Re: [PATCH 4.4 106/124] netlink: Do not subscribe to non-existent groups
From: Nathan Chancellor <hidden>
Date: 2018-08-04 18:07:47
Also in:
lkml, stable
On Sat, Aug 04, 2018 at 11:01:35AM +0200, Greg Kroah-Hartman wrote:
quoted hunk ↗ jump to hunk
4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Safonov <redacted> [ Upstream commit 7acf9d4237c46894e0fa0492dd96314a41742e84 ] Make ABI more strict about subscribing to group > ngroups. Code doesn't check for that and it looks bogus. (one can subscribe to non-existing group) Still, it's possible to bind() to all possible groups with (-1) Cc: "David S. Miller" <davem@davemloft.net> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Steffen Klassert <steffen.klassert@secunet.com> Cc: netdev@vger.kernel.org Signed-off-by: Dmitry Safonov <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/netlink/af_netlink.c | 1 + 1 file changed, 1 insertion(+)--- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c@@ -983,6 +983,7 @@ static int netlink_bind(struct socket *s if (err) return err; } + groups &= (1UL << nlk->ngroups) - 1; bound = nlk->bound; if (bound) {
Hi Greg,
I am so sorry I didn't catch this in my initial report but this commit
along with ba7aaf93ef2f ("netlink: Don't shift with UB on nlk->ngroups")
breaks mobile data on both the Pixel 2 XL and OnePlus 6. There is signal
but it just never connects to 3G/LTE. Reverting those two commits fixes
the issue.
Nothing stands out to me in dmesg unfortunately and iven neither device
is running a vanilla kernel, I cannot say if this is a problem in mainline
or not but I just wanted to make you aware of it.
Thanks!
Nathan