Messages in this thread Patch in this message | | | From | huangguobin <> | Subject | RE: [PATCH -next] bonding: Fix a use-after-free problem when bond_sysfs_slave_add() failed | Date | Tue, 2 Nov 2021 02:55:16 +0000 |
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I think bond_sysfs_slave_del should not be used in the error handling process, because bond_sysfs_slave_del will traverse all slave_attrs and release them. When sysfs_create_file fails, only some attributes may be created successfully. -----Original Message----- From: Julian Wiedmann [mailto:jwi@linux.ibm.com] Sent: Tuesday, November 2, 2021 3:31 AM To: huangguobin <huangguobin4@huawei.com>; j.vosburgh@gmail.com; vfalico@gmail.com; andy@greyhouse.net; davem@davemloft.net; kuba@kernel.org Cc: netdev@vger.kernel.org; linux-kernel@vger.kernel.org Subject: Re: [PATCH -next] bonding: Fix a use-after-free problem when bond_sysfs_slave_add() failed
On 01.11.21 15:34, Huang Guobin wrote: > When I do fuzz test for bonding device interface, I got the following > use-after-free Calltrace: >
[...]
> Fixes: 7afcaec49696 (bonding: use kobject_put instead of _del after > kobject_add) > Signed-off-by: Huang Guobin <huangguobin4@huawei.com> > --- > drivers/net/bonding/bond_sysfs_slave.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/net/bonding/bond_sysfs_slave.c > b/drivers/net/bonding/bond_sysfs_slave.c > index fd07561..d1a5b3f 100644 > --- a/drivers/net/bonding/bond_sysfs_slave.c > +++ b/drivers/net/bonding/bond_sysfs_slave.c > @@ -137,18 +137,23 @@ static ssize_t slave_show(struct kobject *kobj, > > int bond_sysfs_slave_add(struct slave *slave) { > - const struct slave_attribute **a; > + const struct slave_attribute **a, **b; > int err; > > for (a = slave_attrs; *a; ++a) { > err = sysfs_create_file(&slave->kobj, &((*a)->attr)); > if (err) { > - kobject_put(&slave->kobj); > - return err; > + goto err_remove_file; > } > } > > return 0; > + > +err_remove_file: > + for (b = slave_attrs; b < a; ++b) > + sysfs_remove_file(&slave->kobj, &((*b)->attr)); > + > + return err; > } >
This looks like a candidate for sysfs_create_files(), no?
> void bond_sysfs_slave_del(struct slave *slave) >
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