Re: static linking libssl and libcrypto

[Aijaz Baig <aijazbaig1@xxxxxxxxx>]

ldd libAPP.so does NOT have any reference to libSSL.so or for that matter any SSL library. Which is why I had to use nm to check for SSL related symbols

On Mon, Nov 4, 2019 at 6:31 PM Floodeenjr, Thomas <thomas_floodeenjr@xxxxxxxxxx> wrote:

To check if you are linked statically or dynamically, what does ldd tell you? (ldd libAPP.so) Your library should not have a dependency on libssl.so or libcrypto.so if you are linked statically.

 

-Tom

 

From: openssl-users [mailto:openssl-users-bounces@xxxxxxxxxxx] On Behalf Of Aijaz Baig
Sent: Sunday, November 3, 2019 11:30 PM
To: openssl-users@xxxxxxxxxxx
Subject: static linking libssl and libcrypto

 

I am trying to build a shared library that internally links openssl and crypto libraries statically so I can use it in a production environment. To that end I am using the following Makefile

APPBASE=/home/AB/Documents/APP/APP_2.17.0

OPENSSL1.0.2p_INSTALL_LOC=/home/AB/Documents/APP/OpenSSL-1.0.2p-installation

CC=gcc

CFLAGS= -Wall -g -O -fPIC

RM= rm -f

.PHONY: all clean

src="" *Generic/*.c *Linux/*.c)

$(info source=$(src))

#we use the custom compiled openssl version

#and NOT the one available on the system

#INC=-I/usr/include/openssl

INC+=-I$(OPENSSL1.0.2p_INSTALL_LOC)/include/openssl

INC+=$(foreach d,$(incdir),-I$d)

$(info includes=$(INC))

LIB=-L$(OPENSSL1.0.2p_INSTALL_LOC)/lib

#LIB=-llibssl -llibcrypto

LIB+=-lssl -lcrypto

$(info links=$(LIB))

#LIB+=-L/usr/lib/

obj=$(src:.c=.o)

all: libAPP.so

clean:

    $(RM) *.o *.so

    $(shell find $(APPBASE) -type f -iname "*.o" -exec rm -rf {} \;)

.c.o:

    ${CC} -static ${CFLAGS} $(INC) -c $< $(LIB) -o $@

libAPP.so: $(obj)

    $(LINK.c) -shared $^ -o $@

As mentioned here (https://stackoverflow.com/questions/18185618/how-to-use-static-linking-with-openssl-in-c-c/25811538#25811538), I've changed the linker flags to:

-lcrypto -lz -ldl -static-libgcc

 

but it doesn't seem to change the size of the generated so file. On checking for references to SSL in this so file, I see there are a total of 87 entries

 

nm libAPP.so | grep -i "ssl" | wc -l

87

 

whereas listing only the global symbols from libssl.a tells me it has 1113 globally defined symbols.

nm -g ../OpenSSL-1.0.2p-installation/lib/libssl.a | grep -i "ssl" | wc -l

1113

 

I do not know if libSSL got indeed linked statically or not. Could someone please shed some light on it?

 

--

Best Regards,

Aijaz Baig

--

Best Regards,

Aijaz Baig