OpenSSL_add_all_algorithms() isn't very suitable for library use. As a
library using OpenSSL doesn't know whether OpenSSL_add_all_algorithms()
has been called it must call it itself. As multiple independent
libraries may be using OpenSSL in a similar way
OpenSSL_add_all_algorithms() (and similar) may be called multiple times.
Every time OpenSSL_add_all_algorithms() is called it increases the
amount of memory the process uses. It's not a classic memory leak as
EVP_cleanup() will properly de-allocate all the memory however for all
practical purposes it acts as a memory leak as the heap will grow every
time a library initializes.
It would also be nice if libraries could safely make a corresponding
call to EVP_cleanup(). This could be done by ref counting the
initialization/deinitialization and only doing the actual
allocation/free once.
A small program demonstrating the problem:
#include <openssl/evp.h>
#include <stdlib.h>
int main(int argc, char *argv[]) {
int i, count;
if (argc != 2) {
fprintf(stderr, "Usage: %s <count>\n", argv[0]);
exit(EXIT_FAILURE);
}
count = atoi(argv[1]);
for (i = 0; i < count; i++) {
ERR_load_crypto_strings();
OpenSSL_add_all_algorithms();
}
EVP_cleanup();
abort();
return(0);
}
# export LD_PRELOAD=libumem.so.1
# export UMEM_DEBUG=default
# ./openssl_mem 1
zsh: IOT instruction (core dumped) ./openssl_mem 1
# ./openssl_mem 100
zsh: IOT instruction (core dumped) ./openssl_mem 100
# ./openssl_mem 10000
zsh: IOT instruction (core dumped) ./openssl_mem 10000
# ./openssl_mem 1000000
zsh: IOT instruction (core dumped) ./openssl_mem 1000000
# pmap /var/cores/openssl_mem* |grep total
total 3664K
total 4048K
total 30688K
total 2753532K
# for a in /var/cores/openssl_mem.200*; do echo "::findleaks" | mdb $a; done
findleaks: no memory leaks detected
findleaks: no memory leaks detected
findleaks: no memory leaks detected
findleaks: no memory leaks detected
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