On Tue Sep 24, 2024 at 9:27 PM EEST, Mikulas Patocka wrote: > > > On Tue, 24 Sep 2024, Jarkko Sakkinen wrote: > > > On Mon Sep 23, 2024 at 5:04 PM EEST, Mikulas Patocka wrote: > > > > > > > > > On Sun, 22 Sep 2024, luca.bocca...@gmail.com wrote: > > > > > > > From: Luca Boccassi <bl...@debian.org> > > > > > > > > If enabled, we fallback to the platform keyring if the trusted keyring > > > > doesn't have > > > > the key used to sign the roothash. But if pkcs7_verify() rejects the > > > > key for other > > > > reasons, such as usage restrictions, we do not fallback. Do so. > > > > > > > > Follow-up for 6fce1f40e95182ebbfe1ee3096b8fc0b37903269 > > > > > > > > Suggested-by: Serge Hallyn <se...@hallyn.com> > > > > Signed-off-by: Luca Boccassi <bl...@debian.org> > > > > > > Hi > > > > > > I'm not an expert in keyrings. > > > > > > I added keyring maintainers to the CC. Please review this patch and > > > Ack/Nack it. > > > > > > Mikulas > > > > > > > --- > > > > drivers/md/dm-verity-verify-sig.c | 2 +- > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > diff --git a/drivers/md/dm-verity-verify-sig.c > > > > b/drivers/md/dm-verity-verify-sig.c > > > > index d351d7d39c60..a9e2c6c0a33c 100644 > > > > --- a/drivers/md/dm-verity-verify-sig.c > > > > +++ b/drivers/md/dm-verity-verify-sig.c > > > > @@ -127,7 +127,7 @@ int verity_verify_root_hash(const void *root_hash, > > > > size_t root_hash_len, > > > > #endif > > > > VERIFYING_UNSPECIFIED_SIGNATURE, NULL, > > > > NULL); > > > > #ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG_PLATFORM_KEYRING > > > > - if (ret == -ENOKEY) > > > > + if (ret == -ENOKEY || ret == -EKEYREJECTED) > > > > ret = verify_pkcs7_signature(root_hash, root_hash_len, > > > > sig_data, > > > > sig_len, > > > > VERIFY_USE_PLATFORM_KEYRING, > > > > -- > > > > 2.39.5 > > > > > > > > I know nothing about dm-verity. What does it even do? > > > > BR, Jarkko > > dm-verity provides a read-only device with integrity checking. dm-verity > stores hash for every block on the block device and checks the hash when > reading the block. If the hash doesn't match, it can do one of these > actions (depending on configuration): > - return I/O error > - try to correct the data using forward error correction > - log the mismatch and do nothing > - restart the machine > - call panic() > > dm-verity is mostly used for the immutable system partition on Android > phones. For more info, see > Documentation/admin-guide/device-mapper/verity.rst > > The above patch changes the way that the signature of the root hash is > verified. I have no clue whether the patch can or can't subvert system > security, that's why I'd like to have some more reviews of the patch > before accepting it.
I guess someone who knows all this already should review it. Doesn't dm-verity have a maintainer? BR, Jarkko
