2012-10-26 21:43:59

by Seiji Aguchi

Subject: [PATCH v3 7/7] Add a format check for an existing variable name at erasing time

[Issue]

A format of variable name has been updated to type, id, count and ctime
to support holding multiple logs.

Format of current variable name
dump-type0-1-2-12345678

type:0
id:1
count:2
ctime:12345678

On the other hand, if an old variable name before being updated
remains, users can't erase it via /dev/pstore.

Format of old variable name
dump-type0-1-12345678

type:0
id:1
ctime:12345678

[Solution]

This patch adds a format check for the old variable name in a erase callback to make it erasable.

Signed-off-by: Seiji Aguchi <[email protected]>
---
drivers/firmware/efivars.c | 14 ++++++++++++--
1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index dd228d5..b1cd028 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -777,6 +777,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
struct efivars *efivars = psi->data;
struct efivar_entry *entry, *found = NULL;
int i;
+ unsigned int type_old, part_old;
+ unsigned long time_old;

sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
time.tv_sec);
@@ -796,8 +798,16 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
if (efi_guidcmp(entry->var.VendorGuid, vendor))
continue;
if (utf16_strncmp(entry->var.VariableName, efi_name,
- utf16_strlen(efi_name)))
- continue;
+ utf16_strlen(efi_name))) {
+ /*
+ * Check if an old format,
+ * which doesn't support holding
+ * multiple logs, remains.
+ */
+ if (sscanf(name, "dump-type%u-%u-%lu",
+ &type_old, &part_old, &time_old) != 3)
+ continue;
+ }

/* found */
found = entry;
-- 1.7.1

2012-10-29 20:24:49

by Mike Waychison

Subject: Re: [PATCH v3 7/7] Add a format check for an existing variable name at erasing time

On Fri, Oct 26, 2012 at 2:43 PM, Seiji Aguchi <[email protected]> wrote:
> [Issue]
>
> A format of variable name has been updated to type, id, count and ctime
> to support holding multiple logs.
>
> Format of current variable name
> dump-type0-1-2-12345678
>
> type:0
> id:1
> count:2
> ctime:12345678
>
> On the other hand, if an old variable name before being updated
> remains, users can't erase it via /dev/pstore.
>
> Format of old variable name
> dump-type0-1-12345678
>
> type:0
> id:1
> ctime:12345678
>
> [Solution]
>
> This patch adds a format check for the old variable name in a erase callback to make it erasable.
>
> Signed-off-by: Seiji Aguchi <[email protected]>
> ---
> drivers/firmware/efivars.c | 14 ++++++++++++--
> 1 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
> index dd228d5..b1cd028 100644
> --- a/drivers/firmware/efivars.c
> +++ b/drivers/firmware/efivars.c
> @@ -777,6 +777,8 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
> struct efivars *efivars = psi->data;
> struct efivar_entry *entry, *found = NULL;
> int i;
> + unsigned int type_old, part_old;
> + unsigned long time_old;
>
> sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
> time.tv_sec);
> @@ -796,8 +798,16 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
> if (efi_guidcmp(entry->var.VendorGuid, vendor))
> continue;
> if (utf16_strncmp(entry->var.VariableName, efi_name,
> - utf16_strlen(efi_name)))
> - continue;
> + utf16_strlen(efi_name))) {
> + /*
> + * Check if an old format,
> + * which doesn't support holding
> + * multiple logs, remains.
> + */
> + if (sscanf(name, "dump-type%u-%u-%lu",
> + &type_old, &part_old, &time_old) != 3)

This doesn't look right. This should probably mirror the sprintf() at
the top of the function using a new string, convert it to 16-bit
Unicodeand then compare it like we do for the 4-variable version above
(please ignore the fact that this driver incorrectly calls these
strings utf16 everywhere -- that needs to be fixed).

> + continue;
> + }
>
> /* found */
> found = entry;
> -- 1.7.1

2012-10-29 20:41:16

by Seiji Aguchi

Subject: RE: [PATCH v3 7/7] Add a format check for an existing variable name at erasing time

> > + utf16_strlen(efi_name))) {
> > + /*
> > + * Check if an old format,
> > + * which doesn't support holding
> > + * multiple logs, remains.
> > + */
> > + if (sscanf(name, "dump-type%u-%u-%lu",
> > + &type_old, &part_old, &time_old) !=
> > + 3)
>
> This doesn't look right. This should probably mirror the sprintf() at the top of the function using a new string, convert it to 16-bit
> Unicodeand then compare it like we do for the 4-variable version above (please ignore the fact that this driver incorrectly calls these
> strings utf16 everywhere -- that needs to be fixed).

I will fix it as well.

Seiji