Blame SOURCES/0440-gfxmenu-gui-Check-printf-format-in-the-gui_progress_.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Thomas Frauendorfer | Miray Software <tf@miray.de>
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Date: Tue, 4 Aug 2020 13:49:51 +0200
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Subject: [PATCH] gfxmenu/gui: Check printf() format in the gui_progress_bar
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 and gui_label
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The gui_progress_bar and gui_label components can display the timeout
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value. The format string can be set through a theme file. This patch
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adds a validation step to the format string.
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If a user loads a theme file into the GRUB without this patch then
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a GUI label with the following settings
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  + label {
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  ...
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  id = "__timeout__"
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  text = "%s"
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  }
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will interpret the current timeout value as string pointer and print the
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memory at that position on the screen. It is not desired behavior.
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Signed-off-by: Thomas Frauendorfer | Miray Software <tf@miray.de>
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Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
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---
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 grub-core/gfxmenu/gui_label.c        | 4 ++++
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 grub-core/gfxmenu/gui_progress_bar.c | 3 +++
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 2 files changed, 7 insertions(+)
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diff --git a/grub-core/gfxmenu/gui_label.c b/grub-core/gfxmenu/gui_label.c
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index a4c817891ee..1c190542a2b 100644
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--- a/grub-core/gfxmenu/gui_label.c
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+++ b/grub-core/gfxmenu/gui_label.c
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@@ -193,6 +193,10 @@ label_set_property (void *vself, const char *name, const char *value)
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 	   else if (grub_strcmp (value, "@KEYMAP_SHORT@") == 0)
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 	    value = _("enter: boot, `e': options, `c': cmd-line");
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 	   /* FIXME: Add more templates here if needed.  */
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+
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+	  if (grub_printf_fmt_check(value, "%d") != GRUB_ERR_NONE)
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+	    value = ""; /* Unsupported format. */
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+
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 	  self->template = grub_strdup (value);
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 	  self->text = grub_xasprintf (value, self->value);
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 	}
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diff --git a/grub-core/gfxmenu/gui_progress_bar.c b/grub-core/gfxmenu/gui_progress_bar.c
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index 3501b01724f..048275e036e 100644
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--- a/grub-core/gfxmenu/gui_progress_bar.c
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+++ b/grub-core/gfxmenu/gui_progress_bar.c
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@@ -342,6 +342,9 @@ progress_bar_set_property (void *vself, const char *name, const char *value)
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 	   Please use the shortest form available in you language.  */
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 	value = _("%ds");
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+      if (grub_printf_fmt_check(value, "%d") != GRUB_ERR_NONE)
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+	value = ""; /* Unsupported format. */
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+
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       self->template = grub_strdup (value);
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     }
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   else if (grub_strcmp (name, "font") == 0)