diff options
| author | Antoine Tenart <atenart@kernel.org> | 2021-03-18 21:37:51 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-03-19 00:56:22 +0300 |
| commit | 2d05bf015308275f7c67a780f70026077285cfc0 (patch) | |
| tree | b73d016a2d2f6a8432ac2f6f04c0d971408723ac /net/core | |
| parent | 2db6cdaebac83c13acb165594b09282fa03cec89 (diff) | |
| download | linux-2d05bf015308275f7c67a780f70026077285cfc0.tar.xz | |
net: fix use after free in xps
When setting up an new dev_maps in __netif_set_xps_queue, we remove and
free maps from unused CPUs/rx-queues near the end of the function; by
calling remove_xps_queue. However it's possible those maps are also part
of the old not-freed-yet dev_maps, which might be used concurrently.
When that happens, a map can be freed while its corresponding entry in
the old dev_maps table isn't NULLed, leading to: "BUG: KASAN:
use-after-free" in different places.
This fixes the map freeing logic for unused CPUs/rx-queues, to also NULL
the map entries from the old dev_maps table.
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index c8ce2dfcc97d..d5f6ba209f1e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2460,7 +2460,7 @@ static DEFINE_MUTEX(xps_map_mutex); rcu_dereference_protected((P), lockdep_is_held(&xps_map_mutex)) static bool remove_xps_queue(struct xps_dev_maps *dev_maps, - int tci, u16 index) + struct xps_dev_maps *old_maps, int tci, u16 index) { struct xps_map *map = NULL; int pos; @@ -2479,6 +2479,8 @@ static bool remove_xps_queue(struct xps_dev_maps *dev_maps, break; } + if (old_maps) + RCU_INIT_POINTER(old_maps->attr_map[tci], NULL); RCU_INIT_POINTER(dev_maps->attr_map[tci], NULL); kfree_rcu(map, rcu); return false; @@ -2499,7 +2501,7 @@ static bool remove_xps_queue_cpu(struct net_device *dev, int i, j; for (i = count, j = offset; i--; j++) { - if (!remove_xps_queue(dev_maps, tci, j)) + if (!remove_xps_queue(dev_maps, NULL, tci, j)) break; } @@ -2631,7 +2633,7 @@ static void xps_copy_dev_maps(struct xps_dev_maps *dev_maps, int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask, u16 index, enum xps_map_type type) { - struct xps_dev_maps *dev_maps, *new_dev_maps = NULL; + struct xps_dev_maps *dev_maps, *new_dev_maps = NULL, *old_dev_maps = NULL; const unsigned long *online_mask = NULL; bool active = false, copy = false; int i, j, tci, numa_node_id = -2; @@ -2766,7 +2768,7 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask, } } - kfree_rcu(dev_maps, rcu); + old_dev_maps = dev_maps; out_no_old_maps: dev_maps = new_dev_maps; @@ -2792,10 +2794,15 @@ out_no_new_maps: netif_attr_test_online(j, online_mask, dev_maps->nr_ids)) continue; - active |= remove_xps_queue(dev_maps, tci, index); + active |= remove_xps_queue(dev_maps, + copy ? old_dev_maps : NULL, + tci, index); } } + if (old_dev_maps) + kfree_rcu(old_dev_maps, rcu); + /* free map if not active */ if (!active) reset_xps_maps(dev, dev_maps, type); |