The order in which the ports are deleted from the list and freed and the
call to dsa_tree_remove_switch() is done is reversed, which leads to an
use after free condition. Reverse the two: first tear down the ports and
switch from the fabric, then free the ports associated with that switch
fabric.
Fixes: 05f294a85235 ("net: dsa: allocate ports on touch")
Signed-off-by: Florian Fainelli <[email protected]>
---
net/dsa/dsa2.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index ff2fa3950c62..9ef2caa13f27 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -874,12 +874,13 @@ static void dsa_switch_remove(struct dsa_switch *ds)
struct dsa_switch_tree *dst = ds->dst;
struct dsa_port *dp, *next;
+ dsa_tree_teardown(dst);
+
list_for_each_entry_safe(dp, next, &dst->ports, list) {
list_del(&dp->list);
kfree(dp);
}
- dsa_tree_teardown(dst);
dsa_tree_put(dst);
}
--
2.17.1
On Sat, 2 Nov 2019 20:13:26 -0700, Florian Fainelli <[email protected]> wrote:
> The order in which the ports are deleted from the list and freed and the
> call to dsa_tree_remove_switch() is done is reversed, which leads to an
s/dsa_tree_remove_switch/dsa_switch_remove/
> use after free condition. Reverse the two: first tear down the ports and
> switch from the fabric, then free the ports associated with that switch
> fabric.
>
> Fixes: 05f294a85235 ("net: dsa: allocate ports on touch")
> Signed-off-by: Florian Fainelli <[email protected]>
Thanks for reporting and fixing this!
Reviewed-by: Vivien Didelot <[email protected]>
From: Florian Fainelli <[email protected]>
Date: Sat, 2 Nov 2019 20:13:26 -0700
> The order in which the ports are deleted from the list and freed and the
> call to dsa_tree_remove_switch() is done is reversed, which leads to an
> use after free condition. Reverse the two: first tear down the ports and
> switch from the fabric, then free the ports associated with that switch
> fabric.
>
> Fixes: 05f294a85235 ("net: dsa: allocate ports on touch")
> Signed-off-by: Florian Fainelli <[email protected]>
Applied.