crypto/x509/x509_vfy.c:879: error: NULL_DEREFERENCE
  pointer `x` last assigned on line 872 could be null and is dereferenced at line 879, column 9.
Showing all 16 steps of the trace


crypto/x509/x509_vfy.c:867:1: start of procedure check_cert()
865.   }
866.   
867. > static int check_cert(X509_STORE_CTX *ctx)
868.   {
869.       X509_CRL *crl = NULL, *dcrl = NULL;

crypto/x509/x509_vfy.c:869:5: 
867.   static int check_cert(X509_STORE_CTX *ctx)
868.   {
869. >     X509_CRL *crl = NULL, *dcrl = NULL;
870.       int ok = 0;
871.       int cnum = ctx->error_depth;

crypto/x509/x509_vfy.c:870:5: 
868.   {
869.       X509_CRL *crl = NULL, *dcrl = NULL;
870. >     int ok = 0;
871.       int cnum = ctx->error_depth;
872.       X509 *x = sk_X509_value(ctx->chain, cnum);

crypto/x509/x509_vfy.c:871:5: 
869.       X509_CRL *crl = NULL, *dcrl = NULL;
870.       int ok = 0;
871. >     int cnum = ctx->error_depth;
872.       X509 *x = sk_X509_value(ctx->chain, cnum);
873.   

crypto/x509/x509_vfy.c:872:5: 
870.       int ok = 0;
871.       int cnum = ctx->error_depth;
872. >     X509 *x = sk_X509_value(ctx->chain, cnum);
873.   
874.       ctx->current_cert = x;

include/openssl/x509.h:99:1: start of procedure sk_X509_value()
  97.   typedef struct x509_cinf_st X509_CINF;
  98.   
  99. > DEFINE_STACK_OF(X509)
  100.   
  101.   /* This is used for a table of trust checking functions */

crypto/stack/stack.c:380:1: start of procedure OPENSSL_sk_value()
    378.   }
    379.   
    380. > void *OPENSSL_sk_value(const OPENSSL_STACK *st, int i)
    381.   {
    382.       if (i < 0 || i >= st->num)

crypto/stack/stack.c:382:9: Taking true branch
    380.   void *OPENSSL_sk_value(const OPENSSL_STACK *st, int i)
    381.   {
    382.       if (i < 0 || i >= st->num)
                   ^
    383.           return NULL;
    384.       return (void *)st->data[i];

crypto/stack/stack.c:383:9: 
    381.   {
    382.       if (i < 0 || i >= st->num)
    383. >         return NULL;
    384.       return (void *)st->data[i];
    385.   }

crypto/stack/stack.c:385:1: return from a call to OPENSSL_sk_value
    383.           return NULL;
    384.       return (void *)st->data[i];
    385. > }
    386.   
    387.   void *OPENSSL_sk_set(OPENSSL_STACK *st, int i, const void *data)

include/openssl/x509.h:99:1: return from a call to sk_X509_value
  97.   typedef struct x509_cinf_st X509_CINF;
  98.   
  99. > DEFINE_STACK_OF(X509)
  100.   
  101.   /* This is used for a table of trust checking functions */

crypto/x509/x509_vfy.c:874:5: 
872.       X509 *x = sk_X509_value(ctx->chain, cnum);
873.   
874. >     ctx->current_cert = x;
875.       ctx->current_issuer = NULL;
876.       ctx->current_crl_score = 0;

crypto/x509/x509_vfy.c:875:5: 
873.   
874.       ctx->current_cert = x;
875. >     ctx->current_issuer = NULL;
876.       ctx->current_crl_score = 0;
877.       ctx->current_reasons = 0;

crypto/x509/x509_vfy.c:876:5: 
874.       ctx->current_cert = x;
875.       ctx->current_issuer = NULL;
876. >     ctx->current_crl_score = 0;
877.       ctx->current_reasons = 0;
878.   

crypto/x509/x509_vfy.c:877:5: 
875.       ctx->current_issuer = NULL;
876.       ctx->current_crl_score = 0;
877. >     ctx->current_reasons = 0;
878.   
879.       if (x->ex_flags & EXFLAG_PROXY)

crypto/x509/x509_vfy.c:879:9: 
877.       ctx->current_reasons = 0;
878.   
879. >     if (x->ex_flags & EXFLAG_PROXY)
880.           return 1;
881.   

static int check_cert(X509_STORE_CTX *ctx)
{
    X509_CRL *crl = NULL, *dcrl = NULL;
    int ok = 0;
    int cnum = ctx->error_depth;
    X509 *x = sk_X509_value(ctx->chain, cnum);
    ctx->current_cert = x;
    ctx->current_issuer = NULL;
    ctx->current_crl_score = 0;
    ctx->current_reasons = 0;
    if (x->ex_flags & EXFLAG_PROXY)
        return 1;
    while (ctx->current_reasons != CRLDP_ALL_REASONS) {
        unsigned int last_reasons = ctx->current_reasons;
        if (ctx->get_crl)
            ok = ctx->get_crl(ctx, &crl, x);
        else
            ok = get_crl_delta(ctx, &crl, &dcrl, x);
        if (!ok) {
            ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);
            goto done;
        }
        ctx->current_crl = crl;
        ok = ctx->check_crl(ctx, crl);
        if (!ok)
            goto done;
        if (dcrl) {
            ok = ctx->check_crl(ctx, dcrl);
            if (!ok)
                goto done;
            ok = ctx->cert_crl(ctx, dcrl, x);
            if (!ok)
                goto done;
        } else
            ok = 1;
        if (ok != 2) {
            ok = ctx->cert_crl(ctx, crl, x);
            if (!ok)
                goto done;
        }
        X509_CRL_free(crl);
        X509_CRL_free(dcrl);
        crl = NULL;
        dcrl = NULL;
        if (last_reasons == ctx->current_reasons) {
            ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);
            goto done;
        }
    }
 done:
    X509_CRL_free(crl);
    X509_CRL_free(dcrl);
    ctx->current_crl = NULL;
    return ok;
}
['static int check_cert(X509_STORE_CTX *ctx)\n{\n    X509_CRL *crl = NULL, *dcrl = NULL;\n    int ok = 0;\n    int cnum = ctx->error_depth;\n    X509 *x = sk_X509_value(ctx->chain, cnum);\n    ctx->current_cert = x;\n    ctx->current_issuer = NULL;\n    ctx->current_crl_score = 0;\n    ctx->current_reasons = 0;\n    if (x->ex_flags & EXFLAG_PROXY)\n        return 1;\n    while (ctx->current_reasons != CRLDP_ALL_REASONS) {\n        unsigned int last_reasons = ctx->current_reasons;\n        if (ctx->get_crl)\n            ok = ctx->get_crl(ctx, &crl, x);\n        else\n            ok = get_crl_delta(ctx, &crl, &dcrl, x);\n        if (!ok) {\n            ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);\n            goto done;\n        }\n        ctx->current_crl = crl;\n        ok = ctx->check_crl(ctx, crl);\n        if (!ok)\n            goto done;\n        if (dcrl) {\n            ok = ctx->check_crl(ctx, dcrl);\n            if (!ok)\n                goto done;\n            ok = ctx->cert_crl(ctx, dcrl, x);\n            if (!ok)\n                goto done;\n        } else\n            ok = 1;\n        if (ok != 2) {\n            ok = ctx->cert_crl(ctx, crl, x);\n            if (!ok)\n                goto done;\n        }\n        X509_CRL_free(crl);\n        X509_CRL_free(dcrl);\n        crl = NULL;\n        dcrl = NULL;\n        if (last_reasons == ctx->current_reasons) {\n            ok = verify_cb_crl(ctx, X509_V_ERR_UNABLE_TO_GET_CRL);\n            goto done;\n        }\n    }\n done:\n    X509_CRL_free(crl);\n    X509_CRL_free(dcrl);\n    ctx->current_crl = NULL;\n    return ok;\n}', 'DEFINE_STACK_OF(X509)', 'void *OPENSSL_sk_value(const OPENSSL_STACK *st, int i)\n{\n    if (i < 0 || i >= st->num)\n        return NULL;\n    return (void *)st->data[i];\n}']