4.9-stable review patch. If anyone has any objections, please let me know.
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From: Sven Eckelmann sven@narfation.org
[ Upstream commit a25bab9d723a08bd0bdafb1529faf9094c690b70 ]
The per hardif sysfs file "batman_adv/elp_interval" is using the generic functions to store/show uint values. The helper __batadv_store_uint_attr requires the softif net_device as parameter to print the resulting change as info text when the users writes to this file. It uses the helper function batadv_info to add it at the same time to the kernel ring buffer and to the batman-adv debug log (when CONFIG_BATMAN_ADV_DEBUG is enabled).
The function batadv_info requires as first parameter the batman-adv softif net_device. This parameter is then used to find the private buffer which contains the debug log for this batman-adv interface. But batadv_store_throughput_override used as first argument the slave net_device. This slave device doesn't have the batadv_priv private data which is access by batadv_info.
Writing to this file with CONFIG_BATMAN_ADV_DEBUG enabled can either lead to a segfault or to memory corruption.
Fixes: 0744ff8fa8fa ("batman-adv: Add hard_iface specific sysfs wrapper macros for UINT") Signed-off-by: Sven Eckelmann sven@narfation.org Acked-by: Marek Lindner mareklindner@neomailbox.ch Signed-off-by: Simon Wunderlich sw@simonwunderlich.de Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/batman-adv/sysfs.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)
--- a/net/batman-adv/sysfs.c +++ b/net/batman-adv/sysfs.c @@ -187,7 +187,8 @@ ssize_t batadv_store_##_name(struct kobj \ return __batadv_store_uint_attr(buff, count, _min, _max, \ _post_func, attr, \ - &bat_priv->_var, net_dev); \ + &bat_priv->_var, net_dev, \ + NULL); \ }
#define BATADV_ATTR_SIF_SHOW_UINT(_name, _var) \ @@ -261,7 +262,9 @@ ssize_t batadv_store_##_name(struct kobj \ length = __batadv_store_uint_attr(buff, count, _min, _max, \ _post_func, attr, \ - &hard_iface->_var, net_dev); \ + &hard_iface->_var, \ + hard_iface->soft_iface, \ + net_dev); \ \ batadv_hardif_put(hard_iface); \ return length; \ @@ -355,10 +358,12 @@ __batadv_store_bool_attr(char *buff, siz
static int batadv_store_uint_attr(const char *buff, size_t count, struct net_device *net_dev, + struct net_device *slave_dev, const char *attr_name, unsigned int min, unsigned int max, atomic_t *attr) { + char ifname[IFNAMSIZ + 3] = ""; unsigned long uint_val; int ret;
@@ -384,8 +389,11 @@ static int batadv_store_uint_attr(const if (atomic_read(attr) == uint_val) return count;
- batadv_info(net_dev, "%s: Changing from: %i to: %lu\n", - attr_name, atomic_read(attr), uint_val); + if (slave_dev) + snprintf(ifname, sizeof(ifname), "%s: ", slave_dev->name); + + batadv_info(net_dev, "%s: %sChanging from: %i to: %lu\n", + attr_name, ifname, atomic_read(attr), uint_val);
atomic_set(attr, uint_val); return count; @@ -396,12 +404,13 @@ static ssize_t __batadv_store_uint_attr( void (*post_func)(struct net_device *), const struct attribute *attr, atomic_t *attr_store, - struct net_device *net_dev) + struct net_device *net_dev, + struct net_device *slave_dev) { int ret;
- ret = batadv_store_uint_attr(buff, count, net_dev, attr->name, min, max, - attr_store); + ret = batadv_store_uint_attr(buff, count, net_dev, slave_dev, + attr->name, min, max, attr_store); if (post_func && ret) post_func(net_dev);
@@ -570,7 +579,7 @@ static ssize_t batadv_store_gw_sel_class return __batadv_store_uint_attr(buff, count, 1, BATADV_TQ_MAX_VALUE, batadv_post_gw_reselect, attr, &bat_priv->gw.sel_class, - bat_priv->soft_iface); + bat_priv->soft_iface, NULL); }
static ssize_t batadv_show_gw_bwidth(struct kobject *kobj,