From: Andy Grover Date: Fri, 4 Apr 2014 23:44:37 +0000 (-0700) Subject: target/tcm_fc: Fix use-after-free of ft_tpg X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=9e2dcd00681f852c1cb1864f79e9992ea1b5981f;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git target/tcm_fc: Fix use-after-free of ft_tpg commit 2c42be2dd4f6586728dba5c4e197afd5cfaded78 upstream. ft_del_tpg checks tpg->tport is set before unlinking the tpg from the tport when the tpg is being removed. Set this pointer in ft_tport_create, or the unlinking won't happen in ft_del_tpg and tport->tpg will reference a deleted object. This patch sets tpg->tport in ft_tport_create, because that's what ft_del_tpg checks, and is the only way to get back to the tport to clear tport->tpg. The bug was occuring when: - lport created, tport (our per-lport, per-provider context) is allocated. tport->tpg = NULL - tpg created - a PRLI is received. ft_tport_create is called, tpg is found and tport->tpg is set - tpg removed. ft_tpg is freed in ft_del_tpg. Since tpg->tport was not set, tport->tpg is not cleared and points at freed memory - Future calls to ft_tport_create return tport via first conditional, instead of searching for new tpg by calling ft_lport_find_tpg. tport->tpg is still invalid, and will access freed memory. see https://bugzilla.redhat.com/show_bug.cgi?id=1071340 Signed-off-by: Andy Grover Signed-off-by: Nicholas Bellinger Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/target/tcm_fc/tfc_sess.c b/drivers/target/tcm_fc/tfc_sess.c index 4859505ae2ed..639fdb395fb7 100644 --- a/drivers/target/tcm_fc/tfc_sess.c +++ b/drivers/target/tcm_fc/tfc_sess.c @@ -68,6 +68,7 @@ static struct ft_tport *ft_tport_create(struct fc_lport *lport) if (tport) { tport->tpg = tpg; + tpg->tport = tport; return tport; }