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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-15 22:58:58 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-15 22:58:58 +0300 |
commit | 486088bc4689f826b80aa317b45ac9e42e8b25ee (patch) | |
tree | adf5847a6119d24da990d9e336f005c4a316e6be /Documentation/digsig.txt | |
parent | 52f6c588c77b76d548201470c2a28263a41b462b (diff) | |
parent | 43e5f7e1fa66531777c49791014c3124ea9208d8 (diff) | |
download | linux-486088bc4689f826b80aa317b45ac9e42e8b25ee.tar.xz |
Merge tag 'standardize-docs' of git://git.lwn.net/linux
Pull documentation format standardization from Jonathan Corbet:
"This series converts a number of top-level documents to the RST format
without incorporating them into the Sphinx tree. The hope is to bring
some uniformity to kernel documentation and, perhaps more importantly,
have our existing docs serve as an example of the desired formatting
for those that will be added later.
Mauro has gone through and fixed up a lot of top-level documentation
files to make them conform to the RST format, but without moving or
renaming them in any way. This will help when we incorporate the ones
we want to keep into the Sphinx doctree, but the real purpose is to
bring a bit of uniformity to our documentation and let the top-level
docs serve as examples for those writing new ones"
* tag 'standardize-docs' of git://git.lwn.net/linux: (84 commits)
docs: kprobes.txt: Fix whitespacing
tee.txt: standardize document format
cgroup-v2.txt: standardize document format
dell_rbu.txt: standardize document format
zorro.txt: standardize document format
xz.txt: standardize document format
xillybus.txt: standardize document format
vfio.txt: standardize document format
vfio-mediated-device.txt: standardize document format
unaligned-memory-access.txt: standardize document format
this_cpu_ops.txt: standardize document format
svga.txt: standardize document format
static-keys.txt: standardize document format
smsc_ece1099.txt: standardize document format
SM501.txt: standardize document format
siphash.txt: standardize document format
sgi-ioc4.txt: standardize document format
SAK.txt: standardize document format
rpmsg.txt: standardize document format
robust-futexes.txt: standardize document format
...
Diffstat (limited to 'Documentation/digsig.txt')
-rw-r--r-- | Documentation/digsig.txt | 131 |
1 files changed, 68 insertions, 63 deletions
diff --git a/Documentation/digsig.txt b/Documentation/digsig.txt index 3f682889068b..f6a8902d3ef7 100644 --- a/Documentation/digsig.txt +++ b/Documentation/digsig.txt @@ -1,13 +1,20 @@ +================================== Digital Signature Verification API +================================== -CONTENTS +:Author: Dmitry Kasatkin +:Date: 06.10.2011 -1. Introduction -2. API -3. User-space utilities +.. CONTENTS -1. Introduction + 1. Introduction + 2. API + 3. User-space utilities + + +Introduction +============ Digital signature verification API provides a method to verify digital signature. Currently digital signatures are used by the IMA/EVM integrity protection subsystem. @@ -17,25 +24,25 @@ GnuPG multi-precision integers (MPI) library. The kernel port provides memory allocation errors handling, has been refactored according to kernel coding style, and checkpatch.pl reported errors and warnings have been fixed. -Public key and signature consist of header and MPIs. - -struct pubkey_hdr { - uint8_t version; /* key format version */ - time_t timestamp; /* key made, always 0 for now */ - uint8_t algo; - uint8_t nmpi; - char mpi[0]; -} __packed; - -struct signature_hdr { - uint8_t version; /* signature format version */ - time_t timestamp; /* signature made */ - uint8_t algo; - uint8_t hash; - uint8_t keyid[8]; - uint8_t nmpi; - char mpi[0]; -} __packed; +Public key and signature consist of header and MPIs:: + + struct pubkey_hdr { + uint8_t version; /* key format version */ + time_t timestamp; /* key made, always 0 for now */ + uint8_t algo; + uint8_t nmpi; + char mpi[0]; + } __packed; + + struct signature_hdr { + uint8_t version; /* signature format version */ + time_t timestamp; /* signature made */ + uint8_t algo; + uint8_t hash; + uint8_t keyid[8]; + uint8_t nmpi; + char mpi[0]; + } __packed; keyid equals to SHA1[12-19] over the total key content. Signature header is used as an input to generate a signature. @@ -43,31 +50,33 @@ Such approach insures that key or signature header could not be changed. It protects timestamp from been changed and can be used for rollback protection. -2. API +API +=== -API currently includes only 1 function: +API currently includes only 1 function:: digsig_verify() - digital signature verification with public key -/** - * digsig_verify() - digital signature verification with public key - * @keyring: keyring to search key in - * @sig: digital signature - * @sigen: length of the signature - * @data: data - * @datalen: length of the data - * @return: 0 on success, -EINVAL otherwise - * - * Verifies data integrity against digital signature. - * Currently only RSA is supported. - * Normally hash of the content is used as a data for this function. - * - */ -int digsig_verify(struct key *keyring, const char *sig, int siglen, - const char *data, int datalen); - -3. User-space utilities + /** + * digsig_verify() - digital signature verification with public key + * @keyring: keyring to search key in + * @sig: digital signature + * @sigen: length of the signature + * @data: data + * @datalen: length of the data + * @return: 0 on success, -EINVAL otherwise + * + * Verifies data integrity against digital signature. + * Currently only RSA is supported. + * Normally hash of the content is used as a data for this function. + * + */ + int digsig_verify(struct key *keyring, const char *sig, int siglen, + const char *data, int datalen); + +User-space utilities +==================== The signing and key management utilities evm-utils provide functionality to generate signatures, to load keys into the kernel keyring. @@ -75,22 +84,18 @@ Keys can be in PEM or converted to the kernel format. When the key is added to the kernel keyring, the keyid defines the name of the key: 5D2B05FC633EE3E8 in the example bellow. -Here is example output of the keyctl utility. - -$ keyctl show -Session Keyring - -3 --alswrv 0 0 keyring: _ses -603976250 --alswrv 0 -1 \_ keyring: _uid.0 -817777377 --alswrv 0 0 \_ user: kmk -891974900 --alswrv 0 0 \_ encrypted: evm-key -170323636 --alswrv 0 0 \_ keyring: _module -548221616 --alswrv 0 0 \_ keyring: _ima -128198054 --alswrv 0 0 \_ keyring: _evm - -$ keyctl list 128198054 -1 key in keyring: -620789745: --alswrv 0 0 user: 5D2B05FC633EE3E8 - - -Dmitry Kasatkin -06.10.2011 +Here is example output of the keyctl utility:: + + $ keyctl show + Session Keyring + -3 --alswrv 0 0 keyring: _ses + 603976250 --alswrv 0 -1 \_ keyring: _uid.0 + 817777377 --alswrv 0 0 \_ user: kmk + 891974900 --alswrv 0 0 \_ encrypted: evm-key + 170323636 --alswrv 0 0 \_ keyring: _module + 548221616 --alswrv 0 0 \_ keyring: _ima + 128198054 --alswrv 0 0 \_ keyring: _evm + + $ keyctl list 128198054 + 1 key in keyring: + 620789745: --alswrv 0 0 user: 5D2B05FC633EE3E8 |