Messages in this thread | | | Subject | Re: [PATCH][next][V2] fs/jfs: fix potential integer overflow on shift of a int | From | Dave Kleikamp <> | Date | Thu, 11 Feb 2021 11:49:59 -0600 |
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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"); >
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