SP 800-90B verdict preservation & APT/RCT compliance fixes

doc/dox_comments/header_files/random.h

@@ -113,6 +113,8 @@ int  wc_FreeNetRandom(void);
     MAX_REQUEST_LEN
     \return DRBG_CONT_FIPS_E wc_RNG_GenerateBlock: Hash_gen returned
     DRBG_CONT_FAILURE
+    \return ENTROPY_RT_E or ENTROPY_APT_E wc_InitRng: the SP 800-90B seed
+    health test rejected the entropy gathered to instantiate
     \return RNG_FAILURE_E wc_RNG_GenerateBlock: Default error.  rng’s
     status originally not ok, or set to DRBG_FAILED
     \return BAD_MUTEX_E the lock that lets threads share this rng could not
@@ -157,6 +159,8 @@ int  wc_InitRng(WC_RNG* rng);
     \return 0 on success
     \return BAD_FUNC_ARG an input is null or sz exceeds MAX_REQUEST_LEN
     \return DRBG_CONT_FIPS_E Hash_gen returned DRBG_CONT_FAILURE
+    \return ENTROPY_RT_E or ENTROPY_APT_E the SP 800-90B seed health test
+    rejected the entropy gathered for a reseed
     \return RNG_FAILURE_E Default error. rng’s status originally not
     ok, or set to DRBG_FAILED
     \return BAD_MUTEX_E the rng's lock could not be taken
@@ -544,7 +548,6 @@ int wc_RNG_DRBG_Reseed(WC_RNG* rng, const byte* seed, word32 seedSz);
     \return BAD_FUNC_ARG If seed is NULL
     \return ENTROPY_RT_E || ENTROPY_APT_E  Validation failed
     \return ENTROPY_APT_E The adaptive proportion test failed.
-    \return MEMORY_E Allocation failed.
 
     \param seed Seed to test
     \param seedSz Seed size
@@ -1009,6 +1012,9 @@ int wc_RNG_DRBG_ScheduleReseed(WC_RNG* rng);
     \return DRBG_CONT_FIPS_E The continuous test failed; the DRBG is out of
     service.
     \return RNG_FAILURE_E The DRBG is out of service or reseeding failed.
+    \return ENTROPY_RT_E or ENTROPY_APT_E The SP 800-90B seed health test
+    rejected the gathered seed; the reseed did not happen and the instance
+    remains usable until its reseed interval is reached.
 
     \param rng The RNG object to reseed.
     \param nonce Optional additional input.
@@ -1303,7 +1309,8 @@ int wc_RNG_DRBG_GetNextSeedRBGCStratum(const WC_RNG* rng);
 
     \return 0 Bytes were banked (bank may or may not yet be complete).
     \return ALREADY_E The bank is ready or being consumed.
-    \return NOT_READY_E The health test could not run; simply retry.
+    \return ENTROPY_RT_E or ENTROPY_APT_E The SP 800-90B seed health test
+    rejected the banked material, which is burned.
     \return BAD_FUNC_ARG rng is null or n is 0.
     \return MISSING_RNG_E rng has no DRBG (RDRAND et al.).
 
@@ -1334,7 +1341,8 @@ int wc_RNG_DRBG_NextSeedGenerate(WC_RNG* rng, word32 n);
 
     \return 0 Bytes were banked.
     \return ALREADY_E The bank is ready or being consumed.
-    \return NOT_READY_E The health test could not run; simply retry.
+    \return ENTROPY_RT_E or ENTROPY_APT_E The SP 800-90B seed health test
+    rejected the banked material, which is burned.
     \return BAD_FUNC_ARG rng or root is null, or n is 0.
     \return MISSING_RNG_E rng has no DRBG (RDRAND et al.).
     \return SEQ_OVERFLOW_E root's stratum is at the representable maximum.
@@ -1388,6 +1396,8 @@ int wc_RNG_DRBG_NextSeedCurrent(WC_RNG* rng, WC_ATOMIC_INT_ARG* n);
     \return NOT_READY_E No bank is ready.
     \return BAD_FUNC_ARG rng is null.
     \return MISSING_RNG_E rng has no DRBG (RDRAND et al.).
+    \return ENTROPY_RT_E or ENTROPY_APT_E A seed health test failed on
+    the reseed this performs; the instance is condemned.
 
     \param rng The RNG object to reseed.
 
@@ -1417,6 +1427,8 @@ int wc_RNG_DRBG_NextSeedNow(WC_RNG* rng);
     \return NOT_READY_E No bank is ready.
     \return BAD_FUNC_ARG rng is null, or nonce is null with nonceSz nonzero.
     \return MISSING_RNG_E rng has no DRBG (RDRAND et al.).
+    \return ENTROPY_RT_E or ENTROPY_APT_E A seed health test failed on
+    the reseed this performs; the instance is condemned.
     \return DRBG_CONT_FIPS_E The continuous test failed; the DRBG is out of
     service.
     \return RNG_FAILURE_E The DRBG is out of service.

doc/dox_comments/header_files/rng_bank.h

@@ -402,7 +402,8 @@ int wc_rng_bank_get_inst_id(struct wc_rng_bank_inst *rng_inst);
 
     \return 0 Bytes were banked.
     \return ALREADY_E The instance's bank is ready or being consumed.
-    \return NOT_READY_E The health test could not run; simply retry.
+    \return ENTROPY_RT_E or ENTROPY_APT_E The SP 800-90B seed health test
+    rejected the banked material, which is burned.
     \return BAD_FUNC_ARG bank is null, inst_offset is out of range, or n
     is 0.
 
@@ -437,7 +438,8 @@ int wc_rng_bank_next_seed_generate(struct wc_rng_bank *bank, int inst_offset,
 
     \return 0 Bytes were banked.
     \return ALREADY_E The instance's bank is ready or being consumed.
-    \return NOT_READY_E The health test could not run; simply retry.
+    \return ENTROPY_RT_E or ENTROPY_APT_E The SP 800-90B seed health test
+    rejected the banked material, which is burned.
     \return BAD_FUNC_ARG bank or root is null, inst_offset is out of range,
     or n is 0.
 

linuxkm/lkcapi_sha_glue.c

@@ -2747,10 +2747,6 @@ static void wc_linuxkm_vmgenid_poll_teardown(
  * draining nextSeeds as fast as it can.  Per-turn classification of
  * wc_rng_bank_next_seed_generate() returns:
  *   0        gathered/published -- progress;
- *   NOT_READY_E  transient (incl. a burned bank, which is refill-eligible
- *            now, and an environmental TestSeed miss with the aperture
- *            preserved) -- progress, so a forced burn can never induce
- *            a nap;
  *   ALREADY_E  ready or consuming -- no work on this instance;
  *   BUSY_E   instance-op gate held by a reinit -- no progress here,
  *            but the gate holder is making it;
@@ -3219,7 +3215,7 @@ static int wc_linuxkm_entropy_daemon(void *arg)
 
             ret = wc_rng_bank_next_seed_generate(
                 bank, i, WC_LINUXKM_ENTROPY_DAEMON_GRANULE);
-            if ((ret == 0) || (ret == WC_NO_ERR_TRACE(NOT_READY_E))) {
+            if (ret == 0) {
                 progress = 1;
             }
             else if ((ret == WC_NO_ERR_TRACE(ALREADY_E)) ||
@@ -3729,6 +3725,16 @@ WC_MAYBE_UNUSED static int linuxkm_InitRng_DefaultRef(WC_RNG* rng) {
     #define WC_LINUXKM_DRBG_SMALL_LIMIT 8
 #endif
 
+/* Reinstantiations attempted when a generate keeps failing.  Each one gathers
+ * a fresh seed and health tests it, so this never re-judges rejected data. */
+#ifndef WC_LINUXKM_DRBG_REINIT_TRIES
+    #define WC_LINUXKM_DRBG_REINIT_TRIES 3
+#endif
+/* Zero would silently turn off recovery rather than bounding it. */
+#if WC_LINUXKM_DRBG_REINIT_TRIES < 1
+    #error WC_LINUXKM_DRBG_REINIT_TRIES must be at least 1
+#endif
+
 #ifdef WC_RNG_HAVE_POOL
 wc_static_assert(WC_LINUXKM_DRBG_SMALL_LIMIT <= WC_LINUXKM_RNG_POOL_SIZE);
 #endif
@@ -3956,13 +3962,18 @@ static int wc_linuxkm_drbg_generate(struct wc_rng_bank *ctx,
         if (ret == 0)
             continue;
 
-        if (unlikely(ret == WC_NO_ERR_TRACE(RNG_FAILURE_E))) {
+        /* A seed health-test alarm now arrives as its own SP 800-90B code;
+         * it is the same recoverable condition as RNG_FAILURE_E. */
+        if (unlikely((ret == WC_NO_ERR_TRACE(RNG_FAILURE_E)) ||
+                     (ret == WC_NO_ERR_TRACE(ENTROPY_RT_E)) ||
+                     (ret == WC_NO_ERR_TRACE(ENTROPY_APT_E))))
+        {
             if (slen > 0)
                 break;
 
-            if (retried)
+            if (retried >= WC_LINUXKM_DRBG_REINIT_TRIES)
                 break;
-            retried = 1;
+            ++retried;
 
             if (! can_wait)
                 break;
@@ -4035,13 +4046,13 @@ static int wc_linuxkm_drbg_generate(struct wc_rng_bank *ctx,
 
             if (ret == 0) {
                 pr_warn_ratelimited("WARNING: reinitialized DRBG #%d after "
-                                    "RNG_FAILURE_E from wc_RNG_GenerateBlock().\n",
+                                    "a seed health or RNG failure from wc_RNG_GenerateBlock().\n",
                                     wc_rng_bank_get_inst_id(drbg));
                 continue;
             }
             else {
                 pr_err_ratelimited("ERROR: reinitialization of DRBG #%d after "
-                                   "RNG_FAILURE_E failed with ret %d.\n",
+                                   "a seed health or RNG failure failed with ret %d.\n",
                                    wc_rng_bank_get_inst_id(drbg), ret);
                 break;
             }