keys: add new key-type encrypted
Define a new kernel key-type called 'encrypted'. Encrypted keys are kernel
generated random numbers, which are encrypted/decrypted with a 'trusted'
symmetric key. Encrypted keys are created/encrypted/decrypted in the kernel.
Userspace only ever sees/stores encrypted blobs.
Changelog:
- bug fix: replaced master-key rcu based locking with semaphore
(reported by David Howells)
- Removed memset of crypto_shash_digest() digest output
- Replaced verification of 'key-type:key-desc' using strcspn(), with
one based on string constants.
- Moved documentation to Documentation/keys-trusted-encrypted.txt
- Replace hash with shash (based on comments by David Howells)
- Make lengths/counts size_t where possible (based on comments by David Howells)
Could not convert most lengths, as crypto expects 'unsigned int'
(size_t: on 32 bit is defined as unsigned int, but on 64 bit is unsigned long)
- Add 'const' where possible (based on comments by David Howells)
- allocate derived_buf dynamically to support arbitrary length master key
(fixed by Roberto Sassu)
- wait until late_initcall for crypto libraries to be registered
- cleanup security/Kconfig
- Add missing 'update' keyword (reported/fixed by Roberto Sassu)
- Free epayload on failure to create key (reported/fixed by Roberto Sassu)
- Increase the data size limit (requested by Roberto Sassu)
- Crypto return codes are always 0 on success and negative on failure,
remove unnecessary tests.
- Replaced kzalloc() with kmalloc()
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: David Safford <safford@watson.ibm.com>
Reviewed-by: Roberto Sassu <roberto.sassu@polito.it>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/Kconfig b/security/Kconfig
index 24b8f9b..95accd4 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -36,6 +36,22 @@
If you are unsure as to whether this is required, answer N.
+config ENCRYPTED_KEYS
+ tristate "ENCRYPTED KEYS"
+ depends on KEYS && TRUSTED_KEYS
+ select CRYPTO_AES
+ select CRYPTO_CBC
+ select CRYPTO_SHA256
+ select CRYPTO_RNG
+ help
+ This option provides support for create/encrypting/decrypting keys
+ in the kernel. Encrypted keys are kernel generated random numbers,
+ which are encrypted/decrypted with a 'master' symmetric key. The
+ 'master' key can be either a trusted-key or user-key type.
+ Userspace only ever sees/stores encrypted blobs.
+
+ If you are unsure as to whether this is required, answer N.
+
config KEYS_DEBUG_PROC_KEYS
bool "Enable the /proc/keys file by which keys may be viewed"
depends on KEYS