Merge pull request #9844 from douzzer/20260226-linuxkm-SUPPORT_DUMP_TO_FILE

20260226-linuxkm-SUPPORT_DUMP_TO_FILE

Author: dgarske

.wolfssl_known_macro_extras

@@ -637,6 +637,7 @@ WC_DILITHIUM_FIXED_ARRAY
 WC_DISABLE_RADIX_ZERO_PAD
 WC_FLAG_DONT_USE_AESNI
 WC_FORCE_LINUXKM_FORTIFY_SOURCE
+WC_LINUXKM_SUPPORT_DUMP_TO_FILE
 WC_LMS_FULL_HASH
 WC_NO_ASYNC_SLEEP
 WC_NO_RNG_SIMPLE

Makefile.am

@@ -229,7 +229,7 @@ if BUILD_LINUXKM
         FIPS_FLAVOR
 
 module:
-	+$(MAKE) -C linuxkm libwolfssl.ko
+	+$(MAKE) -C linuxkm module
 
 module-update-fips-hash:
 	+$(MAKE) -C linuxkm module-update-fips-hash

linuxkm/Makefile

@@ -33,6 +33,8 @@ ifndef LIBWOLFSSL_NAME
     LIBWOLFSSL_NAME := libwolfssl
 endif
 
+module: $(LIBWOLFSSL_NAME).ko
+
 all: $(LIBWOLFSSL_NAME).ko $(LIBWOLFSSL_NAME).ko.signed
 
 ifndef MODULE_TOP
@@ -249,6 +251,7 @@ $(LIBWOLFSSL_NAME).ko:
 	echo 'CPPFLAGS = "$(CPPFLAGS)"';
 	echo 'AM_CFLAGS = "$(AM_CFLAGS)"';
 	echo 'CFLAGS = "$(CFLAGS)"';
+	echo 'HOSTCFLAGS = "$(HOSTCFLAGS)"';
 	echo 'KERNEL_EXTRA_CFLAGS = "$(KERNEL_EXTRA_CFLAGS)"';
 	echo 'FIPS_OPTEST = "$(FIPS_OPTEST)"';
 	echo 'AM_CCASFLAGS = "$(AM_CCASFLAGS)"';
@@ -261,6 +264,7 @@ $(LIBWOLFSSL_NAME).ko:
 	echo 'host_triplet = "$(host_triplet)"';
 	echo 'build_triplet = "$(build_triplet)"';
 	echo 'CC = "$(CC)"';
+	echo 'HOSTCC = "$(HOSTCC)"';
 	echo 'AS = "$(AS)"';
 	echo 'LD = "$(LD)"';
 	echo 'READELF = "$(READELF)"';
@@ -302,21 +306,25 @@ ifeq "$(ENABLED_LINUXKM_PIE)" "yes"
 	@RELOC_TMP=$$(mktemp "$(MAKE_TMPDIR)/wc_linuxkm_pie_reloc_tab.c.XXXXXX")
 	@trap 'rm "$$RELOC_TMP"' EXIT
 	@if [[ -f "$@" ]]; then touch -r "$@" "$$RELOC_TMP"; fi
-	+$(MAKE) ARCH='$(KERNEL_ARCH)' $(OVERRIDE_PATHS) $(CROSS_COMPILE) -C '$(KERNEL_ROOT)' M='$(MODULE_TOP)' $(KBUILD_EXTRA_FLAGS) CC_FLAGS_FTRACE=
+	# --no-silent works around make bug that otherwise leads to "No rule to make target 's'.  Stop." (due to a bug around $(MAKEFLAGS)) in --quiet builds.
+	+$(MAKE) $(QFLAG) --no-print-directory --no-silent ARCH='$(KERNEL_ARCH)' $(OVERRIDE_PATHS) $(CROSS_COMPILE) -C '$(KERNEL_ROOT)' M='$(MODULE_TOP)' $(KBUILD_EXTRA_FLAGS) CC_FLAGS_FTRACE=
 	# if the above make didn't build a fresh libwolfssl.ko, then the module is already up to date and we leave it untouched, assuring stability for purposes of module-update-fips-hash.
 	@if [[ ! "$@" -nt "$$RELOC_TMP" ]]; then echo '  Module already up-to-date.'; exit 0; fi
 	@SECTION_MAP=$$(mktemp)
 	@trap 'rm "$$RELOC_TMP" "$$SECTION_MAP"' EXIT
 	@export SECTION_MAP
 	@$(READELF) --wide --sections --symbols "$@" | $(GENERATE_SECTION_MAP)
 	@$(READELF) --wide --relocs "$@" | $(GENERATE_RELOC_TAB) >| '$(MODULE_TOP)/linuxkm/wc_linuxkm_pie_reloc_tab.c'
-	+$(MAKE) ARCH='$(KERNEL_ARCH)' $(OVERRIDE_PATHS) $(CROSS_COMPILE) -C '$(KERNEL_ROOT)' M='$(MODULE_TOP)' $(KBUILD_EXTRA_FLAGS) CC_FLAGS_FTRACE=
+	+$(MAKE) $(QFLAG) --no-print-directory --no-silent ARCH='$(KERNEL_ARCH)' $(OVERRIDE_PATHS) $(CROSS_COMPILE) -C '$(KERNEL_ROOT)' M='$(MODULE_TOP)' $(KBUILD_EXTRA_FLAGS) CC_FLAGS_FTRACE=
 	@$(READELF) --wide --relocs "$@" | $(GENERATE_RELOC_TAB) >| "$$RELOC_TMP"
 	@if diff '$(MODULE_TOP)/linuxkm/wc_linuxkm_pie_reloc_tab.c' "$$RELOC_TMP"; then echo " Relocation table is stable."; else echo "PIE failed: relocation table is unstable." 1>&2; exit 1; fi
 else
-	+$(MAKE) ARCH='$(KERNEL_ARCH)' $(OVERRIDE_PATHS) $(CROSS_COMPILE) -C '$(KERNEL_ROOT)' M='$(MODULE_TOP)' $(KBUILD_EXTRA_FLAGS)
+	# --no-silent works around make bug that otherwise leads to "No rule to make target 's'.  Stop." (due to a bug around $(MAKEFLAGS)) in --quiet builds.
+	+$(MAKE) $(QFLAG) --no-print-directory --no-silent ARCH='$(KERNEL_ARCH)' $(OVERRIDE_PATHS) $(CROSS_COMPILE) -C '$(KERNEL_ROOT)' M='$(MODULE_TOP)' $(KBUILD_EXTRA_FLAGS)
 endif
 
+$(MODULE_TOP)/$(LIBWOLFSSL_NAME).ko: $(LIBWOLFSSL_NAME).ko
+
 .PHONY: module-update-fips-hash
 module-update-fips-hash: $(LIBWOLFSSL_NAME).ko
 	@set -e
@@ -335,7 +343,7 @@ module-update-fips-hash: $(LIBWOLFSSL_NAME).ko
 	if [[ '$(FIPS_HASH)' == "$$current_verifyCore" ]]; then echo '	Supplied FIPS_HASH matches existing verifyCore -- no update needed.'; exit 0; fi; \
 	echo -n '$(FIPS_HASH)' | dd bs=1 conv=notrunc of="$<" seek=$$verifyCore_offset count=64 status=none && \
 	echo "	FIPS verifyCore updated successfully." && \
-            if [[ -f '$(LIBWOLFSSL_NAME).ko.signed' ]]; then $(MAKE) -C . '$(LIBWOLFSSL_NAME).ko.signed'; fi
+            if [[ -f '$(LIBWOLFSSL_NAME).ko.signed' ]]; then $(MAKE) $(QFLAG) --no-print-directory --no-silent -C . '$(LIBWOLFSSL_NAME).ko.signed'; fi
 
 
 # linuxkm-fips-hash implements offline (no-load) FIPS hash calculation and graft-in.
@@ -348,45 +356,61 @@ module-update-fips-hash: $(LIBWOLFSSL_NAME).ko
 # depending on changes/config in the source directory.  Also, aside from
 # FIPS_FLAVOR, inherited configuration settings in the environment are cleansed.
 
-libwolfssl-user-build/src/.libs/libwolfssl.so:
-	@set -e
-	@$(RM) -rf '$(MODULE_TOP)/libwolfssl-user-build'
-	@mkdir '$(MODULE_TOP)/libwolfssl-user-build'
+FRESH_MAKEFLAGS := $(patsubst -j%,-j %,$(filter -%,$(filter-out -- --jobserver-auth=%,$(MAKEFLAGS))))
+FRESH_ENV := env -i HOME="$$HOME" PATH="/usr/local/bin:/usr/bin:/bin:$$PATH" LANG="$${LANG-C.UTF-8}" LC_ALL="$${LC_ALL-C.UTF-8}" TERM="$${TERM-dumb}"
+
+.PHONY: $(MODULE_TOP)/libwolfssl-user-build/src/.libs/libwolfssl.so
+$(MODULE_TOP)/libwolfssl-user-build/src/.libs/libwolfssl.so: $(LIBWOLFSSL_NAME).ko
+	@set -o errexit -o pipefail
+	@if [[ '$(SRC_TOP)/configure' -nt '$@' ]]; then
+	@    echo 'Purging stale libwolfssl-user-build tree.'
+	@    $(RM) -rf '$(MODULE_TOP)/libwolfssl-user-build'
+	@fi
+	@mkdir -p '$(MODULE_TOP)/libwolfssl-user-build'
 	@cd '$(MODULE_TOP)/libwolfssl-user-build'
-	@pushd '$(SRC_TOP)' >/dev/null
-	@echo -n 'Populating tree of symlinks...'
-	@readarray -d '' -t srcfiles < <(find examples src support tests testsuite wolfcrypt wolfssl configure *.in build-aux debian rpm scripts certs doc mcapi cmake linuxkm/*.[ch] \( -name options.h -o -name user_settings\* \) -prune -o \( ! -type d \) \( -name '*.[chsSi]' -o -name configure -o -name '*.in' -o -name \*.sh -o -path support/\* -o -path build-aux/\* -o -path debian/\* -o -path rpm/\* -o -path scripts/\* -o -path certs/\* -o -path doc/\* -o -path mcapi/\* -o -path cmake/\* \) -print0)
-	@popd >/dev/null
-	@for file in "$${srcfiles[@]}"; do if [[ ! -e "$$file" ]]; then mkdir -p "$$(dirname "$$file")" && cp --no-dereference --symbolic-link --no-clobber '$(SRC_TOP)'/"$$file" "$$file"; fi; done
-	@echo ' done.'
-	@echo '__attribute__ ((visibility("default"))) extern const char coreKey[];' > user_settings.h
-	@echo > user_settings_asm.h
-	@echo -n 'Configuring libwolfssl.so...'
-	@unset WOLFSSL_CFLAGS WOLFCRYPT_PIE_FILES ASFLAGS_FPUSIMD_ENABLE ASFLAGS_FPU_DISABLE_SIMD_ENABLE src_libwolfssl_la_OBJECTS WOLFSSL_ASFLAGS AM_CFLAGS WOLFSSL_OBJ_FILES ENABLED_LINUXKM_LKCAPI_REGISTER EXTRA_LDFLAGS CC LD
-	@./configure $(QFLAG) $(VFLAG) --disable-jobserver --enable-cryptonly --enable-fips="$$FIPS_FLAVOR" CFLAGS='-DWC_SYM_RELOC_TABLES_SUPPORT -DWOLFCRYPT_FIPS_CORE_DYNAMIC_HASH_VALUE -DWOLFSSL_USER_SETTINGS -DWOLFSSL_USER_SETTINGS_ASM'
+	@if [[ ! -e '$(MODULE_TOP)/libwolfssl-user-build/configure' ]]; then
+	@    pushd '$(SRC_TOP)' >/dev/null
+	@    echo -n 'Populating tree of symlinks for user libwolfssl.so build...'
+	@    readarray -t srcfiles < <(find examples src support tests testsuite wolfcrypt wolfssl configure *.in build-aux debian rpm scripts certs doc mcapi cmake linuxkm/*.[ch] \( -name options.h -o -name user_settings\* \) -prune -o \( ! -type d \) \( -name '*.[chsSi]' -o -name configure -o -name '*.in' -o -name \*.sh -o -path support/\* -o -path build-aux/\* -o -path debian/\* -o -path rpm/\* -o -path scripts/\* -o -path certs/\* -o -path doc/\* -o -path mcapi/\* -o -path cmake/\* \) -print)
+	@    popd >/dev/null
+	@    for file in "$${srcfiles[@]}"; do if [[ ! -e "$$file" ]]; then mkdir -p "$$(dirname "$$file")" && cp --no-dereference --symbolic-link --no-clobber '$(SRC_TOP)'/"$$file" "$$file"; fi; done
+	@    echo ' done.'
+	@fi
+	@if [[ ! -f user_settings.h ]]; then
+	@    echo '__attribute__ ((visibility("default"))) extern const char coreKey[];' > user_settings.h
+	@    echo > user_settings_asm.h
+	@fi
+	@if [[ -f Makefile ]]; then
+	@    echo 'Using existing Makefile for libwolfssl.so.'
+	@else
+	@    echo -n 'Configuring user libwolfssl.so...'
+	@    $(FRESH_ENV) ./configure $(QFLAG) $(VFLAG) --disable-jobserver --enable-cryptonly --enable-fips="$$FIPS_FLAVOR" CFLAGS='-DWC_SYM_RELOC_TABLES_SUPPORT -DWOLFCRYPT_FIPS_CORE_DYNAMIC_HASH_VALUE -DWOLFSSL_USER_SETTINGS -DWOLFSSL_USER_SETTINGS_ASM' '$(if $(HOSTCC),CC=$(HOSTCC))'
+	@    echo ' done.'
+	@fi
+	@echo -n 'Building user libwolfssl.so...'
+	@$(FRESH_ENV) $(MAKE) $(QFLAG) $(FRESH_MAKEFLAGS) >/dev/null
 	@echo ' done.'
-	@echo -n 'Compiling and linking libwolfssl.so...'
-	+$(MAKE) $(QFLAG) >/dev/null
-	@echo ' done.'
-	@echo -n 'Fixing FIPS hash...'
-	@userhash=$$(wolfcrypt/test/testwolfcrypt 2>&1 | sed -n -E 's/^hash = (.+)$$/\1/p')
-	@if [[ -z "$$userhash" ]]; then echo ' FIPS hash not found!' >&2; exit 1; fi
-	@find wolfcrypt/src -name '*fips_test*o' -delete
-	+$(MAKE) $(QFLAG) EXTRA_CFLAGS=-DWOLFCRYPT_FIPS_CORE_HASH_VALUE="$$userhash"
-	@echo ' done.'
-
-linuxkm-fips-hash: libwolfssl-user-build/src/.libs/libwolfssl.so linuxkm-fips-hash.c
+	@echo -n 'Fixing FIPS hash in user libwolfssl.so...'
+	@if ! userhash=$$(wolfcrypt/test/testwolfcrypt 2>&1 | sed -n -E 's/^hash = (.+)$$/\1/p'); then
+	@    if [[ -z "$$userhash" ]]; then echo ' FIPS hash not found!' >&2; exit 1; fi
+	@    find wolfcrypt/src -name '*fips_test*o' -delete
+	@    $(FRESH_ENV) $(MAKE) $(QFLAG) $(FRESH_MAKEFLAGS) EXTRA_CFLAGS=-DWOLFCRYPT_FIPS_CORE_HASH_VALUE="$$userhash" >/dev/null
+	@    echo ' done.'
+	@else
+	@    	@echo ' already matches (no update needed).'
+	@fi
+
+linuxkm-fips-hash: $(MODULE_TOP)/libwolfssl-user-build/src/.libs/libwolfssl.so linuxkm-fips-hash.c
 	@set -e
 	@echo -n 'Compiling linuxkm-fips-hash...'
-# note direct invocation of cc -- we are compiling for the build host, not the target host.
-	@cc -Wall -Wextra -O2 -I'$(MODULE_TOP)/libwolfssl-user-build' -o linuxkm-fips-hash linuxkm/linuxkm-fips-hash.c -L '$(MODULE_TOP)/libwolfssl-user-build/src/.libs' -Wl,-rpath-link='$(MODULE_TOP)/libwolfssl-user-build/src/.libs' -Wl,-rpath='$(MODULE_TOP)/libwolfssl-user-build/src/.libs' -lwolfssl
+	@$(or $(HOSTCC),cc) $(or $(HOSTCFLAGS),-Wall -Wextra -O2) -I'$(MODULE_TOP)/libwolfssl-user-build' -o linuxkm-fips-hash linuxkm/linuxkm-fips-hash.c -L '$(MODULE_TOP)/libwolfssl-user-build/src/.libs' -Wl,-rpath-link='$(MODULE_TOP)/libwolfssl-user-build/src/.libs' -Wl,-rpath='$(MODULE_TOP)/libwolfssl-user-build/src/.libs' -lwolfssl
 	@echo ' done.'
 
 .PHONY: module-with-matching-fips-hash
 module-with-matching-fips-hash: $(LIBWOLFSSL_NAME).ko linuxkm-fips-hash
 	@set -e
 	@./linuxkm-fips-hash-wrapper.sh "$<" $(QFLAG) $(VFLAG)
-	+$(MAKE) $(QFLAG) -C . '$(LIBWOLFSSL_NAME).ko.signed'
+	+$(MAKE) $(QFLAG) --no-print-directory --no-silent -C . '$(LIBWOLFSSL_NAME).ko.signed'
 
 .PHONY: module-with-matching-fips-hash-no-sign
 module-with-matching-fips-hash-no-sign: $(LIBWOLFSSL_NAME).ko linuxkm-fips-hash
@@ -406,7 +430,9 @@ else
 			;;
 		esac
 	done < .config
-	if [[ "$${CONFIG_MODULE_SIG}" = "y" && -n "$${CONFIG_MODULE_SIG_KEY}" && \
+	if [[ "$${CONFIG_MODULE_SIG}" != "y" ]]; then
+		echo '  [skipping $@ -- CONFIG_MODULE_SIG is unset in target kernel]'
+	elif [[ -n "$${CONFIG_MODULE_SIG_KEY}" && \
 		-n "$${CONFIG_MODULE_SIG_HASH}" && ( ! -f '$(MODULE_TOP)/$@' || \
 			'$(MODULE_TOP)/$<' -nt '$(MODULE_TOP)/$@' ) ]]; then
 		CONFIG_MODULE_SIG_KEY="$${CONFIG_MODULE_SIG_KEY#\"}"
@@ -426,19 +452,22 @@ else
 		if [[ "$(quiet)" != "silent_" ]]; then
 			echo "	Module $@ signed by $${CONFIG_MODULE_SIG_KEY}."
 		fi
+	elif [[ ! -f '$(MODULE_TOP)/$@' || '$(MODULE_TOP)/$<' -nt '$(MODULE_TOP)/$@' ]]; then
+		echo 'Unable to generate $@ from $<: CONFIG_MODULE_SIG_KEY and/or CONFIG_MODULE_SIG_HASH is missing.' >&2
+		exit 1
 	fi
 endif
 
 
 .PHONY: install modules_install
 install modules_install:
-	+$(MAKE) -C $(KERNEL_ROOT) M=$(MODULE_TOP) src=$(SRC_TOP) INSTALL_MOD_DIR=wolfssl modules_install
+	+$(MAKE) $(QFLAG) --no-silent -C $(KERNEL_ROOT) M=$(MODULE_TOP) src=$(SRC_TOP) INSTALL_MOD_DIR=wolfssl modules_install
 
 .PHONY: clean
 # note, must supply $(MODULE_TOP) as the src value for clean so that Kbuild is included, else
 # the top Makefile (which is not for the kernel build) would be included here.
 clean:
-	+$(MAKE) -C $(KERNEL_ROOT) M=$(MODULE_TOP) src=$(MODULE_TOP) clean
+	+$(MAKE) $(QFLAG) --no-silent -C $(KERNEL_ROOT) M=$(MODULE_TOP) src=$(MODULE_TOP) clean
 	$(RM) -rf '$(MODULE_TOP)/linuxkm'
 	$(RM) -rf '$(MODULE_TOP)/wolfcrypt'
 	$(RM) -rf '$(MODULE_TOP)/src'

linuxkm/README.md

@@ -92,10 +92,10 @@ libwolfssl: kernel global random_bytes handlers installed.
 ```
 
 Additionally, `/proc/crypto` will advertise that the FIPS DRBG is installed at
-highest priority "-with-global-replace":
+highest priority, with "-wolfentropy" and/or "-rdseed", and "-with-global-replace":
 ```ini
 name         : stdrng
-driver       : sha2-256-drbg-nopr-wolfcrypt-fips-140-3-with-global-replace
+driver       : sha2-256-drbg-nopr-wolfentropy-wolfcrypt-fips-140-3-with-global-replace
 module       : libwolfssl
 priority     : 100000
 refcnt       : 2

linuxkm/linuxkm_memory.c

@@ -354,23 +354,23 @@ ssize_t wc_reloc_normalize_text(
 #ifdef DEBUG_LINUXKM_PIE_SUPPORT
                 if (reloc_buf >= seg_end - seg_beg) {
                     ++n_oob_r;
-                    RELOC_DEBUG_PRINTF("WARNING: normalized value is out of bounds (%s0x%lx) at index %ld, text offset 0x%x, reloc type %s, "
-                                         "dest seg .%s_wolfcrypt, offset from text to dest segment %s0x%lx, raw dest addr %s0x%lx, "
-                                         "seg span 0x%lx - 0x%lx, seg size 0x%lx, text base 0x%lx\n",
-                                         (sword64)reloc_buf < 0 ? "-" : "",
-                                         (sword64)reloc_buf < 0 ? -reloc_buf : reloc_buf,
-                                         i,
+                    RELOC_DEBUG_PRINTF("WARNING: normalized value is out of bounds (%s0x%llx) at index %lld, text offset 0x%x, reloc type %s, "
+                                         "dest seg .%s_wolfcrypt, offset from text to dest segment %s0x%llx, raw dest addr %s0x%llx, "
+                                         "seg span 0x%llx - 0x%llx, seg size 0x%llx, text base 0x%llx\n",
+                                         (long long)reloc_buf < 0 ? "-" : "",
+                                         (long long)reloc_buf < 0 ? -(long long)reloc_buf : (long long)reloc_buf,
+                                         (long long)i,
                                          next_reloc->offset,
                                          layout->name,
                                          seg_name,
                                          seg_beg < seg_map->text_start ? "-" : "+",
-                                         seg_beg < seg_map->text_start ? (word64)seg_map->text_start - seg_beg : seg_beg - (word64)seg_map->text_start,
-                                         (layout->is_signed && ((sword64)raw_dest_addr < 0)) ? "-" : "",
-                                         (layout->is_signed && ((sword64)raw_dest_addr < 0)) ? (word64)-(sword64)raw_dest_addr : raw_dest_addr,
-                                         (word64)seg_beg,
-                                         (word64)seg_end,
-                                         (word64)(seg_end - seg_beg),
-                                         (word64)seg_map->text_start);
+                                         seg_beg < seg_map->text_start ? (unsigned long long)seg_map->text_start - seg_beg : seg_beg - (unsigned long long)seg_map->text_start,
+                                         (layout->is_signed && ((long long)raw_dest_addr < 0)) ? "-" : "",
+                                         (layout->is_signed && ((long long)raw_dest_addr < 0)) ? (unsigned long long)-(long long)raw_dest_addr : raw_dest_addr,
+                                         (unsigned long long)seg_beg,
+                                         (unsigned long long)seg_end,
+                                         (unsigned long long)(seg_end - seg_beg),
+                                         (unsigned long long)seg_map->text_start);
                 }
 #endif
             }

linuxkm/linuxkm_wc_port.h

@@ -459,6 +459,7 @@
     #ifndef WC_CONTAINERIZE_THIS
         #include <linux/init.h>
         #include <linux/module.h>
+        #include <linux/moduleparam.h>
         #include <linux/delay.h>
     #endif
 
@@ -508,6 +509,10 @@
     #endif /* !WOLFCRYPT_ONLY */
 #endif /* !WC_CONTAINERIZE_THIS */
 
+    #ifdef WC_LINUXKM_SUPPORT_DUMP_TO_FILE
+        #include <linux/fs.h>
+        #include <linux/uaccess.h>
+    #endif
     #include <linux/slab.h>
     #include <linux/sched.h>
     #if __has_include(<linux/sched/task_stack.h>)

linuxkm/module_hooks.c

@@ -239,6 +239,74 @@ WC_MAYBE_UNUSED static int linuxkm_lkcapi_sysfs_deinstall_node(struct kobj_attri
     return 0;
 }
 
+#ifdef WC_LINUXKM_SUPPORT_DUMP_TO_FILE
+static ssize_t dump_to_file(const char *path, const u8 *buf, size_t buf_len)
+{
+    loff_t pos = 0;
+    struct file *fp;
+    ssize_t ret;
+    char tmp;
+
+    if (buf_len == 0) {
+        pr_info("libwolfssl: dump_to_file() called with buf_len == 0.  Not dumping.\n");
+        return 0;
+    }
+
+    WC_SANITIZE_DISABLE();
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5,8,0)
+    ret = probe_kernel_read(&tmp, buf, 1);
+    if (ret == 0)
+        ret = probe_kernel_read(&tmp, buf + buf_len - 1, 1);
+#else
+    ret = copy_from_kernel_nofault(&tmp, buf, 1);
+    if (ret == 0)
+        ret = copy_from_kernel_nofault(&tmp, buf + buf_len - 1, 1);
+#endif
+    WC_SANITIZE_ENABLE();
+    if (ret != 0) {
+        pr_err("libwolfssl: cannot safely read from buffer %px: %d\n", buf, (int)ret);
+        return ret;
+    }
+
+    fp = filp_open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+    if (IS_ERR(fp)) {
+        pr_err("libwolfssl: cannot open %s: %ld\n", path, PTR_ERR(fp));
+        return PTR_ERR(fp);
+    }
+
+    WC_SANITIZE_DISABLE();
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 9, 0)
+    /* kernel_write() exported by 7bb307e894d51 */
+    ret = kernel_write(fp, buf, buf_len, &pos);
+#else
+    ret = vfs_write(fp, buf, buf_len, &pos);
+#endif
+    WC_SANITIZE_ENABLE();
+
+    filp_close(fp, NULL);
+
+    if (ret < 0)
+        pr_err("libwolfssl: write to %s failed: %zd\n", path, ret);
+    else if ((size_t)ret != buf_len)
+        pr_warn("libwolfssl: short write to %s: %zd of %zu bytes\n", path, ret, buf_len);
+
+    return ret;
+}
+
+static char *text_dump_path;
+static char *rodata_dump_path;
+
+    /* indent these so they don't look like flush-left function calls. */
+    module_param(text_dump_path,   charp, 0444);
+    module_param(rodata_dump_path, charp, 0444);
+
+MODULE_PARM_DESC(text_dump_path,
+    "Path to dump live .wolfcrypt_text section to (e.g. /tmp/wc_text.bin)");
+MODULE_PARM_DESC(rodata_dump_path,
+    "Path to dump live .wolfcrypt_rodata section to (e.g. /tmp/wc_rodata.bin)");
+
+#endif /* WC_LINUXKM_SUPPORT_DUMP_TO_FILE */
+
 #ifdef HAVE_FIPS
     static ssize_t FIPS_rerun_self_test_handler(struct kobject *kobj, struct kobj_attribute *attr,
                                        const char *buf, size_t count);
@@ -503,6 +571,27 @@ static int wolfssl_init(void)
         return ret;
 #endif
 
+#ifdef WC_LINUXKM_SUPPORT_DUMP_TO_FILE
+
+#ifdef WC_SYM_RELOC_TABLES
+    if (text_dump_path) {
+        if (dump_to_file(text_dump_path, (u8 *)__wc_text_start, (size_t)((uintptr_t)__wc_text_end - (uintptr_t)__wc_text_start)) == 0)
+            pr_info("libwolfssl: dumped .wolfcrypt_text (%zu bytes) to %s.\n", (size_t)((uintptr_t)__wc_text_end - (uintptr_t)__wc_text_start), text_dump_path);
+    }
+    if (rodata_dump_path) {
+        if (dump_to_file(rodata_dump_path, (u8 *)__wc_rodata_start, (size_t)(__wc_rodata_end - __wc_rodata_start)) == 0)
+            pr_info("libwolfssl: dumped .wolfcrypt_rodata (%zu bytes) to %s.\n", (size_t)((uintptr_t)__wc_rodata_end - (uintptr_t)__wc_rodata_start), text_dump_path);
+    }
+#else
+    if ((text_dump_path != NULL) ||
+        (rodata_dump_path != NULL))
+    {
+        pr_info("libwolfssl: ignoring module dump path argument(s) -- module lacks WC_SYM_RELOC_TABLES.\n");
+    }
+#endif
+
+#endif /* WC_LINUXKM_SUPPORT_DUMP_TO_FILE */
+
 #ifdef WC_LINUXKM_TEST_INET_PTON
     {
         const char *src;