Hey guys,
I’m working on a project with mbedtls for the first time and need to make a file that can encrypt text using mbedtls.
I am using AES encryption with the gcm files (gcm.h and gcm.c files).
I am working on a Raspberry pi 4(the latest version with 4 cores).
Unfortunately, my code can’t compile 
I haven’t found a problem with my code but when I try to compile it gives an error message that from my understanding means that the #include I added didn’t work:
Error Msg:
/usr/bin/ld: /tmp/ccaOvpzu.o: in function
main': RoeeTestFile.c:(.text.startup+0x1c): undefined reference tombedtls_gcm_init’
/usr/bin/ld: RoeeTestFile.c:(.text.startup+0x30): undefined reference tombedtls_gcm_setkey' /usr/bin/ld: RoeeTestFile.c:(.text.startup+0x7c): undefined reference tombedtls_gcm_crypt_and_tag’
/usr/bin/ld: RoeeTestFile.c:(.text.startup+0x8c): undefined reference to `mbedtls_gcm_free’
collect2: error: ld returned 1 exit status
make: *** [: test/RoeeTestFile] Error 1
My code:
#include <stdint.h>
#include “…/crypto/include/mbedtls/cipher.h”
#if !defined(MBEDTLS_CONFIG_FILE)
#include “mbedtls/config.h”
#else
#include MBEDTLS_CONFIG_FILE
#endif
#if defined(MBEDTLS_PLATFORM_C)
#include “mbedtls/platform.h”
#else
#include <stdio.h>
#define mbedtls_printf printf
#endif
#if defined(MBEDTLS_GCM_C)
#include “mbedtls/gcm.h”
#endif
#if defined(MBEDTLS_ENTROPY_C)
#include “mbedtls/entropy.h”
#endif
#if defined(MBEDTLS_SHA256_C)
#include “mbedtls/sha256.h”
#endif
#if defined(MBEDTLS_CTR_DRBG_C)
#include “mbedtls/ctr_drbg.h”
#endif
#include <string.h>
#include “mbedtls/error.h”
#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
#include “mbedtls/memory_buffer_alloc.h”
#endif
/*
- This file will Encrypt using the “gcm.h” file
*/
#define BUFSIZE 1024
#define keySize 128
#define tagSize 200
unsigned char bufInput[BUFSIZE] = “Hello World”;
unsigned char bufOutput[BUFSIZE];
unsigned char tag[tagSize] = “BCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCD”;
int main() {
#if defined(MBEDTLS_GCM_C)
unsigned char ta[] = "123"; unsigned char* t = ta; //BufInput = "Hello World"; //tag = "BCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCDEFGHIJKLMNOPQRSTUVWXYZBCD"; //int keySize = 128; //key size /* *need to initialise key size * temp value 128 */ unsigned char key[128] = "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWX"; int ivLength = 200; unsigned char iv[ivLength]; //declaring the context struct mbedtls_gcm_context gcmContext; //initializing the gcmContext mbedtls_gcm_init(& gcmContext); //associates the gcmContext with a cipher algorithm(AES) and a key if(mbedtls_gcm_setkey(&gcmContext, MBEDTLS_CIPHER_ID_AES, key/*insert the key here */, keySize) != 0) { printf( "setkey failed :("); } if(mbedtls_gcm_crypt_and_tag(&gcmContext, MBEDTLS_GCM_ENCRYPT, BUFSIZE, iv, ivLength/*iv length */, NULL /*add - idki what this is */, 0/*add length */, bufInput, bufOutput, tagSize, tag)!= 0) { printf("Encrypting failed :("); } //clearing the gcmContext mbedtls_gcm_free(&gcmContext); //printing Original text printf("\t\tPrint Original: %s", bufInput); //printing encrypted text printf("\t\tPrint Encrypted: %s", bufOutput);#endif
#if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C)
mbedtls_memory_buffer_alloc_free();#endif
return( 0 );}
I edited a makefile that compiled other files in the same directory as my current project file.
My cMake file:
# To compile on SunOS: add "-lsocket -lnsl" to LDFLAGS
# To compile with PKCS11: add "-lpkcs11-helper" to LDFLAGS
CFLAGS ?= -O2
WARNING_CFLAGS ?= -Wall -Wextra
WARNING_CXXFLAGS ?= -Wall -Wextra
LDFLAGS ?=
LOCAL_CFLAGS = $(WARNING_CFLAGS) -I../include -D_FILE_OFFSET_BITS=64
LOCAL_CXXFLAGS = $(WARNING_CXXFLAGS) -I../include -D_FILE_OFFSET_BITS=64
LOCAL_LDFLAGS = -L../library \
-lmbedtls$(SHARED_SUFFIX) \
-lmbedx509$(SHARED_SUFFIX) \
-lmbedcrypto$(SHARED_SUFFIX)
LOCAL_LDFLAGS += -L../crypto/library
LOCAL_CFLAGS += -I../crypto/include
LOCAL_CXXFLAGS += -I../crypto/include
INCLUDING_FROM_MBEDTLS:=1
include ../crypto/3rdparty/Makefile.inc
LOCAL_CFLAGS += $(patsubst -I../3rdparty/%, -I../crypto/3rdparty/%, $(THIRDPARTY_INCLUDES))
LOCAL_CFLAGS += $(patsubst -I../3rdparty/%, -I../crypto/3rdparty/%, $(THIRDPARTY_INCLUDES))
ifdef DEBUG
LOCAL_CFLAGS += -g3
endif
# if we're running on Windows, build for Windows
ifdef WINDOWS
WINDOWS_BUILD=1
endif
ifdef WINDOWS_BUILD
DLEXT=dll
EXEXT=.exe
LOCAL_LDFLAGS += -lws2_32
ifdef SHARED
SHARED_SUFFIX=.$(DLEXT)
endif
else
DLEXT ?= so
EXEXT=
SHARED_SUFFIX=
endif
ifndef SHARED
DEP=../crypto/library/libmbedcrypto.a ../library/libmbedx509.a ../library/libmbedtls.a
else
DEP=../crypto/library/libmbedcrypto.$(DLEXT) ../library/libmbedx509.$(DLEXT) ../library/libmbedtls.$(DLEXT)
endif
# Zlib shared library extensions:
ifdef ZLIB
LOCAL_LDFLAGS += -lz
endif
APPS = \
test/RoeeTestFile$(EXEXT) \
# End of APPS
ifdef PTHREAD
APPS += ssl/ssl_pthread_server$(EXEXT)
endif
ifdef TEST_CPP
APPS += test/cpp_dummy_build$(EXEXT)
endif
.SILENT:
.PHONY: all clean list fuzz
all: $(APPS)
ifndef WINDOWS
# APPS doesn't include the fuzzing programs, which aren't "normal"
# sample or test programs, and don't build with MSVC which is
# warning about fopen
all: fuzz
endif
fuzz:
$(MAKE) -C fuzz THIRDPARTY_INCLUDES=$(THIRDPARTY_INCLUDES)
$(DEP):
$(MAKE) -C ../library
/root/mbedtls/programs/test/RoeeTestFile$(EXEXT): /root/mbedtls/programs/test/RoeeTestFile.c$(DEP)
echo " CC test/RoeeTestFile.c "
$(CC) $(LOCAL_CFLAGS) $(CFLAGS) /root/mbedtls/programs/test/RoeeTestFile.c$(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
#EXAMPLE:
#./myfile$(EXEXT): ./myfile.c $(DEP)
# echo " CC ./myfile.c"
# $(CC) $(LOCAL_CFLAGS) $(CFLAGS) ./myfile.c $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
# END OF EXAMPLE SECTION
clean:
ifndef WINDOWS
rm -f $(APPS)
-rm -f ssl/ssl_pthread_server$(EXEXT)
-rm -f test/cpp_dummy_build$(EXEXT)
else
if exist *.o del /Q /F *.o
if exist *.exe del /Q /F *.exe
endif
$(MAKE) -C fuzz clean
list:
echo $(APPS)