Input: limit attributes' output to PAGE_SIZE

sysfs can't handle more than PAGE_SIZE data coming from attributes'
show() methods; make sure we respect this limit.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 24 insertions, 12 deletions

diff --git a/drivers/input/input.c b/drivers/input/input.c
index de94ffcb0995..8dcd3931fa62 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -316,7 +316,8 @@ static struct input_device_id *input_match_device(struct input_device_id *id, st
         return NULL;
 }
 
-static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap, int max)
+static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap,
+                              int max, int add_cr)
 {
         int i;
         int len = 0;
@@ -328,6 +329,10 @@ static int input_print_bitmap(char *buf, int buf_size, unsigned long *bitmap, in
         for (; i >= 0; i--)
                 len += snprintf(buf + len, max(buf_size - len, 0),
                                 "%lx%s", bitmap[i], i > 0 ? " " : "");
+
+        if (add_cr)
+                len += snprintf(buf + len, max(buf_size - len, 0), "\n");
+
         return len;
 }
 
@@ -356,8 +361,7 @@ static unsigned int input_devices_poll(struct file *file, poll_table *wait)
         do {                                                            \
                 len += sprintf(buf + len, "B: %s=", #ev);               \
                 len += input_print_bitmap(buf + len, INT_MAX,           \
-                                        dev->bm##bit, ev##_MAX);        \
-                len += sprintf(buf + len, "\n");                        \
+                                        dev->bm##bit, ev##_MAX, 1);     \
         } while (0)
 
 #define TEST_AND_SPRINTF_BIT(ev, bm)                                    \
@@ -517,7 +521,8 @@ static ssize_t input_dev_show_##name(struct class_device *dev, char *buf)	\
         if (retval)                                                             \
                 return retval;                                                  \
                                                                                 \
-        retval = sprintf(buf, "%s\n", input_dev->name ? input_dev->name : "");  \
+        retval = scnprintf(buf, PAGE_SIZE,                                      \
+                           "%s\n", input_dev->name ? input_dev->name : "");     \
                                                                                 \
         mutex_unlock(&input_dev->mutex);                                        \
                                                                                 \
@@ -541,7 +546,8 @@ static int print_modalias_bits(char *buf, int size, char prefix, unsigned long *
         return len;
 }
 
-static int print_modalias(char *buf, int size, struct input_dev *id)
+static int input_print_modalias(char *buf, int size, struct input_dev *id,
+                                int add_cr)
 {
         int len;
 
@@ -569,6 +575,10 @@ static int print_modalias(char *buf, int size, struct input_dev *id)
                                    0, FF_MAX);
         len += print_modalias_bits(buf + len, size - len, 'w', id->swbit,
                                    0, SW_MAX);
+
+        if (add_cr)
+                len += snprintf(buf + len, size - len, "\n");
+
         return len;
 }
 
@@ -577,9 +587,9 @@ static ssize_t input_dev_show_modalias(struct class_device *dev, char *buf)
         struct input_dev *id = to_input_dev(dev);
         ssize_t len;
 
-        len = print_modalias(buf, PAGE_SIZE, id);
-        len += snprintf(buf + len, PAGE_SIZE-len, "\n");
-        return len;
+        len = input_print_modalias(buf, PAGE_SIZE, id, 1);
+
+        return max_t(int, len, PAGE_SIZE);
 }
 static CLASS_DEVICE_ATTR(modalias, S_IRUGO, input_dev_show_modalias, NULL);
 
@@ -599,7 +609,7 @@ static struct attribute_group input_dev_attr_group = {
 static ssize_t input_dev_show_id_##name(struct class_device *dev, char *buf)    \
 {                                                                               \
         struct input_dev *input_dev = to_input_dev(dev);                        \
-        return sprintf(buf, "%04x\n", input_dev->id.name);                      \
+        return scnprintf(buf, PAGE_SIZE, "%04x\n", input_dev->id.name);         \
 }                                                                               \
 static CLASS_DEVICE_ATTR(name, S_IRUGO, input_dev_show_id_##name, NULL);
 
@@ -625,7 +635,9 @@ static struct attribute_group input_dev_id_attr_group = {
 static ssize_t input_dev_show_cap_##bm(struct class_device *dev, char *buf)     \
 {                                                                               \
         struct input_dev *input_dev = to_input_dev(dev);                        \
-        return input_print_bitmap(buf, PAGE_SIZE, input_dev->bm##bit, ev##_MAX);\
+        int len = input_print_bitmap(buf, PAGE_SIZE,                            \
+                                     input_dev->bm##bit, ev##_MAX, 1);          \
+        return min_t(int, len, PAGE_SIZE);                                      \
 }                                                                               \
 static CLASS_DEVICE_ATTR(bm, S_IRUGO, input_dev_show_cap_##bm, NULL);
 
@@ -684,7 +696,7 @@ static int input_add_uevent_bm_var(char **envp, int num_envp, int *cur_index,
 
         *cur_len += input_print_bitmap(buffer + *cur_len,
                                         max(buffer_size - *cur_len, 0),
-                                        bitmap, max) + 1;
+                                        bitmap, max, 0) + 1;
         if (*cur_len > buffer_size)
                 return -ENOMEM;
 
@@ -747,7 +759,7 @@ static int input_dev_uevent(struct class_device *cdev, char **envp,
 
         envp[i++] = buffer + len;
         len += snprintf(buffer + len, buffer_size - len, "MODALIAS=");
-        len += print_modalias(buffer + len, buffer_size - len, dev) + 1;
+        len += input_print_modalias(buffer + len, buffer_size - len, dev, 0) + 1;
 
         envp[i] = NULL;
         return 0;