On Thu 30-04-20 10:25:18, Ritesh Harjani wrote: > We better warn the fibmap user and not return a truncated and therefore > an incorrect block map address if the bmap() returned block address > is greater than INT_MAX (since user supplied integer pointer). > > It's better to pr_warn() all user of ioctl_fibmap() and return a proper > error code rather than silently letting a FS corruption happen if the > user tries to fiddle around with the returned block map address. > > We fix this by returning an error code of -ERANGE and returning 0 as the > block mapping address in case if it is > INT_MAX. > > Now iomap_bmap() could be called from either of these two paths. > Either when a user is calling an ioctl_fibmap() interface to get > the block mapping address or by some filesystem via use of bmap() > internal kernel API. > bmap() kernel API is well equipped with handling of u64 addresses. > > WARN condition in iomap_bmap_actor() was mainly added to warn all > the fibmap users. But now that we have directly added this warning > for all fibmap users and also made sure to return 0 as block map address > in case if addr > INT_MAX. > So we can now remove this logic from iomap_bmap_actor(). > > Signed-off-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx> Looks good to me. You can add: Reviewed-by: Jan Kara <jack@xxxxxxx> Honza > --- > v2 -> v3: > 1. Added file path info using (%pD4) > 2. Dropped Reviewed-by tags for reviewing this final version. > > fs/ioctl.c | 8 ++++++++ > fs/iomap/fiemap.c | 5 +---- > 2 files changed, 9 insertions(+), 4 deletions(-) > > diff --git a/fs/ioctl.c b/fs/ioctl.c > index f1d93263186c..6b8629fbe0fd 100644 > --- a/fs/ioctl.c > +++ b/fs/ioctl.c > @@ -55,6 +55,7 @@ EXPORT_SYMBOL(vfs_ioctl); > static int ioctl_fibmap(struct file *filp, int __user *p) > { > struct inode *inode = file_inode(filp); > + struct super_block *sb = inode->i_sb; > int error, ur_block; > sector_t block; > > @@ -71,6 +72,13 @@ static int ioctl_fibmap(struct file *filp, int __user *p) > block = ur_block; > error = bmap(inode, &block); > > + if (block > INT_MAX) { > + error = -ERANGE; > + pr_warn_ratelimited("[%s/%d] FS: %s File: %pD4 would truncate fibmap result\n", > + current->comm, task_pid_nr(current), > + sb->s_id, filp); > + } > + > if (error) > ur_block = 0; > else > diff --git a/fs/iomap/fiemap.c b/fs/iomap/fiemap.c > index bccf305ea9ce..d55e8f491a5e 100644 > --- a/fs/iomap/fiemap.c > +++ b/fs/iomap/fiemap.c > @@ -117,10 +117,7 @@ iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length, > > if (iomap->type == IOMAP_MAPPED) { > addr = (pos - iomap->offset + iomap->addr) >> inode->i_blkbits; > - if (addr > INT_MAX) > - WARN(1, "would truncate bmap result\n"); > - else > - *bno = addr; > + *bno = addr; > } > return 0; > } > -- > 2.21.0 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR