From: Alexandra Winter Date: Mon, 10 Aug 2026 11:14:32 +0000 (+0200) Subject: net/dibs: Correct freeing of dmb_clientid_arr X-Git-Tag: v7.2~27^2~6 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9e6869be49064915edb6c8776b27c376cfdb0df5;p=thirdparty%2Fkernel%2Flinux.git net/dibs: Correct freeing of dmb_clientid_arr A dibs device interrupt handler can be active after dibs_dev_del() and may still access dmb_clientid_arr. (UAF) In case of a failure in dibs_dev_add() being called by dibs_lo_dev_probe() dmb_clientid_arr is freed twice (double free). Free dmb_clientid_arr in dibs_dev_release() after last reference is gone. Note that allocating in dibs_dev_add() instead of dibs_dev_alloc() is ok for now, because no dmbs can be registered before dibs_dev_add(). Fixes: cc21191b584c ("dibs: Move data path to dibs layer") Cc: stable@vger.kernel.org Co-developed-by: Hidayath Khan Signed-off-by: Hidayath Khan Signed-off-by: Alexandra Winter Reviewed-by: Dust Li Link: https://patch.msgid.link/20260810111432.2334900-1-wintera@linux.ibm.com Signed-off-by: Jakub Kicinski --- diff --git a/drivers/dibs/dibs_loopback.c b/drivers/dibs/dibs_loopback.c index fd5caf1e19a8..649e4e375be3 100644 --- a/drivers/dibs/dibs_loopback.c +++ b/drivers/dibs/dibs_loopback.c @@ -335,7 +335,6 @@ static int dibs_lo_dev_probe(void) return 0; err_reg: - kfree(dibs->dmb_clientid_arr); /* pairs with dibs_dev_alloc() */ put_device(&dibs->dev); kfree(ldev); diff --git a/drivers/dibs/dibs_main.c b/drivers/dibs/dibs_main.c index 4c26fd06973f..2b53a9d277dc 100644 --- a/drivers/dibs/dibs_main.c +++ b/drivers/dibs/dibs_main.c @@ -128,6 +128,7 @@ static void dibs_dev_release(struct device *dev) dibs = container_of(dev, struct dibs_dev, dev); + kfree(dibs->dmb_clientid_arr); kfree(dibs); } @@ -194,12 +195,13 @@ int dibs_dev_add(struct dibs_dev *dibs) ret = device_add(&dibs->dev); if (ret) - goto free_client_arr; + return ret; ret = sysfs_create_group(&dibs->dev.kobj, &dibs_dev_attr_group); if (ret) { dev_err(&dibs->dev, "sysfs_create_group failed for dibs_dev\n"); - goto err_device_del; + device_del(&dibs->dev); + return ret; } mutex_lock(&dibs_dev_list.mutex); mutex_lock(&clients_lock); @@ -214,13 +216,6 @@ int dibs_dev_add(struct dibs_dev *dibs) mutex_unlock(&dibs_dev_list.mutex); return 0; - -err_device_del: - device_del(&dibs->dev); -free_client_arr: - kfree(dibs->dmb_clientid_arr); - return ret; - } EXPORT_SYMBOL_GPL(dibs_dev_add); @@ -247,7 +242,6 @@ void dibs_dev_del(struct dibs_dev *dibs) mutex_unlock(&dibs_dev_list.mutex); device_del(&dibs->dev); - kfree(dibs->dmb_clientid_arr); } EXPORT_SYMBOL_GPL(dibs_dev_del);