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Message-Id: <cover.1313082284.git.dmitry.kasatkin@intel.com> Date: Thu, 11 Aug 2011 20:20:03 +0300 From: Dmitry Kasatkin <dmitry.kasatkin@...el.com> To: linux-security-module@...r.kernel.org Cc: linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org, zohar@...ux.vnet.ibm.com Subject: [RFC v1.1 0/5] evm: digital signature extension Hello, As EVM patches were recently merged to security-testing-2.6#next, it is a good time to resend evm signature verification patches for active discussion. Last time I forgot --cc linux-crypto. Here it is. This patchset introduces digital signature extensions for the IMA/EVM kernel integrity subsystem and is applied on the top of the EVM patches posted to LSM mailing list earlier. Currently EVM stores the HMAC in security.evm to verify integrity of the file's metadata. This is quite sufficient for individually installed systems, where a system unique HMAC key can be provisioned and the initial filesystem labeling can be done. Software installation for consumer electronics or embedded devices is usually done via flashing a filesystem image. Initial filesystem image labeling is done during image creation process. It either has to be done (1) using a system unique HMAC key or (2) using an image specific HMAC key. In first case, those keys are either unknown, or a unique image has to be created for thousand or millions of devices, which is not feasible. The second case, using an image specific HMAC key, would require (2.1) provisioning of the key to millions of devices, which is not easily feasible or (2.1) encrypting the key with a shared symmetric key which is not a strong security measure. Digital signature extension for EVM provides a solution to perform labeling of the image using a single digital private key and use a known public key to verify the signature. For performance reasons, after verification, signature is replaced with local HMAC. Digital signature verification uses RSA algorithm, implemented using cut-down port of multi-precision integers (MPI) library from GnuPG and has been taken from RedHat Enterprise Linux kernel (MODSIGN patches). Decision to use this library was made, because its performance was 2 times better than other ports such as libtommath library. The motivation for integrity protection, in general, is to protect against offline modifications. The runtime protection is ensured via access control mechanisms. Of particular importance is protecting users or owners from being sold or given tampered devices, which can do nasty things such as spying or stealing personal data. Integrity protection ensures that modifications of the system will not remain undetected. The EVM digital signature extension makes this feasible for consumerelectronics/embedded devices. There is also a second patchset which implements digital signature support for IMA-appraisal patchset, which is planned to be reviewed right after the IMA-appaisal review. All patches on the top of ima-2.6 (3.x.x) kernel are available here: http://meego.gitorious.org/meego-platform-security/ima-ksign Supporting utility for key handling and signing is available here: http://meego.gitorious.org/meego-platform-security/evm-utils Regards, Dmitry Dmitry Kasatkin (5): crypto: GnuPG based MPI lib crypto: ksign - digital signature verification support evm: digital signature support ksign: provides keyring to search in for the key evm: creates dedicated evm keyring to store public keys crypto/Kconfig | 19 + crypto/Makefile | 4 + crypto/ksign.c | 270 +++++++ crypto/mpi/Makefile | 30 + crypto/mpi/generic_mpi-asm-defs.h | 10 + crypto/mpi/generic_mpih-add1.c | 62 ++ crypto/mpi/generic_mpih-lshift.c | 66 ++ crypto/mpi/generic_mpih-mul1.c | 58 ++ crypto/mpi/generic_mpih-mul2.c | 63 ++ crypto/mpi/generic_mpih-mul3.c | 64 ++ crypto/mpi/generic_mpih-rshift.c | 65 ++ crypto/mpi/generic_mpih-sub1.c | 62 ++ crypto/mpi/generic_udiv-w-sdiv.c | 130 +++ crypto/mpi/longlong.h | 1502 +++++++++++++++++++++++++++++++++++ crypto/mpi/mpi-add.c | 258 ++++++ crypto/mpi/mpi-bit.c | 245 ++++++ crypto/mpi/mpi-cmp.c | 71 ++ crypto/mpi/mpi-div.c | 345 ++++++++ crypto/mpi/mpi-gcd.c | 60 ++ crypto/mpi/mpi-inline.c | 33 + crypto/mpi/mpi-inline.h | 128 +++ crypto/mpi/mpi-internal.h | 265 ++++++ crypto/mpi/mpi-inv.c | 148 ++++ crypto/mpi/mpi-mpow.c | 113 +++ crypto/mpi/mpi-mul.c | 202 +++++ crypto/mpi/mpi-pow.c | 312 ++++++++ crypto/mpi/mpi-scan.c | 129 +++ crypto/mpi/mpicoder.c | 359 +++++++++ crypto/mpi/mpih-cmp.c | 58 ++ crypto/mpi/mpih-div.c | 534 +++++++++++++ crypto/mpi/mpih-mul.c | 546 +++++++++++++ crypto/mpi/mpiutil.c | 213 +++++ include/linux/crypto/ksign.h | 48 ++ include/linux/crypto/mpi.h | 147 ++++ security/integrity/evm/Kconfig | 14 + security/integrity/evm/evm.h | 33 + security/integrity/evm/evm_crypto.c | 66 ++- security/integrity/evm/evm_main.c | 83 ++- 38 files changed, 6783 insertions(+), 32 deletions(-) create mode 100644 crypto/ksign.c create mode 100644 crypto/mpi/Makefile create mode 100644 crypto/mpi/generic_mpi-asm-defs.h create mode 100644 crypto/mpi/generic_mpih-add1.c create mode 100644 crypto/mpi/generic_mpih-lshift.c create mode 100644 crypto/mpi/generic_mpih-mul1.c create mode 100644 crypto/mpi/generic_mpih-mul2.c create mode 100644 crypto/mpi/generic_mpih-mul3.c create mode 100644 crypto/mpi/generic_mpih-rshift.c create mode 100644 crypto/mpi/generic_mpih-sub1.c create mode 100644 crypto/mpi/generic_udiv-w-sdiv.c create mode 100644 crypto/mpi/longlong.h create mode 100644 crypto/mpi/mpi-add.c create mode 100644 crypto/mpi/mpi-bit.c create mode 100644 crypto/mpi/mpi-cmp.c create mode 100644 crypto/mpi/mpi-div.c create mode 100644 crypto/mpi/mpi-gcd.c create mode 100644 crypto/mpi/mpi-inline.c create mode 100644 crypto/mpi/mpi-inline.h create mode 100644 crypto/mpi/mpi-internal.h create mode 100644 crypto/mpi/mpi-inv.c create mode 100644 crypto/mpi/mpi-mpow.c create mode 100644 crypto/mpi/mpi-mul.c create mode 100644 crypto/mpi/mpi-pow.c create mode 100644 crypto/mpi/mpi-scan.c create mode 100644 crypto/mpi/mpicoder.c create mode 100644 crypto/mpi/mpih-cmp.c create mode 100644 crypto/mpi/mpih-div.c create mode 100644 crypto/mpi/mpih-mul.c create mode 100644 crypto/mpi/mpiutil.c create mode 100644 include/linux/crypto/ksign.h create mode 100644 include/linux/crypto/mpi.h -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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