[efi] Add excessive sanity checks into efi_debug functions

Try very hard to avoid ever doing something invalid while attempting
to generate a debug message.

Debugged-by: Curtis Larsen <larsen@dixie.edu>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/interface/efi/efi_debug.c b/src/interface/efi/efi_debug.c
index e5ecfe373e8c2c225b16d8934ed12f68f5dbfc9e..a3d2438fef040331a44f6b105f61e1b3f1a2dd05 100644 (file)
--- a/src/interface/efi/efi_debug.c
+++ b/src/interface/efi/efi_debug.c
@@ -168,6 +168,10 @@ const char * efi_guid_ntoa ( EFI_GUID *guid ) {
        } u;
        unsigned int i;
 
+       /* Sanity check */
+       if ( ! guid )
+               return NULL;
+
        /* Check for a match against well-known GUIDs */
        for ( i = 0 ; i < ( sizeof ( efi_well_known_guids ) /
                            sizeof ( efi_well_known_guids[0] ) ) ; i++ ) {
@@ -224,6 +228,13 @@ void dbg_efi_openers ( EFI_HANDLE handle, EFI_GUID *protocol ) {
        EFI_STATUS efirc;
        int rc;
 
+       /* Sanity check */
+       if ( ( ! handle ) || ( ! protocol ) ) {
+               printf ( "EFI could not retrieve openers for %s on %p\n",
+                        efi_guid_ntoa ( protocol ), handle );
+               return;
+       }
+
        /* Retrieve list of openers */
        if ( ( efirc = bs->OpenProtocolInformation ( handle, protocol, &openers,
                                                     &count ) ) != 0 ) {
@@ -268,6 +279,12 @@ void dbg_efi_protocols ( EFI_HANDLE handle ) {
        EFI_STATUS efirc;
        int rc;
 
+       /* Sanity check */
+       if ( ! handle ) {
+               printf ( "EFI could not retrieve protocols for %p\n", handle );
+               return;
+       }
+
        /* Retrieve list of protocols */
        if ( ( efirc = bs->ProtocolsPerHandle ( handle, &protocols,
                                                &count ) ) != 0 ) {
@@ -301,9 +318,17 @@ const char * efi_devpath_text ( EFI_DEVICE_PATH_PROTOCOL *path ) {
        static char text[256];
        CHAR16 *wtext;
 
-       /* Convert path to a textual representation */
-       if ( ! efidpt )
+       /* Sanity checks */
+       if ( ! efidpt ) {
+               DBG ( "[No DevicePathToText]" );
+               return NULL;
+       }
+       if ( ! path ) {
+               DBG ( "[NULL DevicePath]" );
                return NULL;
+       }
+
+       /* Convert path to a textual representation */
        wtext = efidpt->ConvertDevicePathToText ( path, TRUE, FALSE );
        if ( ! wtext )
                return NULL;
@@ -328,6 +353,12 @@ static const char * efi_driver_name ( EFI_COMPONENT_NAME2_PROTOCOL *wtf ) {
        CHAR16 *driver_name;
        EFI_STATUS efirc;
 
+       /* Sanity check */
+       if ( ! wtf ) {
+               DBG ( "[NULL ComponentName2]" );
+               return NULL;
+       }
+
        /* Try "en" first; if that fails then try the first language */
        if ( ( ( efirc = wtf->GetDriverName ( wtf, "en",
                                              &driver_name ) ) != 0 ) &&
@@ -350,7 +381,7 @@ static const char * efi_driver_name ( EFI_COMPONENT_NAME2_PROTOCOL *wtf ) {
 static const char *
 efi_pecoff_debug_name ( EFI_LOADED_IMAGE_PROTOCOL *loaded ) {
        static char buf[32];
-       EFI_IMAGE_DOS_HEADER *dos = loaded->ImageBase;
+       EFI_IMAGE_DOS_HEADER *dos;
        EFI_IMAGE_OPTIONAL_HEADER_UNION *pe;
        EFI_IMAGE_OPTIONAL_HEADER32 *opt32;
        EFI_IMAGE_OPTIONAL_HEADER64 *opt64;
@@ -367,7 +398,14 @@ efi_pecoff_debug_name ( EFI_LOADED_IMAGE_PROTOCOL *loaded ) {
        char *name;
        char *tmp;
 
+       /* Sanity check */
+       if ( ! loaded ) {
+               DBG ( "[NULL LoadedImage]" );
+               return NULL;
+       }
+
        /* Parse DOS header */
+       dos = loaded->ImageBase;
        if ( ! dos ) {
                DBG ( "[Missing DOS header]" );
                return NULL;
@@ -462,6 +500,12 @@ efi_pecoff_debug_name ( EFI_LOADED_IMAGE_PROTOCOL *loaded ) {
 static const char *
 efi_first_loaded_image_name ( EFI_LOADED_IMAGE_PROTOCOL *loaded ) {
 
+       /* Sanity check */
+       if ( ! loaded ) {
+               DBG ( "[NULL LoadedImage]" );
+               return NULL;
+       }
+
        return ( ( loaded->ParentHandle == NULL ) ? "DxeCore(?)" : NULL );
 }
 
@@ -474,6 +518,12 @@ efi_first_loaded_image_name ( EFI_LOADED_IMAGE_PROTOCOL *loaded ) {
 static const char *
 efi_loaded_image_filepath_name ( EFI_LOADED_IMAGE_PROTOCOL *loaded ) {
 
+       /* Sanity check */
+       if ( ! loaded ) {
+               DBG ( "[NULL LoadedImage]" );
+               return NULL;
+       }
+
        return efi_devpath_text ( loaded->FilePath );
 }