This is a note to let you know that I've just added the patch titled
net: macsec: fix double free of percpu stats
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-macsec-fix-double-free-of-percpu-stats.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9ae6ab7fb80b3ceeb5746656a45e907e65773009
Author: Fedor Pchelkin <pchelkin@xxxxxxxxx>
Date: Tue Jun 13 22:22:20 2023 +0300
net: macsec: fix double free of percpu stats
[ Upstream commit 0c0cf3db83f8c7c9bb141c2771a34043bcf952ef ]
Inside macsec_add_dev() we free percpu macsec->secy.tx_sc.stats and
macsec->stats on some of the memory allocation failure paths. However, the
net_device is already registered to that moment: in macsec_newlink(), just
before calling macsec_add_dev(). This means that during unregister process
its priv_destructor - macsec_free_netdev() - will be called and will free
the stats again.
Remove freeing percpu stats inside macsec_add_dev() because
macsec_free_netdev() will correctly free the already allocated ones. The
pointers to unallocated stats stay NULL, and free_percpu() treats that
correctly.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 0a28bfd4971f ("net/macsec: Add MACsec skb_metadata_dst Tx Data path support")
Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver")
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
Reviewed-by: Sabrina Dubroca <sd@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 25616247d7a56..e040c191659b9 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -3987,17 +3987,15 @@ static int macsec_add_dev(struct net_device *dev, sci_t sci, u8 icv_len)
return -ENOMEM;
secy->tx_sc.stats = netdev_alloc_pcpu_stats(struct pcpu_tx_sc_stats);
- if (!secy->tx_sc.stats) {
- free_percpu(macsec->stats);
+ if (!secy->tx_sc.stats)
return -ENOMEM;
- }
secy->tx_sc.md_dst = metadata_dst_alloc(0, METADATA_MACSEC, GFP_KERNEL);
- if (!secy->tx_sc.md_dst) {
- free_percpu(secy->tx_sc.stats);
- free_percpu(macsec->stats);
+ if (!secy->tx_sc.md_dst)
+ /* macsec and secy percpu stats will be freed when unregistering
+ * net_device in macsec_free_netdev()
+ */
return -ENOMEM;
- }
if (sci == MACSEC_UNDEF_SCI)
sci = dev_to_sci(dev, MACSEC_PORT_ES);
