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>

diff --git a/drivers/input/input.c b/drivers/input/input.c
index de94ffc..8dcd393 100644 (file)
--- 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;