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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-15 22:58:58 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-15 22:58:58 +0300
commit486088bc4689f826b80aa317b45ac9e42e8b25ee (patch)
treeadf5847a6119d24da990d9e336f005c4a316e6be /Documentation/digsig.txt
parent52f6c588c77b76d548201470c2a28263a41b462b (diff)
parent43e5f7e1fa66531777c49791014c3124ea9208d8 (diff)
downloadlinux-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.txt131
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