One of my co-workers eats assembly language for breakfast. He took a
look at this, whacked together a trivial test case, and handed me a
correction to the assembly code. Credit for this fix should go to
Francis Dupont, not me.
Test case:
$ cat >test.c <<EOF
#include <openssl/x509.h>
void foo(void) { X509_print(NULL, NULL); }
EOF
$ cc -g -O -fPIC -c test.c
$ cc -shared test.o -o test.so /usr/lib64/libcrypto.a
Substitute location of libcrypto.a as needed if that's not where it
lives on your 64-bit Linux system or if you want to test against a
version you're certain was compile with -fPIC support. Error message
should be something like:
/usr/lib/gcc/x86_64-pc-linux-gnu/4.4.5/../../../../x86_64-pc-linux-gnu/bin/ld:
/usr/lib64/libcrypto.a(x86_64cpuid.o): relocation R_X86_64_PC32 against symbol
`OPENSSL_cpuid_setup' can not be used when making a shared object; recompile
with -fPIC
/usr/lib/gcc/x86_64-pc-linux-gnu/4.4.5/../../../../x86_64-pc-linux-gnu/bin/ld:
final link failed: Bad value
collect2: ld returned 1 exit status
Francis tells me that the correct way to do PIC on x86_64 is
@GOTPCREL. Here's his patch:
diff -r -u bad/openssl-1.0.0b/crypto/aes/asm/aes-x86_64.pl
fixed/openssl-1.0.0b/crypto/aes/asm/aes-x86_64.pl
--- bad/openssl-1.0.0b/crypto/aes/asm/aes-x86_64.pl 2008-12-27
14:32:21.000000000 +0100
+++ fixed/openssl-1.0.0b/crypto/aes/asm/aes-x86_64.pl 2011-03-18
21:10:47.000000000 +0100
@@ -1669,7 +1669,8 @@
lea .LAES_Td(%rip),$sbox
.Lcbc_picked_te:
- mov OPENSSL_ia32cap_P(%rip),%r10d
+ mov OPENSSL_ia32cap_P\@GOTPCREL(%rip),%r10d
+ mov (%r10d),%r10d
cmp \$$speed_limit,%rdx
jb .Lcbc_slow_prologue
test \$15,%rdx
diff -r -u bad/openssl-1.0.0b/crypto/rc4/asm/rc4-x86_64.pl
fixed/openssl-1.0.0b/crypto/rc4/asm/rc4-x86_64.pl
--- bad/openssl-1.0.0b/crypto/rc4/asm/rc4-x86_64.pl 2009-04-27
21:31:04.000000000 +0200
+++ fixed/openssl-1.0.0b/crypto/rc4/asm/rc4-x86_64.pl 2011-03-18
21:22:46.000000000 +0100
@@ -276,10 +276,11 @@
mov $len,%rcx
xor %eax,%eax
xor $ido,$ido
- xor %r10,%r10
xor %r11,%r11
- mov OPENSSL_ia32cap_P(%rip),$idx#d
+ mov OPENSSL_ia32cap_P\@GOTPCREL(%rip),%r10d
+ mov (%r10d),$idx#d
+ xor %r10,%r10
bt \$20,$idx#d
jnc .Lw1stloop
bt \$30,$idx#d
@@ -346,7 +347,8 @@
.align 16
RC4_options:
lea .Lopts(%rip),%rax
- mov OPENSSL_ia32cap_P(%rip),%edx
+ mov OPENSSL_ia32cap_P\@GOTPCREL(%rip),%edx
+ mov (%edx),%edx
bt \$20,%edx
jnc .Ldone
add \$12,%rax
Only in fixed/openssl-1.0.0b/crypto/rc4/asm: x.c
Only in fixed/openssl-1.0.0b/crypto/rc4/asm: x.s
diff -r -u bad/openssl-1.0.0b/crypto/x86_64cpuid.pl
fixed/openssl-1.0.0b/crypto/x86_64cpuid.pl
--- bad/openssl-1.0.0b/crypto/x86_64cpuid.pl 2010-04-14 21:25:09.000000000
+0200
+++ fixed/openssl-1.0.0b/crypto/x86_64cpuid.pl 2011-03-18 20:46:42.000000000
+0100
@@ -14,7 +14,7 @@
print<<___;
.extern OPENSSL_cpuid_setup
.section .init
- call OPENSSL_cpuid_setup
+ call OPENSSL_cpuid_setup\@PLT
.text
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