From: David S. Miller <davem@davemloft.net>
Date: Thu, 3 Jun 2021 22:05:07 +0000 (-0700)
Subject: Merge branch 'caif-fixes'
X-Git-Tag: v5.13-rc5~9^2~13
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e03101824d256c73f21d0672b75175c01cc64fac;p=thirdparty%2Fkernel%2Flinux.git

Merge branch 'caif-fixes'

Pavel Skripkin says:

====================
This patch series fix 2 memory leaks in caif
interface.

Syzbot reported memory leak in cfserl_create().
The problem was in cfcnfg_add_phy_layer() function.
This function accepts struct cflayer *link_support and
assign it to corresponting structures, but it can fail
in some cases.

These cases must be handled to prevent leaking allocated
struct cflayer *link_support pointer, because if error accured
before assigning link_support pointer to somewhere, this pointer
must be freed.

Fail log:

[   49.051872][ T7010] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   49.110236][ T7042] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   49.134936][ T7045] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   49.163083][ T7043] caif:cfcnfg_add_phy_layer(): Too many CAIF Link Layers (max 6)
[   55.248950][ T6994] kmemleak: 4 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

int cfcnfg_add_phy_layer(..., struct cflayer *link_support, ...)
{
...
	/* CAIF protocol allow maximum 6 link-layers */
	for (i = 0; i < 7; i++) {
		phyid = (dev->ifindex + i) & 0x7;
		if (phyid == 0)
			continue;
		if (cfcnfg_get_phyinfo_rcu(cnfg, phyid) == NULL)
			goto got_phyid;
	}
	pr_warn("Too many CAIF Link Layers (max 6)\n");
	goto out;
...
	if (link_support != NULL) {
		link_support->id = phyid;
		layer_set_dn(frml, link_support);
		layer_set_up(link_support, frml);
		layer_set_dn(link_support, phy_layer);
		layer_set_up(phy_layer, link_support);
	}
...
}

As you can see, if cfcnfg_add_phy_layer fails before layer_set_*,
link_support becomes leaked.

So, in this series, I made cfcnfg_add_phy_layer()
return an int and added error handling code to prevent
leaking link_support pointer in caif_device_notify()
and cfusbl_device_notify() functions.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
---

e03101824d256c73f21d0672b75175c01cc64fac