6.16-stable review patch. If anyone has any objections, please let me know.
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From: Alok Tiwari alok.a.tiwari@oracle.com
[ Upstream commit 1dbfb0363224f6da56f6655d596dc5097308d6f5 ]
Per family bind/unbind callbacks were introduced to allow families to track multicast group consumer presence, e.g. to start or stop producing events depending on listeners.
However, in genl_bind() the bind() callback was invoked even if capability checks failed and ret was set to -EPERM. This means that callbacks could run on behalf of unauthorized callers while the syscall still returned failure to user space.
Fix this by only invoking bind() after "if (ret) break;" check i.e. after permission checks have succeeded.
Fixes: 3de21a8990d3 ("genetlink: Add per family bind/unbind callbacks") Signed-off-by: Alok Tiwari alok.a.tiwari@oracle.com Link: https://patch.msgid.link/20250905135731.3026965-1-alok.a.tiwari@oracle.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netlink/genetlink.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index 104732d345434..978c129c60950 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1836,6 +1836,9 @@ static int genl_bind(struct net *net, int group) !ns_capable(net->user_ns, CAP_SYS_ADMIN)) ret = -EPERM;
+ if (ret) + break; + if (family->bind) family->bind(i);