[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/Documentation/digsig.txt b/src/kernel/linux/v4.14/Documentation/digsig.txt
new file mode 100644
index 0000000..f6a8902
--- /dev/null
+++ b/src/kernel/linux/v4.14/Documentation/digsig.txt
@@ -0,0 +1,101 @@
+==================================
+Digital Signature Verification API
+==================================
+
+:Author: Dmitry Kasatkin
+:Date: 06.10.2011
+
+
+.. CONTENTS
+
+ 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.
+
+Digital signature verification is implemented using cut-down kernel port of
+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;
+
+keyid equals to SHA1[12-19] over the total key content.
+Signature header is used as an input to generate a signature.
+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.
+
+API
+===
+
+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);
+
+User-space utilities
+====================
+
+The signing and key management utilities evm-utils provide functionality
+to generate signatures, to load keys into the kernel keyring.
+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