[PATCH] Generalize MD_MAX_DISKS to GRUB_MDRAID_MAX_DISKS

[PATCH] Generalize MD_MAX_DISKS to GRUB_MDRAID_MAX_DISKS

[Julian Andres Klode]

Move the constant from getroot.c to disk.h and then reuse
it place of the hardcoded 1024 limit in diskfilter.

Fixes: 2a5e3c1f2 (disk/diskfilter: Don't make a RAID array with more than 1024 disks)
Cc: Daniel Axtens <dja@axtens.net>
Cc: Kees Cook <keescook@chromium.org>
---
 grub-core/disk/diskfilter.c     |  4 ++--
 grub-core/osdep/linux/getroot.c | 12 ++----------
 include/grub/disk.h             | 10 ++++++++++
 3 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/grub-core/disk/diskfilter.c b/grub-core/disk/diskfilter.c
index 1c568927b..61a311efd 100644
--- a/grub-core/disk/diskfilter.c
+++ b/grub-core/disk/diskfilter.c
@@ -1046,8 +1046,8 @@ grub_diskfilter_make_raid (grub_size_t uuidlen, char *uuid, int nmemb,
   struct grub_diskfilter_pv *pv;
   grub_err_t err;
 
-  /* We choose not to support more than 1024 disks. */
-  if (nmemb < 1 || nmemb > 1024)
+  /* We choose not to support more than the specified number of disks. */
+  if (nmemb < 1 || nmemb > GRUB_MDRAID_MAX_DISKS)
     {
       grub_free (uuid);
       return NULL;
diff --git a/grub-core/osdep/linux/getroot.c b/grub-core/osdep/linux/getroot.c
index 9cf037ec2..7dd775d2a 100644
--- a/grub-core/osdep/linux/getroot.c
+++ b/grub-core/osdep/linux/getroot.c
@@ -44,6 +44,7 @@
 
 #include <grub/mm.h>
 #include <grub/misc.h>
+#include <grub/disk.h>
 #include <grub/emu/misc.h>
 #include <grub/emu/hostdisk.h>
 #include <grub/emu/getroot.h>
@@ -130,15 +131,6 @@ struct mountinfo_entry
   char fstype[ESCAPED_PATH_MAX + 1], device[ESCAPED_PATH_MAX + 1];
 };
 
-/*
- * GET_DISK_INFO nr_disks (total count) does not map to disk.number,
- * which is an internal kernel index. Instead, do what mdadm does
- * and keep scanning until we find enough valid disks. The limit is
- * copied from there, which notes that it is sufficiently high given
- * that the on-disk metadata for v1.x can only support 1920.
- */
-#define MD_MAX_DISKS       4096
-
 static char **
 grub_util_raid_getmembers (const char *name, int bootable)
 {
@@ -176,7 +168,7 @@ grub_util_raid_getmembers (const char *name, int bootable)
   devicelist = xcalloc (info.nr_disks + 1, sizeof (char *));
 
   remaining = info.nr_disks;
-  for (i = 0, j = 0; i < MD_MAX_DISKS && remaining > 0; i++)
+  for (i = 0, j = 0; i < GRUB_MDRAID_MAX_DISKS && remaining > 0; i++)
     {
       disk.number = i;
       ret = ioctl (fd, GET_DISK_INFO, &disk);
diff --git a/include/grub/disk.h b/include/grub/disk.h
index 071b2f7df..cbd05e9c7 100644
--- a/include/grub/disk.h
+++ b/include/grub/disk.h
@@ -172,6 +172,16 @@ typedef struct grub_disk_memberlist *grub_disk_memberlist_t;
 /* The maximum number of disk caches.  */
 #define GRUB_DISK_CACHE_NUM	1021
 
+/* The maximum number of disks in an mdraid device.
+ *
+ * GET_DISK_INFO nr_disks (total count) does not map to disk.number,
+ * which is an internal kernel index. Instead, do what mdadm does
+ * and keep scanning until we find enough valid disks. The limit is
+ * copied from there, which notes that it is sufficiently high given
+ * that the on-disk metadata for v1.x can only support 1920.
+ */
+#define GRUB_MDRAID_MAX_DISKS	4096
+
 /* The size of a disk cache in 512B units. Must be at least as big as the
    largest supported sector size, currently 16K.  */
 #define GRUB_DISK_CACHE_BITS	6
-- 
2.40.1

Re: [PATCH] Generalize MD_MAX_DISKS to GRUB_MDRAID_MAX_DISKS

[Kees Cook]

On Tue, Jun 13, 2023 at 02:54:48PM +0200, Julian Andres Klode wrote:
> Move the constant from getroot.c to disk.h and then reuse
> it place of the hardcoded 1024 limit in diskfilter.
> 
> Fixes: 2a5e3c1f2 (disk/diskfilter: Don't make a RAID array with more than 1024 disks)
> Cc: Daniel Axtens <dja@axtens.net>
> Cc: Kees Cook <keescook@chromium.org>

Yup, looks good to me. Thanks!

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  grub-core/disk/diskfilter.c     |  4 ++--
>  grub-core/osdep/linux/getroot.c | 12 ++----------
>  include/grub/disk.h             | 10 ++++++++++
>  3 files changed, 14 insertions(+), 12 deletions(-)
> 
> diff --git a/grub-core/disk/diskfilter.c b/grub-core/disk/diskfilter.c
> index 1c568927b..61a311efd 100644
> --- a/grub-core/disk/diskfilter.c
> +++ b/grub-core/disk/diskfilter.c
> @@ -1046,8 +1046,8 @@ grub_diskfilter_make_raid (grub_size_t uuidlen, char *uuid, int nmemb,
>    struct grub_diskfilter_pv *pv;
>    grub_err_t err;
>  
> -  /* We choose not to support more than 1024 disks. */
> -  if (nmemb < 1 || nmemb > 1024)
> +  /* We choose not to support more than the specified number of disks. */
> +  if (nmemb < 1 || nmemb > GRUB_MDRAID_MAX_DISKS)
>      {
>        grub_free (uuid);
>        return NULL;
> diff --git a/grub-core/osdep/linux/getroot.c b/grub-core/osdep/linux/getroot.c
> index 9cf037ec2..7dd775d2a 100644
> --- a/grub-core/osdep/linux/getroot.c
> +++ b/grub-core/osdep/linux/getroot.c
> @@ -44,6 +44,7 @@
>  
>  #include <grub/mm.h>
>  #include <grub/misc.h>
> +#include <grub/disk.h>
>  #include <grub/emu/misc.h>
>  #include <grub/emu/hostdisk.h>
>  #include <grub/emu/getroot.h>
> @@ -130,15 +131,6 @@ struct mountinfo_entry
>    char fstype[ESCAPED_PATH_MAX + 1], device[ESCAPED_PATH_MAX + 1];
>  };
>  
> -/*
> - * GET_DISK_INFO nr_disks (total count) does not map to disk.number,
> - * which is an internal kernel index. Instead, do what mdadm does
> - * and keep scanning until we find enough valid disks. The limit is
> - * copied from there, which notes that it is sufficiently high given
> - * that the on-disk metadata for v1.x can only support 1920.
> - */
> -#define MD_MAX_DISKS       4096
> -
>  static char **
>  grub_util_raid_getmembers (const char *name, int bootable)
>  {
> @@ -176,7 +168,7 @@ grub_util_raid_getmembers (const char *name, int bootable)
>    devicelist = xcalloc (info.nr_disks + 1, sizeof (char *));
>  
>    remaining = info.nr_disks;
> -  for (i = 0, j = 0; i < MD_MAX_DISKS && remaining > 0; i++)
> +  for (i = 0, j = 0; i < GRUB_MDRAID_MAX_DISKS && remaining > 0; i++)
>      {
>        disk.number = i;
>        ret = ioctl (fd, GET_DISK_INFO, &disk);
> diff --git a/include/grub/disk.h b/include/grub/disk.h
> index 071b2f7df..cbd05e9c7 100644
> --- a/include/grub/disk.h
> +++ b/include/grub/disk.h
> @@ -172,6 +172,16 @@ typedef struct grub_disk_memberlist *grub_disk_memberlist_t;
>  /* The maximum number of disk caches.  */
>  #define GRUB_DISK_CACHE_NUM	1021
>  
> +/* The maximum number of disks in an mdraid device.
> + *
> + * GET_DISK_INFO nr_disks (total count) does not map to disk.number,
> + * which is an internal kernel index. Instead, do what mdadm does
> + * and keep scanning until we find enough valid disks. The limit is
> + * copied from there, which notes that it is sufficiently high given
> + * that the on-disk metadata for v1.x can only support 1920.
> + */
> +#define GRUB_MDRAID_MAX_DISKS	4096
> +
>  /* The size of a disk cache in 512B units. Must be at least as big as the
>     largest supported sector size, currently 16K.  */
>  #define GRUB_DISK_CACHE_BITS	6
> -- 
> 2.40.1
> 

-- 
Kees Cook

Re: [PATCH] Generalize MD_MAX_DISKS to GRUB_MDRAID_MAX_DISKS

[Daniel Kiper]

On Tue, Jun 13, 2023 at 12:33:36PM -0700, Kees Cook wrote:
> On Tue, Jun 13, 2023 at 02:54:48PM +0200, Julian Andres Klode wrote:
> > Move the constant from getroot.c to disk.h and then reuse
> > it place of the hardcoded 1024 limit in diskfilter.
> >
> > Fixes: 2a5e3c1f2 (disk/diskfilter: Don't make a RAID array with more than 1024 disks)
> > Cc: Daniel Axtens <dja@axtens.net>
> > Cc: Kees Cook <keescook@chromium.org>
>
> Yup, looks good to me. Thanks!
>
> Reviewed-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Thank you for fixing this issue.

Daniel