[PATCH AUTOSEL 5.9 14/55] gfs2: Free rd_bits later in gfs2_clear_rgrpd to fix use-after-free

Sasha Levin
2020-11-10T04:07:50Z

From: Bob Peterson <rpeterso@redhat.com>

[ Upstream commit d0f17d3883f1e3f085d38572c2ea8edbd5150172 ]

Function gfs2_clear_rgrpd calls kfree(rgd->rd_bits) before calling
return_all_reservations, but return_all_reservations still dereferences
rgd->rd_bits in __rs_deltree. Fix that by moving the call to kfree below the
call to return_all_reservations.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/gfs2/rgrp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 1bba5a9d45fa3..1d65db1b3914a 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -719,9 +719,9 @@ void gfs2_clear_rgrpd(struct gfs2_sbd *sdp)
}

gfs2_free_clones(rgd);
+ return_all_reservations(rgd);
kfree(rgd->rd_bits);
rgd->rd_bits = NULL;
- return_all_reservations(rgd);
kmem_cache_free(gfs2_rgrpd_cachep, rgd);
}
}
--
2.27.0