Re: [PATCH v2 7/8] powerpc/pseries: Read of-config partition via pstore

[Kees Cook]

On Tue, Apr 23, 2013 at 11:20 PM, Aruna Balakrishnaiah
<aruna@xxxxxxxxxxxxxxxxxx> wrote:
> This patch set exploits the pstore subsystem to read details of
> of-config partition in NVRAM to a separate file in /dev/pstore.
> For instance, of-config partition details will be stored in a
> file named [of-nvram-5].
>
> Signed-off-by: Aruna Balakrishnaiah <aruna@xxxxxxxxxxxxxxxxxx>
> Reviewed-by: Jim Keniston <jkenisto@xxxxxxxxxx>
> ---
>  arch/powerpc/platforms/pseries/nvram.c |   55 +++++++++++++++++++++++++++-----
>  fs/pstore/inode.c                      |    3 ++
>  include/linux/pstore.h                 |    1 +
>  3 files changed, 50 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
> index b118382..de448af 100644
> --- a/arch/powerpc/platforms/pseries/nvram.c
> +++ b/arch/powerpc/platforms/pseries/nvram.c
> @@ -132,9 +132,16 @@ static size_t oops_data_sz;
>  static struct z_stream_s stream;
>
>  #ifdef CONFIG_PSTORE
> +static struct nvram_os_partition of_config_partition = {
> +       .name = "of-config",
> +       .index = -1,
> +       .os_partition = false
> +};
> +
>  static enum pstore_type_id nvram_type_ids[] = {
>         PSTORE_TYPE_DMESG,
>         PSTORE_TYPE_RTAS,
> +       PSTORE_TYPE_OF,
>         -1
>  };
>  static int read_type;
> @@ -332,10 +339,15 @@ int nvram_read_partition(struct nvram_os_partition *part, char *buff,
>
>         tmp_index = part->index;
>
> -       rc = ppc_md.nvram_read((char *)&info, sizeof(struct err_log_info), &tmp_index);
> -       if (rc <= 0) {
> -               pr_err("%s: Failed nvram_read (%d)\n", __FUNCTION__, rc);
> -               return rc;
> +       if (part->os_partition) {
> +               rc = ppc_md.nvram_read((char *)&info,
> +                                       sizeof(struct err_log_info),
> +                                       &tmp_index);
> +               if (rc <= 0) {
> +                       pr_err("%s: Failed nvram_read (%d)\n", __FUNCTION__,
> +                                                                       rc);
> +                       return rc;
> +               }
>         }
>
>         rc = ppc_md.nvram_read(buff, length, &tmp_index);
> @@ -344,8 +356,10 @@ int nvram_read_partition(struct nvram_os_partition *part, char *buff,
>                 return rc;
>         }
>
> -       *error_log_cnt = info.seq_num;
> -       *err_type = info.error_type;
> +       if (part->os_partition) {
> +               *error_log_cnt = info.seq_num;
> +               *err_type = info.error_type;
> +       }
>
>         return 0;
>  }
> @@ -516,7 +530,7 @@ static int nvram_pstore_write(enum pstore_type_id type,
>  }
>
>  /*
> - * Reads the oops/panic report and ibm,rtas-log partition.
> + * Reads the oops/panic report, rtas and of-config partition.
>   * Returns the length of the data we read from each partition.
>   * Returns 0 if we've been called before.
>   */
> @@ -525,9 +539,11 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
>                                 struct pstore_info *psi)
>  {
>         struct oops_log_info *oops_hdr;
> -       unsigned int err_type, id_no;
> +       unsigned int err_type, id_no, size = 0;
>         struct nvram_os_partition *part = NULL;
>         char *buff = NULL;
> +       int sig = 0;
> +       loff_t p;
>
>         read_type++;
>
> @@ -542,10 +558,29 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
>                 time->tv_sec = last_rtas_event;
>                 time->tv_nsec = 0;
>                 break;
> +       case PSTORE_TYPE_OF:
> +               sig = NVRAM_SIG_OF;
> +               part = &of_config_partition;
> +               *type = PSTORE_TYPE_OF;
> +               *id = PSTORE_TYPE_OF;
> +               time->tv_sec = 0;
> +               time->tv_nsec = 0;
> +               break;
>         default:
>                 return 0;
>         }
>
> +       if (!part->os_partition) {
> +               p = nvram_find_partition(part->name, sig, &size);
> +               if (p <= 0) {
> +                       pr_err("nvram: Failed to find partition %s, "
> +                               "err %d\n", part->name, (int)p);
> +                       return 0;
> +               }
> +               part->index = p;
> +               part->size = size;
> +       }
> +
>         buff = kmalloc(part->size, GFP_KERNEL);
>
>         if (!buff)
> @@ -557,7 +592,9 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
>         }
>
>         *count = 0;
> -       *id = id_no;
> +
> +       if (part->os_partition)
> +               *id = id_no;
>
>         if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
>                 oops_hdr = (struct oops_log_info *)buff;
> diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
> index ec24f9c..8d4fb65 100644
> --- a/fs/pstore/inode.c
> +++ b/fs/pstore/inode.c
> @@ -327,6 +327,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
>         case PSTORE_TYPE_PPC_RTAS:
>                 sprintf(name, "rtas-%s-%lld", psname, id);
>                 break;
> +       case PSTORE_TYPE_PPC_OF:
> +               sprintf(name, "of-%s-%lld", psname, id);
> +               break;
>         case PSTORE_TYPE_UNKNOWN:
>                 sprintf(name, "unknown-%s-%lld", psname, id);
>                 break;
> diff --git a/include/linux/pstore.h b/include/linux/pstore.h
> index d7a8fe9..615dc18 100644
> --- a/include/linux/pstore.h
> +++ b/include/linux/pstore.h
> @@ -37,6 +37,7 @@ enum pstore_type_id {
>         PSTORE_TYPE_FTRACE      = 3,
>         /* PPC64 partition types */
>         PSTORE_TYPE_PPC_RTAS    = 4,
> +       PSTORE_TYPE_PPC_OF      = 5,
>         PSTORE_TYPE_UNKNOWN     = 255
>  };
>
>

Should this be named just "PSTORE_TYPE_OF" instead of "...PPC_OF"?

-Kees

--
Kees Cook
Chrome OS Security
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