Commit f21b5b64 authored by Andy Polyakov's avatar Andy Polyakov
Browse files

x509v3/v3_purp.c: re-implement lock-free check for extensions cache validity. 



Reviewed-by: default avatarPaul Dale <paul.dale@oracle.com>
Reviewed-by: default avatarRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6786)
parent 0da7358b

crypto/include/internal/x509_int.h

+1 −0
Original line number Diff line number Diff line
@@ -182,6 +182,7 @@ struct x509_st { 
    unsigned char sha1_hash[SHA_DIGEST_LENGTH];

    X509_CERT_AUX *aux;

    CRYPTO_RWLOCK *lock;

    volatile int ex_cached;

} /* X509 */ ;



/*

crypto/x509v3/v3_purp.c

+11 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <openssl/x509v3.h>

#include <openssl/x509_vfy.h>

#include "internal/x509_int.h"

#include "internal/tsan_assist.h"



static void x509v3_cache_extensions(X509 *x);
@@ -353,6 +354,10 @@ static void x509v3_cache_extensions(X509 *x) 
    X509_EXTENSION *ex;

    int i;



    /* fast lock-free check, see end of the function for details. */

    if (tsan_load((TSAN_QUALIFIER int *)&x->ex_cached))

        return;



    CRYPTO_THREAD_write_lock(x->lock);

    if (x->ex_flags & EXFLAG_SET) {

        CRYPTO_THREAD_unlock(x->lock);
@@ -494,6 +499,12 @@ static void x509v3_cache_extensions(X509 *x) 
    x509_init_sig_info(x);

    x->ex_flags |= EXFLAG_SET;

    CRYPTO_THREAD_unlock(x->lock);

    /*

     * It has to be placed after memory barrier, which is implied by unlock.

     * Worst thing that can happen is that another thread proceeds to lock

     * and checks x->ex_flags & EXFLAGS_SET. See beginning of the function.

     */

    tsan_store((TSAN_QUALIFIER int *)&x->ex_cached, 1);

}



/*-