2 files changed, 55 insertions, 26 deletions

diff --git a/drivers/firmware/sigma.c b/drivers/firmware/sigma.c
index f10fc521951b..c780baa59ed9 100644
--- a/drivers/firmware/sigma.c
+++ b/drivers/firmware/sigma.c
@@ -14,13 +14,34 @@
 #include <linux/module.h>
 #include <linux/sigma.h>
 
-/* Return: 0==OK, <0==error, =1 ==no more actions */
+static size_t sigma_action_size(struct sigma_action *sa)
+{
+        size_t payload = 0;
+
+        switch (sa->instr) {
+        case SIGMA_ACTION_WRITEXBYTES:
+        case SIGMA_ACTION_WRITESINGLE:
+        case SIGMA_ACTION_WRITESAFELOAD:
+                payload = sigma_action_len(sa);
+                break;
+        default:
+                break;
+        }
+
+        payload = ALIGN(payload, 2);
+
+        return payload + sizeof(struct sigma_action);
+}
+
+/*
+ * Returns a negative error value in case of an error, 0 if processing of
+ * the firmware should be stopped after this action, 1 otherwise.
+ */
 static int
-process_sigma_action(struct i2c_client *client, struct sigma_firmware *ssfw)
+process_sigma_action(struct i2c_client *client, struct sigma_action *sa)
 {
-        struct sigma_action *sa = (void *)(ssfw->fw->data + ssfw->pos);
         size_t len = sigma_action_len(sa);
-        int ret = 0;
+        int ret;
 
         pr_debug("%s: instr:%i addr:%#x len:%zu\n", __func__,
                 sa->instr, sa->addr, len);
@@ -29,44 +50,50 @@ process_sigma_action(struct i2c_client *client, struct sigma_firmware *ssfw)
         case SIGMA_ACTION_WRITEXBYTES:
         case SIGMA_ACTION_WRITESINGLE:
         case SIGMA_ACTION_WRITESAFELOAD:
-                if (ssfw->fw->size < ssfw->pos + len)
-                        return -EINVAL;
                 ret = i2c_master_send(client, (void *)&sa->addr, len);
                 if (ret < 0)
                         return -EINVAL;
                 break;
-
         case SIGMA_ACTION_DELAY:
-                ret = 0;
                 udelay(len);
                 len = 0;
                 break;
-
         case SIGMA_ACTION_END:
-                return 1;
-
+                return 0;
         default:
                 return -EINVAL;
         }
 
-        /* when arrive here ret=0 or sent data */
-        ssfw->pos += sigma_action_size(sa, len);
-        return ssfw->pos == ssfw->fw->size;
+        return 1;
 }
 
 static int
 process_sigma_actions(struct i2c_client *client, struct sigma_firmware *ssfw)
 {
-        pr_debug("%s: processing %p\n", __func__, ssfw);
+        struct sigma_action *sa;
+        size_t size;
+        int ret;
+
+        while (ssfw->pos + sizeof(*sa) <= ssfw->fw->size) {
+                sa = (struct sigma_action *)(ssfw->fw->data + ssfw->pos);
+
+                size = sigma_action_size(sa);
+                ssfw->pos += size;
+                if (ssfw->pos > ssfw->fw->size || size == 0)
+                        break;
+
+                ret = process_sigma_action(client, sa);
 
-        while (1) {
-                int ret = process_sigma_action(client, ssfw);
                 pr_debug("%s: action returned %i\n", __func__, ret);
-                if (ret == 1)
-                        return 0;
-                else if (ret)
+
+                if (ret <= 0)
                         return ret;
         }
+
+        if (ssfw->pos != ssfw->fw->size)
+                return -EINVAL;
+
+        return 0;
 }
 
 int process_sigma_firmware(struct i2c_client *client, const char *name)
@@ -89,7 +116,14 @@ int process_sigma_firmware(struct i2c_client *client, const char *name)
 
         /* then verify the header */
         ret = -EINVAL;
-        if (fw->size < sizeof(*ssfw_head))
+
+        /*
+         * Reject too small or unreasonable large files. The upper limit has been
+         * chosen a bit arbitrarily, but it should be enough for all practical
+         * purposes and having the limit makes it easier to avoid integer
+         * overflows later in the loading process.
+         */
+        if (fw->size < sizeof(*ssfw_head) || fw->size >= 0x4000000)
                 goto done;
 
         ssfw_head = (void *)fw->data;
diff --git a/include/linux/sigma.h b/include/linux/sigma.h
index e2accb3164d8..9a138c2946bb 100644
--- a/include/linux/sigma.h
+++ b/include/linux/sigma.h
@@ -50,11 +50,6 @@ static inline u32 sigma_action_len(struct sigma_action *sa)
         return (sa->len_hi << 16) | sa->len;
 }
 
-static inline size_t sigma_action_size(struct sigma_action *sa, u32 payload_len)
-{
-        return sizeof(*sa) + payload_len + (payload_len % 2);
-}
-
 extern int process_sigma_firmware(struct i2c_client *client, const char *name);
 
 #endif