Random: stricter weak entropy source checks. Remove from default options on all builds.

.github/configs/os-check-linux.json

@@ -391,7 +391,7 @@
  "user_settings": "IDE/m33mu-falcon-verify/user_settings.h",
  "configure": ["--enable-usersettings", "--disable-examples",
   "--disable-crypttests", "--disable-shared",
-  "CPPFLAGS=-DWOLFCRYPT_ONLY -DHAVE_HASHDRBG -DWC_RESEED_INTERVAL=1000000 -DWOLFSSL_NO_GETPID"],
+  "CPPFLAGS=-DWOLFCRYPT_ONLY -DHAVE_HASHDRBG -DWC_RESEED_INTERVAL=1000000 -DWOLFSSL_NO_GETPID -DWOLFSSL_ACCEPT_WEAK_ENTROPY"],
  "check": false},
 {"name": "no-server-no-client-auth", "minutes": 1.0,
  "configure": ["CPPFLAGS=-DNO_WOLFSSL_SERVER -DWOLFSSL_NO_CLIENT_AUTH"]},
@@ -598,7 +598,7 @@
  "configure": ["--enable-postauth", "--enable-sessioncerts"]},
 {"name": "leanpsk",
  "comment": "The NO_DEV_RANDOM seed path includes no system headers, so this catches an undeclared getpid() on GCC 13 too. The test-seed #warning fails -Werror and -pedantic, so extra_cflags repeats the global set minus -pedantic (and -Wno-overlength-strings, which only matters with it) and downgrades the #warning.",
- "configure": ["--enable-leanpsk"],
+ "configure": ["--enable-leanpsk", "--enable-weak-entropy"],
  "extra_cflags": "-Wdeclaration-after-statement -Wnull-dereference -DTEST_LIBWOLFSSL_SOURCES_INCLUSION_SEQUENCE -Werror=implicit-function-declaration -Wno-error=cpp",
  "check": false,
  "run": [["./wolfcrypt/test/testwolfcrypt"]]}

.github/workflows/arduino.yml

@@ -301,6 +301,13 @@ jobs:
 
           # ** END ** Install wolfSSL Arduino library
 
+      - name: Opt in to test-only Arduino entropy
+        if: matrix.fqbn != 'arduino:sam:arduino_due_x'
+        run: |
+          settings="$ARDUINO_ROOT/wolfssl/src/user_settings.h"
+          test -f "$settings"
+          sed -i '1i#define WOLFSSL_ACCEPT_WEAK_ENTROPY /* CI compile test only */' "$settings"
+
       - name: List installed Arduino libraries
         run: arduino-cli lib list
 

.github/workflows/entropy.yml

@@ -0,0 +1,32 @@
+name: Entropy Regression Tests
+
+# START OF COMMON SECTION
+on:
+  push:
+    branches: [ 'master', 'main', 'release/**' ]
+  pull_request:
+    branches: [ '*' ]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+# END OF COMMON SECTION
+
+jobs:
+  entropy:
+    if: github.repository_owner == 'wolfssl'
+    runs-on: ubuntu-24.04
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: Entropy regression tests
+        run: >-
+          python3 -m unittest
+          tests.weak_entropy_defaults
+          tests.arduino_entropy_guard
+          tests.cypress_trng_failure
+          tests.copilot_entropy_review
+          -v

.github/workflows/pic32mz-sim.yml

@@ -75,6 +75,13 @@ jobs:
       - name: Clone PIC32MZ simulator
         run: git clone --depth 1 https://github.com/wolfSSL/simulators simulators
 
+      - name: Opt in to test-only PIC32MZ entropy
+        run: |
+          cp simulators/PIC32MZSim/firmware/common/user_settings.h \
+            "$RUNNER_TEMP/pic32mz-user-settings-ci.h"
+          sed -i '1i#define WOLFSSL_ACCEPT_WEAK_ENTROPY /* simulator only */' \
+            "$RUNNER_TEMP/pic32mz-user-settings-ci.h"
+
       - uses: docker/setup-buildx-action@v4
 
       - name: Log in to ghcr (cache refresh on cron/manual dispatch)
@@ -98,5 +105,6 @@ jobs:
         run: |
           docker run --rm \
             -v "${{ github.workspace }}/wolfssl:/opt/wolfssl:ro" \
+            -v "$RUNNER_TEMP/pic32mz-user-settings-ci.h:/app/firmware/common/user_settings.h:ro" \
             ${{ matrix.image_tag }} \
             /app/scripts/${{ matrix.script }}

.github/workflows/sbom.yml

@@ -114,6 +114,7 @@ jobs:
               --user-settings-include . \
               --user-settings-include IDE/GCC-ARM/Header \
               --user-settings-define WOLFSSL_USER_SETTINGS \
+              --user-settings-define WOLFSSL_ACCEPT_WEAK_ENTROPY \
               --user-settings-define NO_STDINT_H \
               --user-settings-define WOLFSSL_NO_ASSERT_H \
               --srcs wolfcrypt/src/aes.c \
@@ -187,6 +188,8 @@ jobs:
               cdx = json.load(f)
           props = {p['name']: p['value']
                    for p in cdx['metadata']['component']['properties']}
+          assert props.get('wolfssl:security:weak-entropy') == 'permitted'
+          assert props.get('wolfssl:security:weak-entropy-note', '').startswith('WARNING:')
           assert props.get('wolfssl:sbom:hash-kind') == 'source-merkle-omnibor', \
               props
           srcs = props['wolfssl:sbom:source-set'].split(',')
@@ -255,6 +258,7 @@ jobs:
               --user-settings-include . \
               --user-settings-include IDE/GCC-ARM/Header \
               --user-settings-define WOLFSSL_USER_SETTINGS \
+              --user-settings-define WOLFSSL_ACCEPT_WEAK_ENTROPY \
               --user-settings-define NO_STDINT_H \
               --user-settings-define WOLFSSL_NO_ASSERT_H \
               --srcs wolfcrypt/src/aes.c \
@@ -283,6 +287,7 @@ jobs:
               --user-settings-include . \
               --user-settings-include IDE/GCC-ARM/Header \
               --user-settings-define WOLFSSL_USER_SETTINGS \
+              --user-settings-define WOLFSSL_ACCEPT_WEAK_ENTROPY \
               --srcs wolfcrypt/src/aes.c wolfcrypt/src/sha.c \
               --dep-libz yes \
               --dep-version libz=1.3.1 \
@@ -317,6 +322,7 @@ jobs:
           gcc -dM -E \
               -I . -I IDE/GCC-ARM/Header \
               -DWOLFSSL_USER_SETTINGS \
+              -DWOLFSSL_ACCEPT_WEAK_ENTROPY \
               -DNO_STDINT_H \
               -DWOLFSSL_NO_ASSERT_H \
               -include wolfssl/wolfcrypt/settings.h \
@@ -363,6 +369,7 @@ jobs:
               cdx = json.load(f)
           props = {p['name']: p['value']
                    for p in cdx['metadata']['component']['properties']}
+          assert props.get('wolfssl:security:weak-entropy') == 'permitted'
           build_prop_names = {
               k.split(':', 2)[-1]
               for k in props if k.startswith('wolfssl:build:')

.github/workflows/zephyr.yml

@@ -68,6 +68,12 @@ jobs:
         working-directory: zephyr
         run: west update -n -o=--depth=1
 
+      - name: Opt in to test-only QEMU entropy
+        run: |
+          settings=zephyr/modules/crypto/wolfssl/zephyr/user_settings.h
+          test -f "$settings"
+          sed -i '1i#define WOLFSSL_ACCEPT_WEAK_ENTROPY /* QEMU test only */' "$settings"
+
       - name: Export zephyr
         working-directory: zephyr
         run: west zephyr-export

IDE/AURIX/user_settings.h

@@ -71,10 +71,17 @@ extern unsigned long my_time(unsigned long* timer);
 #define HAVE_HASHDRBG
 
 /* Custom Seed Source */
+#if !defined(CUSTOM_RAND_GENERATE_SEED) && \
+    !defined(CUSTOM_RAND_GENERATE_SEED_OS) && \
+    !defined(CUSTOM_RAND_GENERATE_BLOCK) && \
+    !defined(CUSTOM_RAND_GENERATE)
+    #ifndef WOLFSSL_ACCEPT_WEAK_ENTROPY
+        #error "AURIX example counter seed is predictable: provide a secure custom seed; test only: define WOLFSSL_ACCEPT_WEAK_ENTROPY"
+    #endif
 #define CUSTOM_RAND_TYPE      unsigned int
 extern unsigned int my_rng_seed_gen(void);
-#undef  CUSTOM_RAND_GENERATE
 #define CUSTOM_RAND_GENERATE  my_rng_seed_gen
+#endif
 
 /* Standard Lib - C89 */
 #define XSTRCASECMP(s1,s2) strcmp((s1),(s2))

IDE/C2000/compile.sh

@@ -42,7 +42,7 @@ CFLAGS="-v28 --abi=eabi --float_support=fpu32 --tmu_support=tmu1 -O2 \
 # regression surface for this port, plus hash.c, which HashML-DSA
 # (wc_MlDsaKey_VerifyCtxHash) calls for the digest size and OID.
 SRCS="error wc_port memory logging misc coding hash \
-  sha sha256 sha512 sha3 wc_mldsa random ecc sp_int sp_c32 \
+  sha sha256 sha512 sha3 wc_mldsa random rng_noisesrc ecc sp_int sp_c32 \
   aes cmac chacha poly1305 cryptocb \
   curve25519 ed25519 fe_operations ge_operations \
   curve448 ed448 fe_448 ge_448"
@@ -61,25 +61,6 @@ for s in $SRCS; do
     fi
 done
 
-# rng_noisesrc.c and random.c again with the entropy gate on: that turns
-# WOLFSSL_NOISE_SRC on, compiling the generic SP800-90B noise-source layer in
-# rng_noisesrc.c and the C2000 wc_GenerateSeed() branch in random.c, both left
-# out of the sweep above.  Needs no C2000Ware - only the port .c touches
-# driverlib.
-for s in rng_noisesrc random; do
-    printf 'CC  %s.c (WOLFSSL_C2000_ENTROPY) ... ' "$s"
-    if "$CL" $CFLAGS $INCS --define=WOLFSSL_C2000_ENTROPY \
-            --compile_only --skip_assembler \
-            --asm_directory="$OUT" --obj_directory="$OUT" \
-            "$WOLFROOT/wolfcrypt/src/$s.c" > "$OUT/$s-noise.log" 2>&1; then
-        echo "ok"
-    else
-        echo "FAIL"
-        cat "$OUT/$s-noise.log"
-        rc=1
-    fi
-done
-
 # The AESA hardware-AES port needs C2000Ware driverlib headers, which CI does
 # not download, so it is an opt-in extra leg: set C2000WARE to a C2000Ware
 # install to include it.
@@ -89,7 +70,7 @@ if [ -n "${C2000WARE:-}" ]; then
         -I$C2000WARE/device_support/f28p55x/common/include \
         -I$C2000WARE/device_support/f28p55x/headers/include"
     for p in "ti-c2000-aes:--define=WOLF_CRYPTO_CB --define=WOLFSSL_C2000_AES" \
-             "ti-c2000-entropy:--define=WOLFSSL_C2000_ENTROPY"; do
+             "ti-c2000-entropy:"; do
         f=${p%%:*}
         d=${p#*:}
         printf 'CC  port/ti/%s.c ... ' "$f"

IDE/C2000/user_settings.h

@@ -40,7 +40,9 @@
 #define WOLFSSL_IGNORE_FILE_WARN
 #define BENCH_EMBEDDED
 #define NO_WOLFSSL_MEMORY
-#define WOLFSSL_GENSEED_FORTEST     /* dev-only seed; no TRNG on this part */
+/* Use the DCC oscillator-noise source for wc_GenerateSeed(). Hardware builds
+ * must also compile rng_noisesrc.c and port/ti/ti-c2000-entropy.c. */
+#define WOLFSSL_C2000_ENTROPY
 
 /* Hashes (SHA-1 is on by default - NO_SHA is not set) */
 #define WOLFSSL_SHA512

IDE/ECLIPSE/RTTHREAD/user_settings.h

@@ -33,7 +33,7 @@
 #define WOLFSSL_BENCHMARK_TEST
 #define WOLFSSL_CLIENT_TEST
 #define WOLFSSL_SERVER_TEST
-#define USE_TEST_GENSEED
+/* Supply CUSTOM_RAND_GENERATE_SEED from a hardware entropy source. */
 #define NO_DEV_RANDOM
 #define HAVE_PKCS7
 #define HAVE_AES_KEYWRAP

IDE/GCC-ARM/Header/user_settings.h

@@ -480,10 +480,16 @@ extern "C" {
 /* ------------------------------------------------------------------------- */
 
 /* Seed Source */
+#if !defined(CUSTOM_RAND_GENERATE_SEED) && \
+    !defined(CUSTOM_RAND_GENERATE_SEED_OS) && \
+    !defined(CUSTOM_RAND_GENERATE_BLOCK) && \
+    !defined(CUSTOM_RAND_GENERATE)
+    #ifndef WOLFSSL_ACCEPT_WEAK_ENTROPY
+        #error "GCC ARM example counter seed is predictable: provide a secure custom seed; test only: define WOLFSSL_ACCEPT_WEAK_ENTROPY"
+    #endif
 /* Size of returned HW RNG value */
 #define CUSTOM_RAND_TYPE      unsigned int
 extern unsigned int my_rng_seed_gen(void);
-#undef  CUSTOM_RAND_GENERATE
 #define CUSTOM_RAND_GENERATE  my_rng_seed_gen
 
 /* Choose RNG method */
@@ -501,6 +507,7 @@ extern unsigned int my_rng_seed_gen(void);
     #undef  CUSTOM_RAND_GENERATE_BLOCK
     #define CUSTOM_RAND_GENERATE_BLOCK  my_rng_gen_block
 #endif
+#endif /* no application seed source */
 
 
 /* ------------------------------------------------------------------------- */

IDE/IAR-EWARM/Projects/user_settings.h

@@ -14,7 +14,9 @@
 #define XVALIDATEDATE(d, f,t) (0)
 #define WOLFSSL_USER_CURRTIME /* for benchmark */
 
-#define WOLFSSL_GENSEED_FORTEST /* Warning: define your own seed gen */
+/* Provide a real seed source through CUSTOM_RAND_GENERATE_SEED before use.
+ * The test seed requires explicit WOLFSSL_GENSEED_FORTEST and
+ * WOLFSSL_ACCEPT_WEAK_ENTROPY definitions in the application build. */
 
 /* A few examples of different math options below.
  *

IDE/IAR-EWARM/embOS/SAMV71_XULT/embOS_SAMV71_XULT_user_settings/user_settings.h

@@ -3,6 +3,7 @@
 
     #undef WOLFSSL_EMBOS
     #define WOLFSSL_EMBOS
+    /* Supply a real seed through CUSTOM_RAND_GENERATE_SEED. */
 
     #undef WOLFCRYPT_ONLY
     #define WOLFCRYPT_ONLY

IDE/IAR-EWARM/embOS/custom_port/custom_port_user_settings/user_settings.h

@@ -3,6 +3,7 @@
 
     #undef WOLFSSL_EMBOS
     #define WOLFSSL_EMBOS
+    /* Supply a real seed through CUSTOM_RAND_GENERATE_SEED. */
 
     #undef WOLFCRYPT_ONLY
     #define WOLFCRYPT_ONLY

IDE/IAR-MSP430/user_settings.h

@@ -115,8 +115,15 @@ extern "C" {
 
 #define CUSTOM_RAND_TYPE      unsigned int
 extern unsigned int msp430_rnd(void);
-#undef  CUSTOM_RAND_GENERATE
-#define CUSTOM_RAND_GENERATE  msp430_rnd
+#if !defined(CUSTOM_RAND_GENERATE_SEED) && \
+    !defined(CUSTOM_RAND_GENERATE_SEED_OS) && \
+    !defined(CUSTOM_RAND_GENERATE_BLOCK) && \
+    !defined(CUSTOM_RAND_GENERATE)
+    #ifndef WOLFSSL_ACCEPT_WEAK_ENTROPY
+        #error "MSP430 timer XOR is not an entropy source: provide a secure custom seed; test only: define WOLFSSL_ACCEPT_WEAK_ENTROPY"
+    #endif
+    #define CUSTOM_RAND_GENERATE msp430_rnd
+#endif
 
 extern unsigned int msp430_time(long *x);
 #undef XTIME

IDE/INTIME-RTOS/user_settings.h

@@ -12,6 +12,8 @@ extern "C" {
 /* ------------------------------------------------------------------------- */
 #undef  INTIME_RTOS
 #define INTIME_RTOS
+/* INtime v6+ uses arc4random() for seeding. Older releases must provide a
+ * custom seed source; random.c rejects their clock-seeded rand() fallback. */
 
 #undef  WOLF_EXAMPLES_STACK
 #define WOLF_EXAMPLES_STACK         (1<<17)

IDE/MDK5-ARM/Conf/user_settings.h

@@ -361,15 +361,18 @@
 //  </h>
 
 //      <e>Random Seed, for TEST Only
-#define MDK_CONF_RNDSEED 1
+#define MDK_CONF_RNDSEED 0
 #if MDK_CONF_RNDSEED == 1
+#ifndef WOLFSSL_ACCEPT_WEAK_ENTROPY
+    #error "Test seed only: define WOLFSSL_ACCEPT_WEAK_ENTROPY for development; remove both before deployment"
+#endif
 #define WOLFSSL_GENSEED_FORTEST
 #endif
 //  </e>
 
 //  <h>Hardware Crypt (See document for usage)
 //      <e>Hardware RNG
-#define MDK_CONF_STM32F2_RNG 0
+#define MDK_CONF_STM32F2_RNG 1
 #if MDK_CONF_STM32F2_RNG == 1
 #define WOLFSSL_STM32_CUBEMX
 #define STM32_RNG
@@ -386,6 +389,13 @@
 
 #endif
 //  </e>
+#if MDK_CONF_STM32F2_RNG == 0 && MDK_CONF_RNDSEED == 0 && \
+    !defined(CUSTOM_RAND_GENERATE_SEED) && \
+    !defined(CUSTOM_RAND_GENERATE_SEED_OS) && \
+    !defined(CUSTOM_RAND_GENERATE_BLOCK) && \
+    !defined(CUSTOM_RAND_GENERATE)
+    #error "Enable the STM32 hardware RNG or provide a real custom seed; test only: MDK_CONF_RNDSEED=1 and WOLFSSL_ACCEPT_WEAK_ENTROPY"
+#endif
 //      <e>Hardware Crypt
 #define MDK_CONF_STM32F2_CRYPTO 0
 #if MDK_CONF_STM32F2_CRYPTO == 1
@@ -422,6 +432,13 @@
 
 #endif
 //  </e>
+#if MDK_CONF_STM32F2_CRYPTO == 0
+#define NO_STM32_CRYPTO
+#endif
+#if MDK_CONF_STM32F2_HASH == 0
+#define NO_STM32_HASH
+#define NO_STM32_HMAC
+#endif
 // </h>
 
 //  <h>Cert/Key Storage

IDE/MPLABX16/user_settings.h

@@ -38,7 +38,8 @@ extern "C" {
     #define BENCH_EMBEDDED
     #define WC_16BIT_CPU
     #define WORD64_AVAILABLE
-    #define WOLFSSL_GENSEED_FORTEST
+    /* PIC24 has no configured seed source. Supply
+     * CUSTOM_RAND_GENERATE_SEED before using the RNG. */
 #endif
 
 /* ------------------------------------------------------------------------- */

IDE/MSVS-2019-AZSPHERE/user_settings.h

@@ -26,6 +26,7 @@
 #define CUSTOM_SERVER_CONNECTION
 
 #define WOLFSSL_AZSPHERE
+/* Supply a real seed through CUSTOM_RAND_GENERATE_SEED. */
 /* Client connects to the server with these details. */
 #ifdef CUSTOM_SERVER_CONNECTION
     #ifndef SERVER_IP

IDE/NETOS/wolfssl_netos_custom.c

@@ -69,11 +69,12 @@ unsigned char get_byte_from_pool(void)
 int my_rng_generate_seed(unsigned char* output, int sz)
 {
     int i;
-    srand(get_byte_from_pool());
 
+    /* Use the pool bytes directly: the pool is the entropy source, and a
+     * libc PRNG stage would add nothing while risking entropy loss through
+     * non-random low-order bits. */
     for (i = 0; i < sz; i++) {
-        output[i] = (unsigned char) rand();
-        srand(get_byte_from_pool());
+        output[i] = get_byte_from_pool();
     }
 
     return 0;