Filling return value, still left to return it from IOCTL

carmeli-tamir · Sep 14, 2019 · e1a43e9 · e1a43e9
1 parent 561832b
commit e1a43e9
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Showing 6 changed files with 53 additions and 56 deletions.
diff --git a/TODO b/TODO
@@ -1,10 +1,14 @@
-0. Fix repo.sh: Don't insmod modules if they're loaded
-1. Implement return type
+1. Implement return type; Left to return it from the ioctl and parse it in python
 2. Implement parse_proto_and_call_function_fourByteArg1
-3. Implement 2 args function
+3. Remove demo code from main
 4. Write code to auto - generate function calls
-5. write tests?
+5. Improve documentation and open project to the public
+6. Re-write skunk.py as a class
+7. Implement 2 args function
+8. write tests
+9. Enforce clang formatting
+10. Support return values other than 8 bytes
 
 
-Return: void X u32 X u64 X char* (Return message, each is optional)
+Return: void X NUM (32bit / 64bit / ptr) X char* (Return message, each is optional)
 Args: char* X u32 X u64 (Repeated proto. Code arguments in Arguments)
diff --git a/kernel/call_functions.c b/kernel/call_functions.c
@@ -5,12 +5,45 @@
 
 #include "skunk.pb-c.h"
 
+static void parse_proto_and_call_function_ret_64_stringArg1(char *buffer, u32 length, Skunk__ReturnValue *ret)
+{
+    Skunk__FuncWith1Arg *func_1arg;
+    u32 message_size;
+    u32 offset = 0;
+    unsigned long func_addr;
+
+    message_size = *((u32*)buffer);
+    offset = sizeof(message_size);
+    if (message_size < 0 || message_size > length - offset) {
+        ret->status = SKUNK__RETURN_VALUE__CALL_STATUS__BadProtobufMessage;
+    }
+
+    func_1arg = skunk__func_with_1_arg__unpack(NULL, message_size, buffer + sizeof(message_size));
+    if (NULL == func_1arg) {
+        ret->status = SKUNK__RETURN_VALUE__CALL_STATUS__BadProtobufMessage;
+    }
+
+    func_addr = kallsyms_lookup_name(func_1arg->name);
+    if (0 == func_addr) {
+        ret->status = SKUNK__RETURN_VALUE__CALL_STATUS__FunctionDoesntExist;
+    }
+    ret->ret64 =(int64_t)((ptrRet64OneArg)func_addr)(func_1arg->arg1);
+}
+
+static void parse_proto_and_call_function_ret_64_fourByteArg1(char *buffer, u32 length)
+{
+    pr_info("Hello four byte arg1");
+}
+
 long parse_user_buffer_and_call_function(char *buffer, u32 length)
 {
     Skunk__FunctionType *func_type;
+    Skunk__ReturnValue ret;
     u32 message_size;
     u32 offset = 0;
 
+    skunk__return_value__init(&ret);
+
     message_size = *((u32*)buffer);
     offset = sizeof(message_size);
     if (message_size < 0 || message_size > length - offset) {
@@ -22,62 +55,25 @@ long parse_user_buffer_and_call_function(char *buffer, u32 length)
         return -EINVAL;
     }
 
-    if (func_type->ret != SKUNK__FUNCTION_TYPE__RETURN_TYPE__fourByte) {
-        //TODO: Handle non 4 bytes return values
+    if (func_type->ret != SKUNK__FUNCTION_TYPE__RETURN_TYPE__eightByte) {
         pr_info("Currently supporting only 4 bytes return value");
+        skunk__function_type__free_unpacked(func_type, NULL);
         return -EINVAL;
     }
 
     switch (func_type->args)
     {
         case SKUNK__FUNCTION_TYPE__ARGUMENTS__stringArg1:
-            //TODO: Pack return value
-            parse_proto_and_call_function_stringArg1(buffer + offset + message_size, length - offset);
+            parse_proto_and_call_function_ret_64_stringArg1(buffer + offset + message_size, length - offset, &ret);
         break;
         case SKUNK__FUNCTION_TYPE__ARGUMENTS__fourByteArg1:
-            parse_proto_and_call_function_fourByteArg1(buffer + offset + message_size, length - offset);
+            parse_proto_and_call_function_ret_64_fourByteArg1(buffer + offset + message_size, length - offset);
         break;
     default:
         break;
     }
 
-    return 0;
-}
-
-
-u32 parse_proto_and_call_function_stringArg1(char *buffer, u32 length)
-{
-    Skunk__FuncWith1Arg *func_1arg;
-    u32 message_size;
-    u32 offset = 0;
-    u64 ret = 0;
-    unsigned long func_addr;
-
-    message_size = *((u32*)buffer);
-    offset = sizeof(message_size);
-    if (message_size < 0 || message_size > length - offset) {
-        return message_size;
-    }
-
-    func_1arg = skunk__func_with_1_arg__unpack(NULL, message_size, buffer + sizeof(message_size));
-    if (NULL == func_1arg) {
-        return -EINVAL;
-    }
-
-    func_addr = kallsyms_lookup_name(func_1arg->name);
-    if (0 == func_addr) {
-        return -EINVAL;
-    }
-
-    ret =(u64) ((ptrRet64OneArg)func_addr)(func_1arg->arg1);
-
-    pr_info("Got ret value of %p", (void*)ret);
+    skunk__function_type__free_unpacked(func_type, NULL);
 
     return 0;
 }
-
-u32 parse_proto_and_call_function_fourByteArg1(char *buffer, u32 length)
-{
-    pr_info("Hello four byte arg1");
-    return 0;
-}
diff --git a/kernel/skunk.h b/kernel/skunk.h
@@ -13,8 +13,4 @@ typedef u64 (*ptrRet64OneArg)(void *arg1);
 
 long parse_user_buffer_and_call_function(char *buffer, u32 length);
 
-u32 parse_proto_and_call_function_stringArg1(char *buffer, u32 length);
-
-u32 parse_proto_and_call_function_fourByteArg1(char *buffer, u32 length);
-
 #endif /* SKUNK_H */
diff --git a/kernel/skunk_device.c b/kernel/skunk_device.c
@@ -33,6 +33,7 @@ static long ioctl_skunk_device(struct file *file, unsigned int cmd, unsigned lon
             return -ENOMEM;
         }
         if (copy_from_user(message, ((char*)arg ) + sizeof(message_size), message_size)) {
+            kfree(message);
             return -ENOMEM;
         }
         ret = parse_user_buffer_and_call_function(message, message_size);

diff --git a/skunk.proto b/skunk.proto
@@ -9,7 +9,7 @@ message function_type {
   }
 
 enum ReturnType {
-    fourByte = 0;
+    eightByte = 0;
   }
     required Arguments args = 1;
     required ReturnType ret = 2;
@@ -19,11 +19,11 @@ message ReturnValue {
   enum CallStatus {
     Success = 0;
     FunctionDoesntExist = 1;
+    BadProtobufMessage = 2;
   }
     required CallStatus status = 1;
-    optional int32 ret32 = 2;
-    optional int64 ret64 = 3;
-    optional string retString = 4;
+    optional int64 ret64 = 2;
+    optional string retString = 3;
 }
 
 message func_with_1_arg {

diff --git a/user/skunk.py b/user/skunk.py
@@ -25,7 +25,7 @@ def call_function_demo(device, fname, fargs, fret, arg1):
 
 def run_skunk():
     with open("/dev/skunk", 'r') as skunk_device:
-        call_function_demo(skunk_device, "kallsyms_lookup_name", skunk_pb2.function_type.stringArg1, skunk_pb2.function_type.fourByte, "kallsyms_lookup_name")
+        call_function_demo(skunk_device, "kallsyms_lookup_name", skunk_pb2.function_type.stringArg1, skunk_pb2.function_type.eightByte, "kallsyms_lookup_name")
 
 
 if __name__ == "__main__":