lkml.org 
[lkml]   [2021]   [Feb]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH][next][V2] fs/jfs: fix potential integer overflow on shift of a int
From
Date
On 2/11/21 7:01 AM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The left shift of int 32 bit integer constant 1 is evaluated using 32 bit
> arithmetic and then assigned to a signed 64 bit integer. In the case where
> l2nb is 32 or more this can lead to an overflow. Avoid this by shifting
> the value 1LL instead.
>
> Addresses-Coverity: ("Uninitentional integer overflow")
> Fixes: b40c2e665cd5 ("fs/jfs: TRIM support for JFS Filesystem")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Looks good. I'll include it in the next jfs drop.

Thanks,
Shaggy

> ---
>
> V2: shift 1LL rather than using BIT_ULL macro as suggested by
> Dave Kleikamp.
>
> ---
> fs/jfs/jfs_dmap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
> index 94b7c1cb5ceb..7aee15608619 100644
> --- a/fs/jfs/jfs_dmap.c
> +++ b/fs/jfs/jfs_dmap.c
> @@ -1656,7 +1656,7 @@ s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
> } else if (rc == -ENOSPC) {
> /* search for next smaller log2 block */
> l2nb = BLKSTOL2(nblocks) - 1;
> - nblocks = 1 << l2nb;
> + nblocks = 1LL << l2nb;
> } else {
> /* Trim any already allocated blocks */
> jfs_error(bmp->db_ipbmap->i_sb, "-EIO\n");
>

\
 
 \ /
  Last update: 2021-02-11 19:15    [W:1.265 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site