[v31,08/12] crypto: provide access to a static Jitter RNG state

Commit Message

Stephan Mueller July 13, 2020, 6:20 a.m. UTC

To support the LRNG operation which uses the Jitter RNG separately
from the kernel crypto API, at a time where potentially the regular
memory management is not yet initialized, the Jitter RNG needs to
provide a state whose memory is defined at compile time. As only once
instance will ever be needed by the LRNG, define once static memory
block which is solely to be used by the LRNG.

CC: "Eric W. Biederman" <[e-mail]>
CC: "Alexander E. Patrakov" <[e-mail]>
CC: "Ahmed S. Darwish" <[e-mail]>
CC: "Theodore Y. Ts'o" <[e-mail]>
CC: Willy Tarreau <[e-mail]>
CC: Matthew Garrett <[e-mail]>
CC: Vito Caputo <[e-mail]>
CC: Andreas Dilger <[e-mail]>
CC: Jan Kara <[e-mail]>
CC: Ray Strode <[e-mail]>
CC: William Jon McCann <[e-mail]>
CC: zhangjs <[e-mail]>
CC: Andy Lutomirski <[e-mail]>
CC: Florian Weimer <[e-mail]>
CC: Lennart Poettering <[e-mail]>
CC: Nicolai Stange <[e-mail]>
Reviewed-by: Roman Drahtmueller <[e-mail]>
Tested-by: Roman Drahtmüller <[e-mail]>
Tested-by: Marcelo Henrique Cerri <[e-mail]>
Tested-by: Neil Horman <[e-mail]>
Signed-off-by: Stephan Mueller <[e-mail]>
---
 crypto/jitterentropy-kcapi.c                  |  3 +-
 crypto/jitterentropy.c                        | 31 ++++++++++++++++++-
 .../crypto/internal}/jitterentropy.h          |  3 ++
 3 files changed, 34 insertions(+), 3 deletions(-)
 rename {crypto => include/crypto/internal}/jitterentropy.h (84%)

Patch

diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c
index b43684c0dade..ed21fab13da6 100644
--- a/crypto/jitterentropy-kcapi.c
+++ b/crypto/jitterentropy-kcapi.c
@@ -43,8 +43,7 @@ 
 #include <linux/time.h>
 #include <linux/crypto.h>
 #include <crypto/internal/rng.h>
-
-#include "jitterentropy.h"
+#include <crypto/internal/jitterentropy.h>
 
 /***************************************************************************
  * Helper function
diff --git a/crypto/jitterentropy.c b/crypto/jitterentropy.c
index 57f4a1ac738b..7ab229c6c96b 100644
--- a/crypto/jitterentropy.c
+++ b/crypto/jitterentropy.c
@@ -117,7 +117,7 @@  struct rand_data {
 #define JENT_EHEALTH		9 /* Health test failed during initialization */
 #define JENT_ERCT		10 /* RCT failed during initialization */
 
-#include "jitterentropy.h"
+#include <crypto/internal/jitterentropy.h>
 
 /***************************************************************************
  * Adaptive Proportion Test
@@ -854,3 +854,32 @@  int jent_entropy_init(void)
 
 	return 0;
 }
+
+struct rand_data *jent_lrng_entropy_collector(void)
+{
+	static unsigned char lrng_jent_mem[JENT_MEMORY_SIZE];
+	static struct rand_data lrng_jent_state = {
+		.data		= 0,
+		.old_data	= 0,
+		.prev_time	= 0,
+		.last_delta	= 0,
+		.last_delta2	= 0,
+		.osr		= 1,
+		.mem		= lrng_jent_mem,
+		.memlocation	= 0,
+		.memblocks	= JENT_MEMORY_BLOCKSIZE,
+		.memblocksize	= JENT_MEMORY_BLOCKS,
+		.memaccessloops	= JENT_MEMORY_ACCESSLOOPS,
+		.rct_count	= 0,
+		.apt_observations = 0,
+		.apt_count	= 0,
+		.apt_base	= 0,
+		.apt_base_set	= 0,
+		.health_failure = 0
+	};
+
+	if (jent_entropy_init())
+		return NULL;
+
+	return &lrng_jent_state;
+}
diff --git a/crypto/jitterentropy.h b/include/crypto/internal/jitterentropy.h
similarity index 84%
rename from crypto/jitterentropy.h
rename to include/crypto/internal/jitterentropy.h
index c83fff32d130..6e07d86eac82 100644
--- a/crypto/jitterentropy.h
+++ b/include/crypto/internal/jitterentropy.h
@@ -15,3 +15,6 @@  extern int jent_read_entropy(struct rand_data *ec, unsigned char *data,
 extern struct rand_data *jent_entropy_collector_alloc(unsigned int osr,
 						      unsigned int flags);
 extern void jent_entropy_collector_free(struct rand_data *entropy_collector);
+
+/* Access to statically allocated Jitter RNG instance */
+extern struct rand_data *jent_lrng_entropy_collector(void);