[PATCH] luks2: Add support for LUKS2 in (proc)/luks_script

[PATCH] luks2: Add support for LUKS2 in (proc)/luks_script

[Glenn Washburn]

The sector size in bytes is added to each line and it is allowed to be 5
decimal digits long, which covers the most common cases of 512 and 4096
byte sectors with space for an additional digit as future-proofing. The
size allocation is updated to reflect this additional field, allow up to
5 characters and 1 space added.

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 grub-core/disk/cryptodisk.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
index 34b67a705f..f2c8c8d3fe 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -1478,12 +1478,22 @@ luks_script_get (grub_size_t *sz)
   *sz = 0;
 
   for (i = cryptodisk_list; i != NULL; i = i->next)
-    if (grub_strcmp (i->modname, "luks") == 0)
+    if (grub_strcmp (i->modname, "luks") == 0 ||
+	grub_strcmp (i->modname, "luks2") == 0)
       {
-	size += sizeof ("luks_mount ");
+	size += grub_strlen (i->modname);
+	size += sizeof ("_mount");
 	size += grub_strlen (i->uuid);
 	size += grub_strlen (i->cipher->cipher->name);
-	size += 54;
+	/*
+	 * Add space in the line for (in order) spaces, cipher mode, cipher IV
+	 * mode, sector offset, sector size and the trailing newline. This is
+	 * an upper bound on the size of this data. There are 16 extra bytes
+	 * in an earlier version of this code that are unaccounted for. It is
+	 * left in the calculations in case it is needed. At worst, its short-
+	 * lived wasted space.
+	 */
+	size += 5 + 5 + 8 + 20 + 5 + 1 + 16;
 	if (i->essiv_hash)
 	  size += grub_strlen (i->essiv_hash->name);
 	size += i->keysize * 2;
@@ -1496,16 +1506,18 @@ luks_script_get (grub_size_t *sz)
   ptr = ret;
 
   for (i = cryptodisk_list; i != NULL; i = i->next)
-    if (grub_strcmp (i->modname, "luks") == 0)
+    if (grub_strcmp (i->modname, "luks") == 0 ||
+	grub_strcmp (i->modname, "luks2") == 0)
       {
 	unsigned j;
 	const char *iptr;
-	ptr = grub_stpcpy (ptr, "luks_mount ");
+	ptr = grub_stpcpy (ptr, i->modname);
+	ptr = grub_stpcpy (ptr, "_mount ");
 	ptr = grub_stpcpy (ptr, i->uuid);
 	*ptr++ = ' ';
-	grub_snprintf (ptr, 21, "%" PRIuGRUB_UINT64_T " ", i->offset_sectors);
-	while (*ptr)
-	  ptr++;
+	ptr += grub_snprintf (ptr, 21, "%" PRIuGRUB_UINT64_T " ",
+			      i->offset_sectors);
+	ptr += grub_snprintf (ptr, 7, "%d ", 1 << i->log_sector_size);
 	for (iptr = i->cipher->cipher->name; *iptr; iptr++)
 	  *ptr++ = grub_tolower (*iptr);
 	switch (i->mode)
-- 
2.34.1

Re: [PATCH] luks2: Add support for LUKS2 in (proc)/luks_script

[Daniel Kiper]

On Sun, Feb 05, 2023 at 01:05:31AM -0600, Glenn Washburn wrote:
> The sector size in bytes is added to each line and it is allowed to be 5
> decimal digits long, which covers the most common cases of 512 and 4096
> byte sectors with space for an additional digit as future-proofing. The
> size allocation is updated to reflect this additional field, allow up to
> 5 characters and 1 space added.
>
> Signed-off-by: Glenn Washburn <development@efficientek.com>
> ---
>  grub-core/disk/cryptodisk.c | 28 ++++++++++++++++++++--------
>  1 file changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
> index 34b67a705f..f2c8c8d3fe 100644
> --- a/grub-core/disk/cryptodisk.c
> +++ b/grub-core/disk/cryptodisk.c
> @@ -1478,12 +1478,22 @@ luks_script_get (grub_size_t *sz)
>    *sz = 0;
>
>    for (i = cryptodisk_list; i != NULL; i = i->next)
> -    if (grub_strcmp (i->modname, "luks") == 0)
> +    if (grub_strcmp (i->modname, "luks") == 0 ||
> +	grub_strcmp (i->modname, "luks2") == 0)
>        {
> -	size += sizeof ("luks_mount ");
> +	size += grub_strlen (i->modname);
> +	size += sizeof ("_mount");
>  	size += grub_strlen (i->uuid);
>  	size += grub_strlen (i->cipher->cipher->name);
> -	size += 54;
> +	/*
> +	 * Add space in the line for (in order) spaces, cipher mode, cipher IV
> +	 * mode, sector offset, sector size and the trailing newline. This is
> +	 * an upper bound on the size of this data. There are 16 extra bytes
> +	 * in an earlier version of this code that are unaccounted for. It is
> +	 * left in the calculations in case it is needed. At worst, its short-
> +	 * lived wasted space.
> +	 */
> +	size += 5 + 5 + 8 + 20 + 5 + 1 + 16;
>  	if (i->essiv_hash)
>  	  size += grub_strlen (i->essiv_hash->name);
>  	size += i->keysize * 2;
> @@ -1496,16 +1506,18 @@ luks_script_get (grub_size_t *sz)
>    ptr = ret;
>
>    for (i = cryptodisk_list; i != NULL; i = i->next)
> -    if (grub_strcmp (i->modname, "luks") == 0)
> +    if (grub_strcmp (i->modname, "luks") == 0 ||
> +	grub_strcmp (i->modname, "luks2") == 0)
>        {
>  	unsigned j;
>  	const char *iptr;
> -	ptr = grub_stpcpy (ptr, "luks_mount ");
> +	ptr = grub_stpcpy (ptr, i->modname);
> +	ptr = grub_stpcpy (ptr, "_mount ");
>  	ptr = grub_stpcpy (ptr, i->uuid);
>  	*ptr++ = ' ';
> -	grub_snprintf (ptr, 21, "%" PRIuGRUB_UINT64_T " ", i->offset_sectors);
> -	while (*ptr)
> -	  ptr++;
> +	ptr += grub_snprintf (ptr, 21, "%" PRIuGRUB_UINT64_T " ",
> +			      i->offset_sectors);

You, OK not you :-), blindly assume offset_sectors is 64-bit long. Today
it is but in the future it may not. May I ask you to define PRIuGRUB_DISK_ADDR,
etc. properly and fix the problem here and in the other places if needed?

> +	ptr += grub_snprintf (ptr, 7, "%d ", 1 << i->log_sector_size);

Ugh... Simple "grep -Ir log_sector_size include" revealed we use
different types in different places for log_sector_size. The most
worrying for me are include/grub/disk.h and include/grub/cryptodisk.h.
OK, probably it is not big problem here but I would prefer if we
are consistent all over the place. I think it would be good to do
"typedef grub_uint32_t grub_disk_secs_t" and use grub_disk_secs_t
consistently everywhere. Could you do that? Of course it can be
a separate patch set...

Daniel

Re: [PATCH] luks2: Add support for LUKS2 in (proc)/luks_script

[Glenn Washburn]

On Wed, 8 Feb 2023 19:39:19 +0100
Daniel Kiper <dkiper@net-space.pl> wrote:

> On Sun, Feb 05, 2023 at 01:05:31AM -0600, Glenn Washburn wrote:
> > The sector size in bytes is added to each line and it is allowed to be 5
> > decimal digits long, which covers the most common cases of 512 and 4096
> > byte sectors with space for an additional digit as future-proofing. The
> > size allocation is updated to reflect this additional field, allow up to
> > 5 characters and 1 space added.
> >
> > Signed-off-by: Glenn Washburn <development@efficientek.com>
> > ---
> >  grub-core/disk/cryptodisk.c | 28 ++++++++++++++++++++--------
> >  1 file changed, 20 insertions(+), 8 deletions(-)
> >
> > diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
> > index 34b67a705f..f2c8c8d3fe 100644
> > --- a/grub-core/disk/cryptodisk.c
> > +++ b/grub-core/disk/cryptodisk.c
> > @@ -1478,12 +1478,22 @@ luks_script_get (grub_size_t *sz)
> >    *sz = 0;
> >
> >    for (i = cryptodisk_list; i != NULL; i = i->next)
> > -    if (grub_strcmp (i->modname, "luks") == 0)
> > +    if (grub_strcmp (i->modname, "luks") == 0 ||
> > +	grub_strcmp (i->modname, "luks2") == 0)
> >        {
> > -	size += sizeof ("luks_mount ");
> > +	size += grub_strlen (i->modname);
> > +	size += sizeof ("_mount");
> >  	size += grub_strlen (i->uuid);
> >  	size += grub_strlen (i->cipher->cipher->name);
> > -	size += 54;
> > +	/*
> > +	 * Add space in the line for (in order) spaces, cipher mode, cipher IV
> > +	 * mode, sector offset, sector size and the trailing newline. This is
> > +	 * an upper bound on the size of this data. There are 16 extra bytes
> > +	 * in an earlier version of this code that are unaccounted for. It is
> > +	 * left in the calculations in case it is needed. At worst, its short-
> > +	 * lived wasted space.
> > +	 */
> > +	size += 5 + 5 + 8 + 20 + 5 + 1 + 16;
> >  	if (i->essiv_hash)
> >  	  size += grub_strlen (i->essiv_hash->name);
> >  	size += i->keysize * 2;
> > @@ -1496,16 +1506,18 @@ luks_script_get (grub_size_t *sz)
> >    ptr = ret;
> >
> >    for (i = cryptodisk_list; i != NULL; i = i->next)
> > -    if (grub_strcmp (i->modname, "luks") == 0)
> > +    if (grub_strcmp (i->modname, "luks") == 0 ||
> > +	grub_strcmp (i->modname, "luks2") == 0)
> >        {
> >  	unsigned j;
> >  	const char *iptr;
> > -	ptr = grub_stpcpy (ptr, "luks_mount ");
> > +	ptr = grub_stpcpy (ptr, i->modname);
> > +	ptr = grub_stpcpy (ptr, "_mount ");
> >  	ptr = grub_stpcpy (ptr, i->uuid);
> >  	*ptr++ = ' ';
> > -	grub_snprintf (ptr, 21, "%" PRIuGRUB_UINT64_T " ", i->offset_sectors);
> > -	while (*ptr)
> > -	  ptr++;
> > +	ptr += grub_snprintf (ptr, 21, "%" PRIuGRUB_UINT64_T " ",
> > +			      i->offset_sectors);
> 
> You, OK not you :-), blindly assume offset_sectors is 64-bit long. Today
> it is but in the future it may not. May I ask you to define PRIuGRUB_DISK_ADDR,
> etc. properly and fix the problem here and in the other places if needed?

Ok, I've added this in a recent patch.

> 
> > +	ptr += grub_snprintf (ptr, 7, "%d ", 1 << i->log_sector_size);
> 
> Ugh... Simple "grep -Ir log_sector_size include" revealed we use
> different types in different places for log_sector_size. The most
> worrying for me are include/grub/disk.h and include/grub/cryptodisk.h.
> OK, probably it is not big problem here but I would prefer if we
> are consistent all over the place. I think it would be good to do
> "typedef grub_uint32_t grub_disk_secs_t" and use grub_disk_secs_t
> consistently everywhere. Could you do that? Of course it can be
> a separate patch set...

I agree consistency is a good thing. In this case, I don't see it
realistically posing any problems. Keeping in mind that what we are
talking about here is the log() base 2 of the sector size, a terabyte
sector size will have a log of 40. This fits in 6 bits. To have a log
sector size larger than 8 bits you're talking about an unbelievably
large number. And this is the sector size we're talking about here. So
we could have this be represented in an 8-bit char and not expect it to
be an issue for at least several centuries.

I'm don't quite see the point of "typedef grub_uint32_t
grub_disk_secs_t" with regards to the log sector size, unless you're
wanting it to be used in conjunction with (1 << log_sector_size). Are
you concerned with that shift overflowing the "%d"?

Glenn