On Thu 2013-08-22 19:01:51, Lee, Chun-Yi wrote:
> This patch add the code for generate/verify signature of snapshot, it
> put the signature to snapshot header. This approach can support both
> on userspace hibernate and in-kernel hibernate.
>
> v2:
> - Due to loaded S4 sign key before ExitBootServices, we need forward key from
> boot kernel to resume target kernel. So this patch add a empty page in
> snapshot image, then we keep the pfn of this empty page in snapshot header.
> When system resume from hibernate, we fill new sign key to this empty page
> space after snapshot image checked pass. This mechanism let boot kernel can
> forward new sign key to resume target kernel but don't need write new
> private
> key to any other storage, e.g. swap.
>
> Cc: Matthew Garrett <mj...@srcf.ucam.org>
> Reviewed-by: Jiri Kosina <jkos...@suse.cz>
> Signed-off-by: Lee, Chun-Yi <j...@suse.com>
> ---
> kernel/power/power.h | 6 +
> kernel/power/snapshot.c | 280 +++++++++++++++++++++++++++++++++++++++++++++-
> kernel/power/swap.c | 14 +++
> kernel/power/user.c | 9 ++
> 4 files changed, 302 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/power/power.h b/kernel/power/power.h
> index 69a81d8..84e0b06 100644
> --- a/kernel/power/power.h
> +++ b/kernel/power/power.h
> @@ -3,6 +3,9 @@
> #include <linux/utsname.h>
> #include <linux/freezer.h>
>
> +/* The maximum length of snapshot signature */
> +#define SIG_LENG 512
> +
> struct swsusp_info {
> struct new_utsname uts;
> u32 version_code;
> @@ -11,6 +14,8 @@ struct swsusp_info {
> unsigned long image_pages;
> unsigned long pages;
> unsigned long size;
> + unsigned long skey_data_buf_pfn;
> + u8 signature[SIG_LENG];
> } __attribute__((aligned(PAGE_SIZE)));
SIG_LEN or SIG_LENGTH. Select one.
> +static int
> copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
> {
> struct zone *zone;
> - unsigned long pfn;
> + unsigned long pfn, dst_pfn;
...
> + tfm = crypto_alloc_shash(SNAPSHOT_HASH, 0, 0);
> + if (IS_ERR(tfm)) {
> + pr_err("IS_ERR(tfm): %ld", PTR_ERR(tfm));
> + return PTR_ERR(tfm);
> + }
> +
> + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
> + digest_size = crypto_shash_digestsize(tfm);
> + digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
Are you sure GFP_KERNEL allocation is okay at this phase of
hibernation?
Could the hashing be done at later phase, when writing the image to
disk?
>
> +void **h_buf;
helpfully named.
> + ret = verify_signature(s4_wake_key, pks);
> + if (ret) {
> + pr_err("snapshot S4 signature verification fail: %d\n", ret);
> + goto error_verify;
> + } else
> + pr_info("snapshot S4 signature verification pass!\n");
> +
> + if (pks->rsa.s)
> + mpi_free(pks->rsa.s);
> + kfree(pks);
ret = 0 and fall through?
> + return 0;
> +
> +error_verify:
> + if (pks->rsa.s)
> + mpi_free(pks->rsa.s);
> +error_mpi:
> + kfree(pks);
> + return ret;
> +}
> + ret = crypto_shash_final(desc, digest);
> + if (ret)
> + goto error_shash;
> +
> + ret = snapshot_verify_signature(digest, digest_size);
> + if (ret)
> + goto error_verify;
> +
> + kfree(h_buf);
> + kfree(digest);
> + crypto_free_shash(tfm);
> + return 0;
These four lines can be deleted.
> +
> +error_verify:
> +error_shash:
> + kfree(h_buf);
> + kfree(digest);
> +error_digest:
> + crypto_free_shash(tfm);
> + return ret;
> +}
> +
Pavel
--
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