From: Mikulas Patocka mpatocka@redhat.com
commit 1cfd5d3399e87167b7f9157ef99daa0e959f395d upstream.
If the sector number is too high, dm_table_find_target() should return a pointer to a zeroed dm_target structure (the caller should test it with dm_target_is_valid).
However, for some table sizes, the code in dm_table_find_target() that performs btree lookup will access out of bound memory structures.
Fix this bug by testing the sector number at the beginning of dm_table_find_target(). Also, add an "inline" keyword to the function dm_table_get_size() because this is a hot path.
Fixes: 512875bd9661 ("dm: table detect io beyond device") Cc: stable@vger.kernel.org Reported-by: Zhang Tao kontais@zoho.com Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/dm-table.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1167,7 +1167,7 @@ void dm_table_event(struct dm_table *t) } EXPORT_SYMBOL(dm_table_event);
-sector_t dm_table_get_size(struct dm_table *t) +inline sector_t dm_table_get_size(struct dm_table *t) { return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0; } @@ -1192,6 +1192,9 @@ struct dm_target *dm_table_find_target(s unsigned int l, n = 0, k = 0; sector_t *node;
+ if (unlikely(sector >= dm_table_get_size(t))) + return &t->targets[t->num_targets]; + for (l = 0; l < t->depth; l++) { n = get_child(n, k); node = get_node(t, l, n);