Instead of a heap allocation use a stack allocated sockaddr_storage to
support arbitrary length addr_len value (but bounds check it against the
maximum address length).
Signed-off-by: Kees Cook <kees@kernel.org>
---
net/core/rtnetlink.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index f0a520987085..eddd10b74f06 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2839,21 +2839,17 @@ static int do_setlink(const struct sk_buff *skb,
}
if (tb[IFLA_ADDRESS]) {
- struct sockaddr *sa;
- int len;
+ struct sockaddr_storage addr;
+ struct sockaddr *sa = (struct sockaddr *)&addr;
- len = sizeof(sa_family_t) + max_t(size_t, dev->addr_len,
- sizeof(*sa));
- sa = kmalloc(len, GFP_KERNEL);
- if (!sa) {
+ if (dev->addr_len > sizeof(addr.__data)) {
err = -ENOMEM;
goto errout;
}
sa->sa_family = dev->type;
- memcpy(sa->sa_data, nla_data(tb[IFLA_ADDRESS]),
+ memcpy(addr.__data, nla_data(tb[IFLA_ADDRESS]),
dev->addr_len);
err = dev_set_mac_address_user(dev, sa, extack);
- kfree(sa);
if (err)
goto errout;
status |= DO_SETLINK_MODIFIED;--
2.34.1