strcasecmp: implement strcasecmp and strncasecmp

Rather than relying on the locale code working, instead implement these
functions directly.

Fixes #18322

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/18344)

crypto/init.c

@@ -442,9 +442,6 @@ void OPENSSL_cleanup(void)
     OSSL_TRACE(INIT, "OPENSSL_cleanup: ossl_trace_cleanup()\n");
     ossl_trace_cleanup();
 
-    OSSL_TRACE(INIT, "OPENSSL_cleanup: ossl_deinit_casecmp()\n");
-    ossl_deinit_casecmp();
-
     base_inited = 0;
 }
 
@@ -484,9 +481,6 @@ int OPENSSL_init_crypto(uint64_t opts, const OPENSSL_INIT_SETTINGS *settings)
         aloaddone = 1;
     }
 
-    if (!ossl_init_casecmp())
-        return 0;
-
     /*
      * At some point we should look at this function with a view to moving
      * most/all of this into OSSL_LIB_CTX.

crypto/o_str.c

@@ -10,13 +10,8 @@
 #include "internal/e_os.h"
 #include <string.h>
 #include <limits.h>
-#ifndef OPENSSL_NO_LOCALE
-# include <locale.h>
-# ifdef OPENSSL_SYS_MACOSX
-#  include <xlocale.h>
-# endif
-#endif
 #include <openssl/crypto.h>
+#include "crypto/ctype.h"
 #include "internal/cryptlib.h"
 #include "internal/thread_once.h"
 
@@ -347,94 +342,25 @@ int openssl_strerror_r(int errnum, char *buf, size_t buflen)
 #endif
 }
 
-#ifndef OPENSSL_NO_LOCALE
-# ifndef FIPS_MODULE
-static CRYPTO_ONCE casecmp = CRYPTO_ONCE_STATIC_INIT;
-DEFINE_RUN_ONCE_STATIC(init_casecmp)
-{
-    int ret = ossl_init_casecmp_int();
-
-    return ret;
-}
-
-int ossl_init_casecmp(void)
-{
-    if (!RUN_ONCE(&casecmp, init_casecmp))
-        return 0;
-    return 1;
-}
-# endif
-
-static locale_t loc;
-
-static locale_t ossl_c_locale(void)
-{
-# ifndef FIPS_MODULE
-    if (!ossl_init_casecmp())
-        return (locale_t)0;
-# endif
-    return loc;
-}
-
-int ossl_init_casecmp_int(void)
-{
-# ifdef OPENSSL_SYS_WINDOWS
-    loc = _create_locale(LC_COLLATE, "C");
-# else
-    loc = newlocale(LC_COLLATE_MASK, "C", (locale_t) 0);
-# endif
-    return (loc == (locale_t)0) ? 0 : 1;
-}
-
-void ossl_deinit_casecmp(void)
-{
-    if (loc != (locale_t)0) {
-        freelocale(loc);
-        loc = (locale_t)0;
-    }
-}
-
 int OPENSSL_strcasecmp(const char *s1, const char *s2)
 {
-    locale_t l = ossl_c_locale();
+    int t;
 
-    /* Fallback in case of locale initialization failure */
-    if (l == (locale_t)0)
-        return strcasecmp(s1, s2);
-    return strcasecmp_l(s1, s2, l);
+    while ((t = ossl_tolower(*s1) - ossl_tolower(*s2++)) == 0)
+        if (*s1++ == '\0')
+            return 0;
+    return t;
 }
 
 int OPENSSL_strncasecmp(const char *s1, const char *s2, size_t n)
 {
-    locale_t l = ossl_c_locale();
+    int t;
+    size_t i;
 
-    /* Fallback in case of locale initialization failure */
-    if (l == (locale_t)0)
-        return strncasecmp(s1, s2, n);
-    return strncasecmp_l(s1, s2, n, l);
+    for (i = 0; i < n; i++)
+        if ((t = ossl_tolower(*s1) - ossl_tolower(*s2++)) != 0)
+            return t;
+        else if (*s1++ == '\0')
+            return 0;
+    return 0;
 }
-#else
-int ossl_init_casecmp(void)
-{
-    return 1;
-}
-
-int ossl_init_casecmp_int(void)
-{
-    return 1;
-}
-
-void ossl_deinit_casecmp(void)
-{
-}
-
-int OPENSSL_strcasecmp(const char *s1, const char *s2)
-{
-    return strcasecmp(s1, s2);
-}
-
-int OPENSSL_strncasecmp(const char *s1, const char *s2, size_t n)
-{
-    return strncasecmp(s1, s2, n);
-}
-#endif

include/internal/cryptlib.h

@@ -157,7 +157,4 @@ char *ossl_ipaddr_to_asc(unsigned char *p, int len);
 char *ossl_buf2hexstr_sep(const unsigned char *buf, long buflen, char sep);
 unsigned char *ossl_hexstr2buf_sep(const char *str, long *buflen,
                                    const char sep);
-int ossl_init_casecmp_int(void);
-int ossl_init_casecmp(void);
-void ossl_deinit_casecmp(void);
 #endif

providers/fips/fipsprov.c

@@ -483,7 +483,6 @@ static void fips_teardown(void *provctx)
 {
     OSSL_LIB_CTX_free(PROV_LIBCTX_OF(provctx));
     ossl_prov_ctx_free(provctx);
-    ossl_deinit_casecmp();
 }
 
 static void fips_intern_teardown(void *provctx)
@@ -541,8 +540,6 @@ int OSSL_provider_init_int(const OSSL_CORE_HANDLE *handle,
 
     memset(&selftest_params, 0, sizeof(selftest_params));
 
-    if (!ossl_init_casecmp_int())
-        return 0;
     if (!ossl_prov_seeding_from_dispatch(in))
         goto err;
     for (; in->function_id != 0; in++) {