This is a note to let you know that I've just added the patch titled usb: gadget: configfs: Fix memory leak of interface directory data to the 4.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: usb-gadget-configfs-fix-memory-leak-of-interface-directory-data.patch and it can be found in the queue-4.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ff74745e6d3d97a865eda8c1f3fd29c13b79f0cc Mon Sep 17 00:00:00 2001 From: Andrew Gabbasov <andrew_gabbasov@xxxxxxxxxx> Date: Sat, 30 Sep 2017 08:54:52 -0700 Subject: usb: gadget: configfs: Fix memory leak of interface directory data From: Andrew Gabbasov <andrew_gabbasov@xxxxxxxxxx> commit ff74745e6d3d97a865eda8c1f3fd29c13b79f0cc upstream. Kmemleak checking configuration reports a memory leak in usb_os_desc_prepare_interf_dir function when rndis function instance is freed and then allocated again. For example, this happens with FunctionFS driver with RNDIS function enabled when "ffs-test" test application is run several times in a row. The data for intermediate "os_desc" group for interface directories is allocated as a single VLA chunk and (after a change of default groups handling) is not ever freed and actually not stored anywhere besides inside a list of default groups of a parent group. The fix is to make usb_os_desc_prepare_interf_dir function return a pointer to allocated data (as a pointer to the first VLA item) instead of (an unused) integer and to make the caller component (currently the only one is RNDIS function) responsible for storing the pointer and freeing the memory when appropriate. Fixes: 1ae1602de028 ("configfs: switch ->default groups to a linked list") Signed-off-by: Andrew Gabbasov <andrew_gabbasov@xxxxxxxxxx> Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/gadget/configfs.c | 15 ++++++++------- drivers/usb/gadget/configfs.h | 11 ++++++----- drivers/usb/gadget/function/f_rndis.c | 12 ++++++++++-- drivers/usb/gadget/function/u_rndis.h | 1 + 4 files changed, 25 insertions(+), 14 deletions(-) --- a/drivers/usb/gadget/configfs.c +++ b/drivers/usb/gadget/configfs.c @@ -1143,11 +1143,12 @@ static struct configfs_attribute *interf NULL }; -int usb_os_desc_prepare_interf_dir(struct config_group *parent, - int n_interf, - struct usb_os_desc **desc, - char **names, - struct module *owner) +struct config_group *usb_os_desc_prepare_interf_dir( + struct config_group *parent, + int n_interf, + struct usb_os_desc **desc, + char **names, + struct module *owner) { struct config_group *os_desc_group; struct config_item_type *os_desc_type, *interface_type; @@ -1159,7 +1160,7 @@ int usb_os_desc_prepare_interf_dir(struc char *vlabuf = kzalloc(vla_group_size(data_chunk), GFP_KERNEL); if (!vlabuf) - return -ENOMEM; + return ERR_PTR(-ENOMEM); os_desc_group = vla_ptr(vlabuf, data_chunk, os_desc_group); os_desc_type = vla_ptr(vlabuf, data_chunk, os_desc_type); @@ -1184,7 +1185,7 @@ int usb_os_desc_prepare_interf_dir(struc configfs_add_default_group(&d->group, os_desc_group); } - return 0; + return os_desc_group; } EXPORT_SYMBOL(usb_os_desc_prepare_interf_dir); --- a/drivers/usb/gadget/configfs.h +++ b/drivers/usb/gadget/configfs.h @@ -5,11 +5,12 @@ void unregister_gadget_item(struct config_item *item); -int usb_os_desc_prepare_interf_dir(struct config_group *parent, - int n_interf, - struct usb_os_desc **desc, - char **names, - struct module *owner); +struct config_group *usb_os_desc_prepare_interf_dir( + struct config_group *parent, + int n_interf, + struct usb_os_desc **desc, + char **names, + struct module *owner); static inline struct usb_os_desc *to_usb_os_desc(struct config_item *item) { --- a/drivers/usb/gadget/function/f_rndis.c +++ b/drivers/usb/gadget/function/f_rndis.c @@ -892,6 +892,7 @@ static void rndis_free_inst(struct usb_f free_netdev(opts->net); } + kfree(opts->rndis_interf_group); /* single VLA chunk */ kfree(opts); } @@ -900,6 +901,7 @@ static struct usb_function_instance *rnd struct f_rndis_opts *opts; struct usb_os_desc *descs[1]; char *names[1]; + struct config_group *rndis_interf_group; opts = kzalloc(sizeof(*opts), GFP_KERNEL); if (!opts) @@ -920,8 +922,14 @@ static struct usb_function_instance *rnd names[0] = "rndis"; config_group_init_type_name(&opts->func_inst.group, "", &rndis_func_type); - usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs, - names, THIS_MODULE); + rndis_interf_group = + usb_os_desc_prepare_interf_dir(&opts->func_inst.group, 1, descs, + names, THIS_MODULE); + if (IS_ERR(rndis_interf_group)) { + rndis_free_inst(&opts->func_inst); + return ERR_CAST(rndis_interf_group); + } + opts->rndis_interf_group = rndis_interf_group; return &opts->func_inst; } --- a/drivers/usb/gadget/function/u_rndis.h +++ b/drivers/usb/gadget/function/u_rndis.h @@ -26,6 +26,7 @@ struct f_rndis_opts { bool bound; bool borrowed_net; + struct config_group *rndis_interf_group; struct usb_os_desc rndis_os_desc; char rndis_ext_compat_id[16]; Patches currently in stable-queue which might be from andrew_gabbasov@xxxxxxxxxx are queue-4.13/usb-gadget-composite-fix-use-after-free-in-usb_composite_overwrite_options.patch queue-4.13/usb-gadget-configfs-fix-memory-leak-of-interface-directory-data.patch