printk(KERN_ERR

		       "%s: Cannot get buffer for journal superblock\n",

		       __func__);

		goto out_err;

	}

	journal->j_sb_buffer = bh;

	journal->j_superblock = (journal_superblock_t *)bh->b_data;

out:



	return journal;

out_err:

	jbd2_stats_proc_exit(journal);

	kfree(journal);

	return NULL;

}



/**
@@ -1094,9 +1103,7 @@ journal_t * jbd2_journal_init_inode (struct inode *inode) 
	if (!journal->j_wbuf) {

		printk(KERN_ERR "%s: Cant allocate bhs for commit thread\n",

			__func__);

		jbd2_stats_proc_exit(journal);

		kfree(journal);

		return NULL;

		goto out_err;

	}



	err = jbd2_journal_bmap(journal, 0, &blocknr);
@@ -1104,17 +1111,24 @@ journal_t * jbd2_journal_init_inode (struct inode *inode) 
	if (err) {

		printk(KERN_ERR "%s: Cannnot locate journal superblock\n",

		       __func__);

		jbd2_stats_proc_exit(journal);

		kfree(journal);

		return NULL;

		goto out_err;

	}



	bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);

	J_ASSERT(bh != NULL);

	if (!bh) {

		printk(KERN_ERR

		       "%s: Cannot get buffer for journal superblock\n",

		       __func__);

		goto out_err;

	}

	journal->j_sb_buffer = bh;

	journal->j_superblock = (journal_superblock_t *)bh->b_data;



	return journal;

out_err:

	jbd2_stats_proc_exit(journal);

	kfree(journal);

	return NULL;

}



/*