RE: [PATCH -next] bonding: Fix a use-after-free problem when bond_sysfs_slave_add() failed
From: huangguobin <hidden>
Date: 2021-11-02 02:55:31
Also in:
lkml
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 <redacted>; 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:
[...]
quoted hunk ↗ jump to hunk
Fixes: 7afcaec49696 (bonding: use kobject_put instead of _del after kobject_add) Signed-off-by: Huang Guobin <redacted> --- drivers/net/bonding/bond_sysfs_slave.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)diff --git a/drivers/net/bonding/bond_sysfs_slave.cb/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)