On Mon 30-03-20 15:27:12, Lukas Czerner wrote: > On Mon, Mar 30, 2020 at 11:09:32AM +0200, Jan Kara wrote: > > There is an off-by-one error in dx_grow_tree() when checking whether we > > can add another level to the tree. Thus we can grow tree too much > > leading to possible crashes in the library or corrupted filesystem. Fix > > the bug. > > Looks good, thanks > > Reviewed-by: Lukas Czerner <lczerner@xxxxxxxxxx> > > Don't we have basically the same off-by-one in > e2fsck/pass1.c handle_htree() ? > > if ((root->indirect_levels > ext2_dir_htree_level(fs)) && > fix_problem(ctx, PR_1_HTREE_DEPTH, pctx)) I don't think so. It is indeed correct for root->indirect_levels to be equal to ext2_dir_htree_level(). However dx_grow_tree() is going to increase root->indirect_levels by 1 which is where tree would become invalid... Honza > > > > Signed-off-by: Jan Kara <jack@xxxxxxx> > > --- > > lib/ext2fs/link.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/lib/ext2fs/link.c b/lib/ext2fs/link.c > > index 7b5bb022117c..469eea8cd06d 100644 > > --- a/lib/ext2fs/link.c > > +++ b/lib/ext2fs/link.c > > @@ -473,7 +473,7 @@ static errcode_t dx_grow_tree(ext2_filsys fs, ext2_ino_t dir, > > ext2fs_le16_to_cpu(info->frames[i].head->limit)) > > break; > > /* Need to grow tree depth? */ > > - if (i < 0 && info->levels > ext2_dir_htree_level(fs)) > > + if (i < 0 && info->levels >= ext2_dir_htree_level(fs)) > > return EXT2_ET_DIR_NO_SPACE; > > lblk = size / fs->blocksize; > > size += fs->blocksize; > > -- > > 2.16.4 > > > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
