Messages in this thread | | | Subject | Re: [PATCH 12/18] Hibernate: generate and verify signature of snapshot | From | joeyli <> | Date | Tue, 27 Aug 2013 11:22:28 +0800 |
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Hi Pavel,
Thanks for your time to review my patches.
於 日,2013-08-25 於 18:36 +0200,Pavel Machek 提到: > 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 <mjg59@srcf.ucam.org> > > Reviewed-by: Jiri Kosina <jkosina@suse.cz> > > Signed-off-by: Lee, Chun-Yi <jlee@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. >
I will use SIG_LEN at next version, thanks!
> > > +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? >
Thanks for you point out!
Yes, call memory allocate here is not a good design due to it causes garbage in snapshot that will not released by resumed kernel.
I just finished another implementation, the respin patch extracts the signature generation code to another function then call the function in swsusp_save() after copy_data_pages() finished. We can write to memory at that stage.
> > > > +void **h_buf; > > helpfully named. >
I will change the name to handle_buffers;
> > + 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? >
When verification success, verify_signature() will return 0.
Yes, here have duplicate code, I will clear up it.
> > + 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. >
Yes, here also duplicate, I will remove.
> > + > > +error_verify: > > +error_shash: > > + kfree(h_buf); > > + kfree(digest); > > +error_digest: > > + crypto_free_shash(tfm); > > + return ret; > > +} > > + > Pavel
Thanks a lot! Joey Lee
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