__vfprintf_chk: symbol not found

[mramonlopez]

In a docker container running Alpine Linux, when trying to load the library from nodejs via pkcs11js (https://github.com/PeculiarVentures/pkcs11js), you get the error:

FAILED to run the application: NativeError: Error relocating /home/test/dist/pkcs11-grep11-amd64.so: __vfprintf_chk: symbol not found

Probably related to:

libxmljs/libxmljs#479 (comment)

[henghengxqc]

We use cgo in Grep11 PKCS11. cgo lets Go packages call C code. cgo introduces the symbol __vfprintf_chk into Grep11 PKCS11 shared library, it requires this symbol to be defined in C library.

However, Alpine Linux adopts musl libc instead of glibc. musl libc is a lightweight, fast, simple C library. But it has some compatibility problems. The error you saw is one of the problems. I dump all the symbols from musl libc, musl libc does not have __vfprintf_chk, which is required by cgo.

---

I wrote a simple cgo Go program main.go to make this easier to understand.

package main

// main.go

/*
#include <stdio.h>

void printint(int v) {
    printf("printint: %d\n", v);
}
*/
import "C"

func RobinTestCGO() {
    v := 42
    C.printint(C.int(v))
}

func main() {
}

Build main.go:

go build --buildmode=c-shared -o libtest.so

Then dump all the symbols of libtest.so

...
0000000000071970 T printint
                 U pthread_attr_destroy
                 U pthread_attr_getstacksize
                 U pthread_attr_init
                 U pthread_cond_broadcast
                 U pthread_cond_wait
                 U pthread_create
                 U pthread_detach
                 U pthread_mutex_lock
                 U pthread_mutex_unlock
                 U pthread_sigmask
                 U setegid
                 U setenv
                 U seteuid
                 U setgid
                 U setgroups
                 U setregid
                 U setresgid
                 U setresuid
                 U setreuid
                 U setuid
                 U sigfillset
                 U __stack_chk_fail
                 U stderr
                 U strerror
                 U unsetenv
                 U __vfprintf_chk
...

For the last line U __vfprintf_chk, libtest.so requires __vfprintf_chk should be defined externally(i.e. C library). But if you dump the musl libc on Alpine Linux, it does not have this symbol.

---

How to resolve it:

Option 1: Choose another Linux distribution instead of Alpine Linux, for example, Ubuntu. Ubuntu adopts glibc as the default C library. glibc has __vfprintf_chk symbol. https://packages.ubuntu.com/source/bionic/glibc

Option 2: Install glibc and libstdc++ on Alpine Linux. I did not test this solution, but it should resolve this issue in theory.

I feel like option 1 personally.