From 134d3387e1b794bbe1ba1747232f15d9376632c9 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Tue, 16 Mar 2021 12:56:57 +0100 Subject: [PATCH] efi_loader: NULL dereference in EFI console Even if CONFIG_DM_VIDEO=y and stdout="vidconsole", a video device may not be available. Check the return values of the relevant functions. If no video output device is available, assume that the serial console is in use. Signed-off-by: Heinrich Schuchardt --- lib/efi_loader/efi_console.c | 51 +++++++++++++++++++++++++++++++++----------- 1 file changed, 38 insertions(+), 13 deletions(-) diff --git a/lib/efi_loader/efi_console.c b/lib/efi_loader/efi_console.c index c400355..6040f3a 100644 --- a/lib/efi_loader/efi_console.c +++ b/lib/efi_loader/efi_console.c @@ -254,7 +254,7 @@ static bool cout_mode_matches(struct cout_mode *mode, int rows, int cols) } /** - * query_console_serial() - query console size + * query_console_serial() - query serial console size * * When using a serial console or the net console we can only devise the * terminal size by querying the terminal using ECMA-48 control sequences. @@ -300,6 +300,37 @@ out: } /** + * query_vidconsole() - query video console size + * + * + * @rows: pointer to return number of rows + * @cols: pointer to return number of columns + * Returns: 0 on success + */ +static int __maybe_unused query_vidconsole(int *rows, int *cols) +{ + const char *stdout_name = env_get("stdout"); + struct stdio_dev *stdout_dev; + struct udevice *dev; + struct vidconsole_priv *priv; + + if (!stdout_name || strncmp(stdout_name, "vidconsole", 10)) + return -ENODEV; + stdout_dev = stdio_get_by_name("vidconsole"); + if (!stdout_dev) + return -ENODEV; + dev = stdout_dev->priv; + if (!dev) + return -ENODEV; + priv = dev_get_uclass_priv(dev); + if (!priv) + return -ENODEV; + *rows = priv->rows; + *cols = priv->cols; + return 0; +} + +/** * query_console_size() - update the mode table. * * By default the only mode available is 80x25. If the console has at least 50 @@ -308,21 +339,15 @@ out: */ static void query_console_size(void) { - const char *stdout_name = env_get("stdout"); int rows = 25, cols = 80; + int ret = -ENODEV; - if (stdout_name && !strncmp(stdout_name, "vidconsole", 10) && - IS_ENABLED(CONFIG_DM_VIDEO)) { - struct stdio_dev *stdout_dev = - stdio_get_by_name("vidconsole"); - struct udevice *dev = stdout_dev->priv; - struct vidconsole_priv *priv = - dev_get_uclass_priv(dev); - rows = priv->rows; - cols = priv->cols; - } else if (query_console_serial(&rows, &cols)) { + if IS_ENABLED(CONFIG_DM_VIDEO) + ret = query_vidconsole(&rows, &cols); + if (ret) + ret = query_console_serial(&rows, &cols); + if (ret) return; - } /* Test if we can have Mode 1 */ if (cols >= 80 && rows >= 50) { -- 2.7.4