From b62f2325ba2bc4cfacf9d4ce1db6fd37cd966f9c Mon Sep 17 00:00:00 2001
From: Michael Brown <mcb30@etherboot.org>
Date: Tue, 4 Mar 2008 18:16:30 +0000
Subject: [PATCH] [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.
---
 src/arch/i386/interface/pxe/pxe_call.c |  5 ++++
 src/include/pxe.h                      |  1 +
 src/include/pxe_api.h                  | 22 ++++++++++++++
 src/interface/pxe/pxe_file.c           | 40 +++++++++++++++++++++++++-
 4 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/src/arch/i386/interface/pxe/pxe_call.c b/src/arch/i386/interface/pxe/pxe_call.c
index 8f1dd0a2..b9c21ce5 100644
--- a/src/arch/i386/interface/pxe/pxe_call.c
+++ b/src/arch/i386/interface/pxe/pxe_call.c
@@ -96,6 +96,7 @@ union pxenv_call {
 	PXENV_EXIT_t ( * file_select ) ( struct s_PXENV_FILE_SELECT * );
 	PXENV_EXIT_t ( * file_read ) ( struct s_PXENV_FILE_READ * );
 	PXENV_EXIT_t ( * get_file_size ) ( struct s_PXENV_GET_FILE_SIZE * );
+	PXENV_EXIT_t ( * file_exec ) ( struct s_PXENV_FILE_EXEC * );
 };
 
 /**
@@ -294,6 +295,10 @@ __cdecl void pxe_api_call ( struct i386_all_regs *ix86 ) {
 		pxenv_call.get_file_size = pxenv_get_file_size;
 		param_len = sizeof ( pxenv_any.get_file_size );
 		break;
+	case PXENV_FILE_EXEC:
+		pxenv_call.file_exec = pxenv_file_exec;
+		param_len = sizeof ( pxenv_any.file_exec );
+		break;
 	default:
 		DBG ( "PXENV_UNKNOWN_%hx", opcode );
 		pxenv_call.unknown = pxenv_unknown;
diff --git a/src/include/pxe.h b/src/include/pxe.h
index f17d8f77..8b3ca14c 100644
--- a/src/include/pxe.h
+++ b/src/include/pxe.h
@@ -63,6 +63,7 @@ union u_PXENV_ANY {
 	struct s_PXENV_FILE_SELECT		file_select;
 	struct s_PXENV_FILE_READ		file_read;
 	struct s_PXENV_GET_FILE_SIZE		get_file_size;
+	struct s_PXENV_FILE_EXEC		file_exec;
 };
 
 typedef union u_PXENV_ANY PXENV_ANY_t;
diff --git a/src/include/pxe_api.h b/src/include/pxe_api.h
index 8dc1607a..53708ed4 100644
--- a/src/include/pxe_api.h
+++ b/src/include/pxe_api.h
@@ -1684,6 +1684,28 @@ extern PXENV_EXIT_t pxenv_get_file_size ( struct s_PXENV_GET_FILE_SIZE
 
 /** @} */ /* pxenv_get_file_size */
 
+/** @defgroup pxenv_file_exec PXENV_FILE_EXEC
+ *
+ * FILE EXEC
+ *
+ * @{
+ */
+
+/** PXE API function code for pxenv_file_exec() */
+#define PXENV_FILE_EXEC			0x00e5
+
+/** Parameter block for pxenv_file_exec() */
+struct s_PXENV_FILE_EXEC {
+	PXENV_STATUS_t Status;		/**< PXE status code */
+	SEGOFF16_t Command;		/**< Command to execute */
+} PACKED;
+
+typedef struct s_PXENV_FILE_EXEC PXENV_FILE_EXEC_t;
+
+extern PXENV_EXIT_t pxenv_file_exec ( struct s_PXENV_FILE_EXEC *file_exec );
+
+/** @} */ /* pxenv_file_exec */
+
 /** @} */ /* pxe_file_api */
 
 /** @defgroup pxe_loader_api PXE Loader API
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;
+}