[PXEXT] Add PXENV_FILE_EXEC call to PXE extensions API.

This allows pxelinux to execute arbitrary gPXE commands.  This is
remarkably unsafe (not least because some of the commands will assume
full ownership of memory and do nasty things like edit the e820 map
underneath the calling pxelinux), but it does allow access to the
"sanboot" command.

1 files changed, 39 insertions, 1 deletions

diff --git a/src/interface/pxe/pxe_file.c b/src/interface/pxe/pxe_file.c
index 01dac8f7..718f5e38 100644
--- a/src/interface/pxe/pxe_file.c
+++ b/src/interface/pxe/pxe_file.c
@@ -31,7 +31,7 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-FEATURE ( FEATURE_MISC, "PXEXT", DHCP_EB_FEATURE_PXE_EXT, 1 );
+FEATURE ( FEATURE_MISC, "PXEXT", DHCP_EB_FEATURE_PXE_EXT, 2 );
 
 /**
  * FILE OPEN
@@ -189,3 +189,41 @@ PXENV_EXIT_t pxenv_get_file_size ( struct s_PXENV_GET_FILE_SIZE
 	get_file_size->Status = PXENV_STATUS_SUCCESS;
 	return PXENV_EXIT_SUCCESS;
 }
+
+/**
+ * FILE EXEC
+ *
+ * @v file_exec				Pointer to a struct s_PXENV_FILE_EXEC
+ * @v s_PXENV_FILE_EXEC::Command	Command to execute
+ * @ret #PXENV_EXIT_SUCCESS		Command was executed successfully
+ * @ret #PXENV_EXIT_FAILURE		Command was not executed successfully
+ * @ret s_PXENV_FILE_EXEC::Status	PXE status code
+ *
+ */
+PXENV_EXIT_t pxenv_file_exec ( struct s_PXENV_FILE_EXEC *file_exec ) {
+	userptr_t command;
+	size_t command_len;
+	int rc;
+
+	DBG ( "PXENV_FILE_EXEC" );
+
+	/* Copy name from external program, and exec it */
+	command = real_to_user ( file_exec->Command.segment,
+				 file_exec->Command.offset );
+	command_len = strlen_user ( command, 0 );
+	{
+		char command_string[ command_len + 1 ];
+
+		copy_from_user ( command_string, command, 0,
+				 sizeof ( command_string ) );
+		DBG ( " %s", command_string );
+
+		if ( ( rc = system ( command_string ) ) != 0 ) {
+			file_exec->Status = PXENV_STATUS ( rc );
+			return PXENV_EXIT_FAILURE;
+		}
+	}
+
+	file_exec->Status = PXENV_STATUS_SUCCESS;
+	return PXENV_EXIT_SUCCESS;
+}