Re: [PATCH v2] jfs: fix array-index-out-of-bounds in diAlloc

[Dave Kleikamp <dave.kleikamp@oracle.com>]

On 10/4/23 2:40AM, Manas Ghandat wrote:
> Currently there is not check against the agno of the iag while
> allocating new inodes to avoid fragmentation problem. Added the check
> which is required.

Applied to jfs-next

Thanks,
Shaggy

> 
> Reported-by: syzbot+79d792676d8ac050949f@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=79d792676d8ac050949f
> Signed-off-by: Manas Ghandat <ghandatmanas@gmail.com>
> ---
> V1 -> V2 : Added check for higher bound of agno
>   fs/jfs/jfs_imap.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
> index 799d3837e7c2..c0cf74e7392b 100644
> --- a/fs/jfs/jfs_imap.c
> +++ b/fs/jfs/jfs_imap.c
> @@ -1319,7 +1319,7 @@ diInitInode(struct inode *ip, int iagno, int ino, int extno, struct iag * iagp)
>   int diAlloc(struct inode *pip, bool dir, struct inode *ip)
>   {
>   	int rc, ino, iagno, addext, extno, bitno, sword;
> -	int nwords, rem, i, agno;
> +	int nwords, rem, i, agno, dn_numag;
>   	u32 mask, inosmap, extsmap;
>   	struct inode *ipimap;
>   	struct metapage *mp;
> @@ -1355,6 +1355,9 @@ int diAlloc(struct inode *pip, bool dir, struct inode *ip)
>   
>   	/* get the ag number of this iag */
>   	agno = BLKTOAG(JFS_IP(pip)->agstart, JFS_SBI(pip->i_sb));
> +	dn_numag = JFS_SBI(pip->i_sb)->bmap->db_numag;
> +	if (agno < 0 || agno > dn_numag)
> +		return -EIO;
>   
>   	if (atomic_read(&JFS_SBI(pip->i_sb)->bmap->db_active[agno])) {
>   		/*