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Subject[PATCH 0/4] net: caif: fix 2 memory leaks
Date
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.

NOTE: this series was tested by syzbot
https://syzkaller.appspot.com/bug?id=62bc71b5fa73349e2e6b6280eca9c9615ddeb585)

Pavel Skripkin (4):
net: caif: added cfserl_release function
net: caif: add proper error handling
net: caif: fix memory leak in caif_device_notify
net: caif: fix memory leak in cfusbl_device_notify

include/net/caif/caif_dev.h | 2 +-
include/net/caif/cfcnfg.h | 2 +-
include/net/caif/cfserl.h | 1 +
net/caif/caif_dev.c | 13 +++++++++----
net/caif/caif_usb.c | 14 +++++++++++++-
net/caif/cfcnfg.c | 16 +++++++++++-----
net/caif/cfserl.c | 5 +++++
7 files changed, 41 insertions(+), 12 deletions(-)

--
2.31.1

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