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Use realpath to clean up arguments to grub-probe

PATCH In review Mario Limonciello 2 participants 2 messages Aug 3, 2011 – Aug 15, 2011

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Mario Limonciello

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#0 lore raw

PATCH 1/1 Use realpath to clean up arguments to grub-probe

Hi,

I've found that the EFI grub-install command can fail to properly figure out devices when using the --root-directory command. This seems to be rooted from a call to grub-probe with a ".." in the path.

This is fixed by using realpath to clean up the path passed in grub-probe. Please see the attached patch.

Thanks,

Signature · 3 lines
*Mario Limonciello*
Linux Engineer
*Dell*| OS Engineering

=== modified file 'ChangeLog'

ChangeLog +5 -0
@@ -1,3 +1,8 @@
+2011-08-02  Mario Limonciello <[email protected]>
+
+	* util/grub-probe.c: Use realpath to clean up directory arguments
+	including '..' such as that used in grub-install for EFI.
+
 2011-07-26  Colin Watson  <[email protected]>
 
 	* configure.ac: The Loongson port requires grub-mkfont due to its

=== modified file 'util/grub-probe.c'

grub-probe.c +12 -1
@@ -42,6 +42,9 @@
 #include <string.h>
 #include <stdlib.h>
 #include <sys/stat.h>
+#ifdef HAVE_LIMITS_H
+#include <limits.h>
+#endif
 
 #define _GNU_SOURCE	1
 #include <getopt.h>

@@ -181,7 +184,15 @@
 #endif
     }
   else
-    device_name = grub_guess_root_device (path);
+    {
+#ifdef PATH_MAX
+      grub_path = xmalloc (PATH_MAX);
+      realpath (path, grub_path);
+#else
+      grub_path = realpath(path, NULL);
+#endif
+    device_name = grub_guess_root_device (grub_path);
+    }
 
   if (! device_name)
     grub_util_error ("cannot find a device for %s (is /dev mounted?)", path);
#1 lore raw
Quoted 6 lines · Mario Limonciello

I've found that the EFI grub-install command can fail to properly figure out devices when using the --root-directory command. This seems to be rooted from a call to grub-probe with a ".." in the path.

This is fixed by using realpath to clean up the path passed in grub-probe. Please see the attached patch.

This would also fix Debian bug #637768 ("grub-probe doesn't follow symlinks").

However, there is no reason to use realpath in new code when canonicalize_file_name exists (and is implemented more safely). I've adjusted your patch to the following and committed it:

=== modified file 'ChangeLog'

ChangeLog +8 -0
@@ -1,3 +1,11 @@
+2011-08-15  Mario Limonciello  <[email protected]>
+2011-08-15  Colin Watson  <[email protected]>
+
+	* util/grub-probe.c (probe): Canonicalise the path argument, fixing
+	use of "/path/.." as in grub-install for EFI as well as handling
+	symlinks correctly.
+	Fixes Debian bug #637768.
+
 2011-08-15  Colin Watson  <[email protected]>
 
 	* util/grub-probe.c: Remove duplicate #include.

=== modified file 'util/grub-probe.c'

grub-probe.c +4 -1
@@ -180,7 +180,10 @@ probe (const char *path, char *device_na
 #endif
     }
   else
-    device_name = grub_guess_root_device (path);
+    {
+      grub_path = canonicalize_file_name (path);
+      device_name = grub_guess_root_device (grub_path);
+    }
 
   if (! device_name)
     grub_util_error ("cannot find a device for %s (is /dev mounted?)", path);

Thanks,

Signature · 1 line
Colin Watson                                       [[email protected]]