crypto: drbg: externalize DRBG functions for LRNG

This patch allows several DRBG functions to be called by the LRNG kernel
code paths outside the drbg.c file.

CC: Torsten Duwe <duwe@lst.de>
CC: "Eric W. Biederman" <ebiederm@xmission.com>
CC: "Alexander E. Patrakov" <patrakov@gmail.com>
CC: "Ahmed S. Darwish" <darwish.07@gmail.com>
CC: "Theodore Y. Ts'o" <tytso@mit.edu>
CC: Willy Tarreau <w@1wt.eu>
CC: Matthew Garrett <mjg59@srcf.ucam.org>
CC: Vito Caputo <vcaputo@pengaru.com>
CC: Andreas Dilger <adilger.kernel@dilger.ca>
CC: Jan Kara <jack@suse.cz>
CC: Ray Strode <rstrode@redhat.com>
CC: William Jon McCann <mccann@jhu.edu>
CC: zhangjs <zachary@baishancloud.com>
CC: Andy Lutomirski <luto@kernel.org>
CC: Florian Weimer <fweimer@redhat.com>
CC: Lennart Poettering <mzxreary@0pointer.de>
CC: Nicolai Stange <nstange@suse.de>
Reviewed-by: Alexander Lobakin <alobakin@pm.me>
Tested-by: Alexander Lobakin <alobakin@pm.me>
Reviewed-by: Roman Drahtmueller <draht@schaltsekun.de>
Tested-by: Roman Drahtmüller <draht@schaltsekun.de>
Tested-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Tested-by: Neil Horman <nhorman@redhat.com>
Tested-by: Jirka Hladky <jhladky@redhat.com>
Reviewed-by: Jirka Hladky <jhladky@redhat.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>

crypto/drbg.c

@@ -114,7 +114,7 @@
  * the SHA256 / AES 256 over other ciphers. Thus, the favored
  * DRBGs are the latest entries in this array.
  */
-static const struct drbg_core drbg_cores[] = {
+const struct drbg_core drbg_cores[] = {
 #ifdef CONFIG_CRYPTO_DRBG_CTR
 	{
 		.flags = DRBG_CTR | DRBG_STRENGTH128,
@@ -191,6 +191,7 @@ static const struct drbg_core drbg_cores[] = {
 	},
 #endif /* CONFIG_CRYPTO_DRBG_HMAC */
 };
+EXPORT_SYMBOL(drbg_cores);
 
 static int drbg_uninstantiate(struct drbg_state *drbg);
 
@@ -206,7 +207,7 @@ static int drbg_uninstantiate(struct drbg_state *drbg);
  * Return: normalized strength in *bytes* value or 32 as default
  *	   to counter programming errors
  */
-static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
+unsigned short drbg_sec_strength(drbg_flag_t flags)
 {
 	switch (flags & DRBG_STRENGTH_MASK) {
 	case DRBG_STRENGTH128:
@@ -219,6 +220,7 @@ static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
 		return 32;
 	}
 }
+EXPORT_SYMBOL(drbg_sec_strength);
 
 /*
  * FIPS 140-2 continuous self test for the noise source
@@ -1215,7 +1217,7 @@ static int drbg_seed(struct drbg_state *drbg, struct drbg_string *pers,
 }
 
 /* Free all substructures in a DRBG state without the DRBG state structure */
-static inline void drbg_dealloc_state(struct drbg_state *drbg)
+void drbg_dealloc_state(struct drbg_state *drbg)
 {
 	if (!drbg)
 		return;
@@ -1236,12 +1238,13 @@ static inline void drbg_dealloc_state(struct drbg_state *drbg)
 		drbg->fips_primed = false;
 	}
 }
+EXPORT_SYMBOL(drbg_dealloc_state);
 
 /*
  * Allocate all sub-structures for a DRBG state.
  * The DRBG state structure must already be allocated.
  */
-static inline int drbg_alloc_state(struct drbg_state *drbg)
+int drbg_alloc_state(struct drbg_state *drbg)
 {
 	int ret = -ENOMEM;
 	unsigned int sb_size = 0;
@@ -1322,6 +1325,7 @@ static inline int drbg_alloc_state(struct drbg_state *drbg)
 	drbg_dealloc_state(drbg);
 	return ret;
 }
+EXPORT_SYMBOL(drbg_alloc_state);
 
 /*************************************************************************
  * DRBG interface functions
@@ -1891,8 +1895,7 @@ static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
  *
  * return: flags
  */
-static inline void drbg_convert_tfm_core(const char *cra_driver_name,
-					 int *coreref, bool *pr)
+void drbg_convert_tfm_core(const char *cra_driver_name, int *coreref, bool *pr)
 {
 	int i = 0;
 	size_t start = 0;
@@ -1919,6 +1922,7 @@ static inline void drbg_convert_tfm_core(const char *cra_driver_name,
 		}
 	}
 }
+EXPORT_SYMBOL(drbg_convert_tfm_core);
 
 static int drbg_kcapi_init(struct crypto_tfm *tfm)
 {

include/crypto/drbg.h

@@ -278,4 +278,11 @@ enum drbg_prefixes {
 	DRBG_PREFIX3
 };
 
+extern int drbg_alloc_state(struct drbg_state *drbg);
+extern void drbg_dealloc_state(struct drbg_state *drbg);
+extern void drbg_convert_tfm_core(const char *cra_driver_name, int *coreref,
+				  bool *pr);
+extern const struct drbg_core drbg_cores[];
+extern unsigned short drbg_sec_strength(drbg_flag_t flags);
+
 #endif /* _DRBG_H */