Fail to locate symbol "EVP_MD_CTX_new" when referenced by "libcurl.so"

Question

I compiled both OpenSSL/1.1.1b and Curl/7.61.0 for Android. Both libraries are shared and they compile without issues. When running nm and readelf on the libraries I get the following outputs:

#
# Curl
#
❯ $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-nm -D libcurl.so | rg EVP_MD_CTX_
         U EVP_MD_CTX_free
         U EVP_MD_CTX_new

❯ $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-readelf -s app/src/main/jniLibs/armeabi-v7a/libcurl.so | rg EVP_MD_CTX_
    70: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_new@OPENSSL_1_1_0 (3)
    78: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_free@OPENSSL_1_1_0 (3)
  1793: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_new
  1801: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_free

#
# Crypto
#
❯ $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-nm -D libcrypto.so | rg EVP_MD_CTX_
00129e14 T EVP_MD_CTX_clear_flags
0011d080 T EVP_MD_CTX_copy
0011ceec T EVP_MD_CTX_copy_ex
0011d130 T EVP_MD_CTX_ctrl
0011cbb0 T EVP_MD_CTX_free
00129dd8 T EVP_MD_CTX_md
00129dec T EVP_MD_CTX_md_data
0011cb98 T EVP_MD_CTX_new
00129de4 T EVP_MD_CTX_pkey_ctx
0011cac0 T EVP_MD_CTX_reset
00129e04 T EVP_MD_CTX_set_flags
00129e30 T EVP_MD_CTX_set_pkey_ctx
00129dfc T EVP_MD_CTX_set_update_fn
00129e24 T EVP_MD_CTX_test_flags
00129df4 T EVP_MD_CTX_update_fn

❯ $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-readelf -s app/src/main/jniLibs/armeabi-v7a/libcrypto.so | rg EVP_MD_CTX_
   170: 0011cb98    24 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_new@@OPENSSL_1_1_0
   172: 00129de4     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_pkey_ctx@@OPENSSL_1_1_0
   174: 00129dd8    12 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_md@@OPENSSL_1_1_0
   177: 0011cbb0    40 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_free@@OPENSSL_1_1_0
   956: 00129dec     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_md_data@@OPENSSL_1_1_0
  1166: 00129e04    16 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_set_flags@@OPENSSL_1_1_0
  1168: 00129dfc     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_set_update_fn@@OPENSSL_1_1_0
  1307: 0011ceec   404 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_copy_ex@@OPENSSL_1_1_0
  1344: 0011cac0   216 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_reset@@OPENSSL_1_1_0
  2127: 00129e30    76 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_set_pkey_ctx@@OPENSSL_1_1_1
  2150: 00129e24    12 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_test_flags@@OPENSSL_1_1_0
  2159: 00129e14    16 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_clear_flags@@OPENSSL_1_1_0
  2164: 0011d130    56 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_ctrl@@OPENSSL_1_1_0
  2165: 0011d080    32 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_copy@@OPENSSL_1_1_0
  2276: 00129df4     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_update_fn@@OPENSSL_1_1_0
 11007: 0011cb98    24 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_new
 11009: 00129de4     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_pkey_ctx
 11011: 00129dd8    12 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_md
 11014: 0011cbb0    40 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_free
 11793: 00129dec     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_md_data
 12003: 00129e04    16 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_set_flags
 12005: 00129dfc     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_set_update_fn
 12144: 0011ceec   404 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_copy_ex
 12181: 0011cac0   216 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_reset
 12964: 00129e30    76 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_set_pkey_ctx
 12987: 00129e24    12 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_test_flags
 12996: 00129e14    16 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_clear_flags
 13001: 0011d130    56 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_ctrl
 13002: 0011d080    32 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_copy
 13113: 00129df4     8 FUNC    GLOBAL DEFAULT   11 EVP_MD_CTX_update_fn

#
# SSL
#
❯ $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-nm -D libssl.so | rg EVP_MD_CTX_
         U EVP_MD_CTX_copy
         U EVP_MD_CTX_copy_ex
         U EVP_MD_CTX_ctrl
         U EVP_MD_CTX_free
         U EVP_MD_CTX_md
         U EVP_MD_CTX_new
         U EVP_MD_CTX_set_flags

❯ $NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64/bin/arm-linux-androideabi-readelf -s libssl.so | rg EVP_MD_CTX_
   115: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_md@OPENSSL_1_1_0 (6)
   124: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_copy@OPENSSL_1_1_0 (6)
   125: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_copy_ex@OPENSSL_1_1_0 (6)
   127: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_free@OPENSSL_1_1_0 (6)
   129: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_new@OPENSSL_1_1_0 (6)
   140: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_set_flags@OPENSSL_1_1_0 (6)
   168: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_ctrl@OPENSSL_1_1_0 (6)
  2413: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_md
  2422: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_copy
  2423: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_copy_ex
  2425: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_free
  2427: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_new
  2438: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_set_flags
  2466: 00000000     0 FUNC    GLOBAL DEFAULT  UND EVP_MD_CTX_ctrl

When I try to load the libraries on android with the following code,

System.loadLibrary("crypto");
System.loadLibrary("ssl");
System.loadLibrary("curl");

I get the following error:

E/art: dlopen("/data/app/com.example.lhahn.loadlibtest-1/lib/arm/libcurl.so", RTLD_LAZY) failed: dlopen failed: cannot locate symbol "EVP_MD_CTX_new" referenced by "libcurl.so"...
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.lhahn.loadlibtest, PID: 3925
    java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "EVP_MD_CTX_new" referenced by "libcurl.so"...
        at java.lang.Runtime.loadLibrary(Runtime.java:371)
        at java.lang.System.loadLibrary(System.java:989)
        at com.example.lhahn.loadlibtest.MainActivity.onCreate(MainActivity.java:15)
        at android.app.Activity.performCreate(Activity.java:6289)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2758)
        at android.app.ActivityThread.access$900(ActivityThread.java:177)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1448)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:145)
        at android.app.ActivityThread.main(ActivityThread.java:5942)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1400)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)
I/Process: Sending signal. PID: 3925 SIG: 9
Application terminated.

However, as you can see from the output of the commands, the symbol EVP_MD_CTX_new is defined correctly (it seems so at least). The question now becomes, do you have any idea of what the problem might be? One thing that I do not understand is the symbol EVP_MD_CTX_new@OPENSSL_1_1_0 (3). I have no ideia what the suffix @OPENSSL_1_1_0 (3) means.

Some things to note is that when compiling the OpenSSL lib statically with libcurl.so the loadLibrary call works correctly. Another thing is that I am compiling the OpenSSL library with the following call to make:

make SHLIB_VERSION_NUMBER= SHLIB_EXT=.so install

This is necessary in order for libcrypto.so and libssl.so to not receive a suffix version number. Maybe this could be an issue?

Are you sure you're loading your own libcrypto and libssl copies, and not those available in `/system/lib`? See .e.g https://stackoverflow.com/questions/28341215/changing-openssl-library-in-android-app-for-httpclient — Michael, Mar 12 '19 at 16:45
The easiest solution might just be to link libcrypto and libssl statically, unless there's some good reason why you don't want to do that(?). — Michael, Mar 12 '19 at 16:46
hm, I didn't know there were already ssl and crypto libraries in /system/lib, I will check that out — lhahn, Mar 12 '19 at 16:59
I want to link dynamically to save space, since there are more libraries that use openssl — lhahn, Mar 12 '19 at 16:59
@Michael it seems that I would have to wrap the OpenSSL library into another library that exposes the OpenSSL symbols with a different name, that is correct? If that is the case I cannot do that, since that would involve in changing the source code of curl and all other libraries as well. — lhahn, Mar 12 '19 at 17:04
That seems to be the suggested approach, yeah. I've never attempted that myself, as I've only used static linking for OpenSSL. — Michael, Mar 12 '19 at 17:06
@Michael would changing the name of the library work? Maybe changing to lissl_2.so and libcrypto_2.so — lhahn, Mar 12 '19 at 18:21

Fail to locate symbol "EVP_MD_CTX_new" when referenced by "libcurl.so"

0 Answers0