efi_loader: don't use unlimited stack as buffer

The length of a string printed to the console by the
EFI_SIMPLE_TEXT_OUTPUT_PROTOCOL is not limited by the UEFI spec.
Hence should not allocate a buffer for it on the stack.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Alexander Graf <agraf@suse.de>

diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c
index f3d6128..f5f3f25 100644 (file)
--- a/lib/efi_loader/efi_console.c
+++ b/lib/efi_loader/efi_console.c
@@ -111,16 +111,21 @@ static efi_status_t EFIAPI efi_cout_output_string(
 {
        struct simple_text_output_mode *con = &efi_con_mode;
        struct cout_mode *mode = &efi_cout_modes[con->mode];
-
-       EFI_ENTRY("%p, %p", this, string);
-
-       unsigned int n16 = u16_strlen(string);
-       char buf[MAX_UTF8_PER_UTF16 * n16 + 1];
+       char *buf, *pos;
        u16 *p;
+       efi_status_t ret = EFI_SUCCESS;
 
-       *utf16_to_utf8((u8 *)buf, string, n16) = '\0';
+       EFI_ENTRY("%p, %p", this, string);
 
+       buf = malloc(utf16_utf8_strlen(string) + 1);
+       if (!buf) {
+               ret = EFI_OUT_OF_RESOURCES;
+               goto out;
+       }
+       pos = buf;
+       utf16_utf8_strcpy(&pos, string);
        fputs(stdout, buf);
+       free(buf);
 
        /*
         * Update the cursor position.
@@ -158,7 +163,8 @@ static efi_status_t EFIAPI efi_cout_output_string(
                con->cursor_row = min(con->cursor_row, (s32)mode->rows - 1);
        }
 
-       return EFI_EXIT(EFI_SUCCESS);
+out:
+       return EFI_EXIT(ret);
 }
 
 static efi_status_t EFIAPI efi_cout_test_string(