diff options
| author | Kees Cook <kees@kernel.org> | 2025-05-21 23:46:15 +0300 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-05-27 09:25:43 +0300 |
| commit | 6b12e0a3c3c9565c7dc106e2a8b1d433b1aa8eb6 (patch) | |
| tree | e1b2ebd412bdfe544f8dd192b011f7bc9e0801b3 /net/core | |
| parent | 9ca6804ab7c34f65fcf2e29333a39e7807c30b60 (diff) | |
| download | linux-6b12e0a3c3c9565c7dc106e2a8b1d433b1aa8eb6.tar.xz | |
rtnetlink: do_setlink: Use struct sockaddr_storage
Instead of a heap allocating a variably sized struct sockaddr and lying
about the type in the call to netif_set_mac_address(), use a stack
allocated struct sockaddr_storage. This lets us drop the cast and avoid
the allocation.
Putting "ss" on the stack means it will get a reused stack slot since
it is the same size (128B) as other existing single-scope stack variables,
like the vfinfo array (128B), so no additional stack space is used by
this function.
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Kees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20250521204619.2301870-7-kees@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/rtnetlink.c | 19 |
1 files changed, 4 insertions, 15 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 9743f1c2ae3c..f9a35bdc58ad 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3080,17 +3080,7 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, } if (tb[IFLA_ADDRESS]) { - struct sockaddr *sa; - int len; - - len = sizeof(sa_family_t) + max_t(size_t, dev->addr_len, - sizeof(*sa)); - sa = kmalloc(len, GFP_KERNEL); - if (!sa) { - err = -ENOMEM; - goto errout; - } - sa->sa_family = dev->type; + struct sockaddr_storage ss = { }; netdev_unlock_ops(dev); @@ -3098,10 +3088,9 @@ static int do_setlink(const struct sk_buff *skb, struct net_device *dev, down_write(&dev_addr_sem); netdev_lock_ops(dev); - memcpy(sa->sa_data, nla_data(tb[IFLA_ADDRESS]), - dev->addr_len); - err = netif_set_mac_address(dev, (struct sockaddr_storage *)sa, extack); - kfree(sa); + ss.ss_family = dev->type; + memcpy(ss.__data, nla_data(tb[IFLA_ADDRESS]), dev->addr_len); + err = netif_set_mac_address(dev, &ss, extack); if (err) { up_write(&dev_addr_sem); goto errout; |