On Tue, Nov 05, 2024 at 11:59:49AM +0100, Eric Dumazet wrote:
On 11/4/24 11:25 PM, Kees Cook wrote:
quoted
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;
We already use too much stack space.
I'm finally coming back to this. I was over-thinking: this only calls
dev_set_mac_address_user() so it really is a true struct sockaddr.
Please move addr into struct rtnl_newlink_tbs ?
I couldn't figure out how that was meant to work -- I didn't see a
struct rtnl_newlink_tbs instance near this routine.
Regardless, I can just tweak the length and leave it heap allocated.
-Kees
--
Kees Cook