Hello misc@,
I'm currently trying to write a library that heavily relies on
libcrypto. Because I don't want applications linking to it, to have to
call OpenSSL_add_all_algorithms, for convenience, I added those calls to
the appropriate places in my library. Because of this nature, the
function is called multiple times, and even if I shielded it within my
library it could still be called outside of it by an application using
my library.
On AMD64 (OpenBSD 5.5-stable) this hasn't given me any problems yet, but
as soon as I run my code on i386 (5.6-current) it crashes with the
following trace:
#0 obj_name_LHASH_COMP (arg1=0x0, arg2=0x857b7630) at
/usr/src/lib/libcrypto/crypto/../../libssl/src/crypto/objects/o_names.c:97
#1 0x0e91190c in getrn (lh=0x867d0380, data=0x857b7630, rhash=Variable
"rhash" is not available.
) at /usr/src/lib/libcrypto/crypto/../../libssl/src/crypto/lhash/lhash.c:419
#2 0x0e911c92 in lh_insert (lh=0x867d0380, data=0x857b7630) at
/usr/src/lib/libcrypto/crypto/../../libssl/src/crypto/lhash/lhash.c:192
#3 0x0e8a0852 in OBJ_NAME_add (name=0x2e800aac "aes-256-cfb", type=2,
data=0x2e815360 "\001")
at
/usr/src/lib/libcrypto/crypto/../../libssl/src/crypto/objects/o_names.c:181
#4 0x0e8a0149 in EVP_add_cipher (c=0x2e815360) at
/usr/src/lib/libcrypto/crypto/../../libssl/src/crypto/evp/names.c:80
#5 0x0e8384f3 in OpenSSL_add_all_ciphers () at
/usr/src/lib/libcrypto/crypto/../../libssl/src/crypto/evp/c_allc.c:183
#6 0x0e8357bc in OPENSSL_add_all_algorithms_noconf () at
/usr/src/lib/libcrypto/crypto/../../libssl/src/crypto/evp/c_all.c:76
I'm aware that the OpenSSL_add_all_algorithms(3) says:
A typical application will call OpenSSL_add_all_algorithms() initially
and EVP_cleanup() before exiting.
but it doesn't explicitly says that it can only be called ones without
causing problems.
Could anyone tell me if this kind of use of this function is the
undefined behaviour area that I should avoid or if this is a bug? If it
is grey area that should be avoided, what is the recommended way to
initialise ciphers and digests from within the library without risking
crashes from initialization from within an application? I do use
EVP_get_{cipher,digest}bynid(3), so all ciphers and digests need to be
available.
Sincerely,
Martijn van Duren
