| Message ID | 20180314140322.233047-1-glider@google.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | netlink: make sure nladdr has correct size in netlink_connect() | expand |
On Wed, Mar 14, 2018 at 7:03 AM, Alexander Potapenko <glider@google.com> wrote: > KMSAN reports use of uninitialized memory in the case when |alen| is > smaller than sizeof(struct netlink_sock), and therefore |nladdr| isn't > fully copied from the userspace. > > Signed-off-by: Alexander Potapenko <glider@google.com> > Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2") > --- > net/netlink/af_netlink.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c > index 07e8478068f0..5d49b39e81c3 100644 > --- a/net/netlink/af_netlink.c > +++ b/net/netlink/af_netlink.c > @@ -1085,6 +1085,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, > if (addr->sa_family != AF_NETLINK) > return -EINVAL; > > + if (alen < sizeof(struct netlink_sock)) > + return -EINVAL; > + > Hmmm. How was this patch tested exactly ? Thanks.
On Wed, Mar 14, 2018 at 7:16 AM, Alexander Potapenko <glider@google.com> wrote: > > > > On Wed, Mar 14, 2018 at 3:11 PM Eric Dumazet <edumazet@google.com> wrote: >> >> On Wed, Mar 14, 2018 at 7:03 AM, Alexander Potapenko <glider@google.com> >> wrote: >> > KMSAN reports use of uninitialized memory in the case when |alen| is >> > smaller than sizeof(struct netlink_sock), and therefore |nladdr| isn't >> > fully copied from the userspace. >> > >> > Signed-off-by: Alexander Potapenko <glider@google.com> >> > Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2") >> > --- >> > net/netlink/af_netlink.c | 3 +++ >> > 1 file changed, 3 insertions(+) >> > >> > diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c >> > index 07e8478068f0..5d49b39e81c3 100644 >> > --- a/net/netlink/af_netlink.c >> > +++ b/net/netlink/af_netlink.c >> > @@ -1085,6 +1085,9 @@ static int netlink_connect(struct socket *sock, >> > struct sockaddr *addr, >> > if (addr->sa_family != AF_NETLINK) >> > return -EINVAL; >> > >> > + if (alen < sizeof(struct netlink_sock)) >> > + return -EINVAL; >> > + >> > >> >> Hmmm. How was this patch tested exactly ? > > You're absolutely right, I should have been using sizeof(sockaddr_nl). > The reproducer that I used to trigger the bug was passing alen=2, so the > patch still worked despite being incorrect. > Is there any generic set of networking tests that I can use for such bugs? There are upstream tests in tools/testing/selftests/ In your case, making sure tools like iproute2 ss are still working would have done the job.
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 07e8478068f0..5d49b39e81c3 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1085,6 +1085,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr, if (addr->sa_family != AF_NETLINK) return -EINVAL; + if (alen < sizeof(struct netlink_sock)) + return -EINVAL; + if ((nladdr->nl_groups || nladdr->nl_pid) && !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND)) return -EPERM;
KMSAN reports use of uninitialized memory in the case when |alen| is smaller than sizeof(struct netlink_sock), and therefore |nladdr| isn't fully copied from the userspace. Signed-off-by: Alexander Potapenko <glider@google.com> Fixes: 1da177e4c3f41524 ("Linux-2.6.12-rc2") --- net/netlink/af_netlink.c | 3 +++ 1 file changed, 3 insertions(+)