ERR: Restore the similarity of ERR_print_error_cb() and ERR_error_string_n()

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/13510)

crypto/err/err.c

@@ -489,11 +489,12 @@ static unsigned long get_error_values(ERR_GET_ACTION g,
     return ret;
 }
 
-void ERR_error_string_n(unsigned long e, char *buf, size_t len)
+void ossl_err_string_int(unsigned long e, const char *func,
+                         char *buf, size_t len)
 {
     char lsbuf[64], rsbuf[256];
     const char *ls, *rs = NULL;
-    unsigned long f = 0, l, r;
+    unsigned long l, r;
 
     if (len == 0)
         return;
@@ -512,24 +513,32 @@ void ERR_error_string_n(unsigned long e, char *buf, size_t len)
      * directly instead.
      */
     r = ERR_GET_REASON(e);
+#ifndef OPENSSL_NO_ERR
     if (ERR_SYSTEM_ERROR(e)) {
         if (openssl_strerror_r(r, rsbuf, sizeof(rsbuf)))
             rs = rsbuf;
     } else {
         rs = ERR_reason_error_string(e);
     }
+#endif
     if (rs == NULL) {
         BIO_snprintf(rsbuf, sizeof(rsbuf), "reason(%lu)", r);
         rs = rsbuf;
     }
 
-    BIO_snprintf(buf, len, "error:%08lX:%s:%s:%s", e, ls, "", rs);
+    BIO_snprintf(buf, len, "error:%08lX:%s:%s:%s", e, ls, func, rs);
     if (strlen(buf) == len - 1) {
         /* Didn't fit; use a minimal format. */
-        BIO_snprintf(buf, len, "err:%lx:%lx:%lx:%lx", e, l, f, r);
+        BIO_snprintf(buf, len, "err:%lx:%lx:%lx:%lx", e, l, 0L, r);
     }
 }
 
+
+void ERR_error_string_n(unsigned long e, char *buf, size_t len)
+{
+    ossl_err_string_int(e, "", buf, len);
+}
+
 /*
  * ERR_error_string_n should be used instead for ret != NULL as
  * ERR_error_string cannot know how large the buffer is

crypto/err/err_local.h

@@ -72,3 +72,5 @@ static ossl_inline void err_clear(ERR_STATE *es, size_t i, int deall)
 }
 
 ERR_STATE *err_get_state_int(void);
+void ossl_err_string_int(unsigned long e, const char *func,
+                         char *buf, size_t len);

crypto/err/err_prn.c

@@ -27,39 +27,21 @@ void ERR_print_errors_cb(int (*cb) (const char *str, size_t len, void *u),
     int line, flags;
 
     while ((l = ERR_get_error_all(&file, &line, &func, &data, &flags)) != 0) {
-        char buf[ERR_PRINT_BUF_SIZE], *hex;
+        char buf[ERR_PRINT_BUF_SIZE] = "";
-        const char *lib, *reason = NULL;
+        char *hex = NULL;
-        char rsbuf[256];
+        int offset;
-        unsigned long r = ERR_GET_REASON(l);
 
-        lib = ERR_lib_error_string(l);
-
-        /*
-         * ERR_reason_error_string() can't safely return system error strings,
-         * since it would call openssl_strerror_r(), which needs a buffer for
-         * thread safety.  So for system errors, we call openssl_strerror_r()
-         * directly instead.
-         */
-        if (ERR_SYSTEM_ERROR(l)) {
-            if (openssl_strerror_r(r, rsbuf, sizeof(rsbuf)))
-                reason = rsbuf;
-        } else {
-            reason = ERR_reason_error_string(l);
-        }
-
-        if (func == NULL)
-            func = "unknown function";
-        if (reason == NULL) {
-            BIO_snprintf(rsbuf, sizeof(rsbuf), "reason(%lu)", r);
-            reason = rsbuf;
-        }
         if ((flags & ERR_TXT_STRING) == 0)
             data = "";
+
         hex = openssl_buf2hexstr_sep((const unsigned char *)&tid, sizeof(tid),
                                      '\0');
-        BIO_snprintf(buf, sizeof(buf), "%s:error::%s:%s:%s:%s:%d:%s\n",
+        BIO_snprintf(buf, sizeof(buf), "%s:", hex == NULL ? "<null>" : hex);
-                     hex == NULL ? "<null>" : hex, lib, func, reason, file,
+        offset = strlen(buf);
-                     line, data);
+        ossl_err_string_int(l, func, buf + offset, sizeof(buf) - offset);
+        offset += strlen(buf + offset);
+        BIO_snprintf(buf + offset, sizeof(buf) - offset, ":%s:%d:%s\n",
+                     file, line, data);
         OPENSSL_free(hex);
         if (cb(buf, strlen(buf), u) <= 0)
             break;              /* abort outputting the error report */