private - ltc_algname_match (relaxed alg name matching)

Author: karel-m

src/headers/tomcrypt_private.h

@@ -511,6 +511,9 @@ struct get_char {
 void copy_or_zeromem(const unsigned char* src, unsigned char* dest, unsigned long len, int coz);
 void password_free(struct password *pw, const struct password_ctx *ctx);
 
+/* Case-insensitive ASCII compare that ignores ' ', '-' and '_'. Returns 1 on match, 0 otherwise. */
+int ltc_algname_match(const char *left, const char *right);
+
 int ltc_compare_testvector(const void* is, const unsigned long is_len, const void* should, const unsigned long should_len, const char* what, int which);
 int ltc_do_compare_testvector(const void* is, const unsigned long is_len, const void* should, const unsigned long should_len, const char* what, int which);
 

src/misc/algname_match.c

@@ -0,0 +1,40 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+#include "tomcrypt_private.h"
+
+/**
+  @file algname_match.c
+  Shared relaxed name-matching helper for algorithm lookup tables.
+*/
+
+/**
+   Compare two algorithm-name strings.
+
+   Matching is case-insensitive (ASCII) and ignores ' ', '-' and '_' on both sides
+   e.g. "SECP256R1", "secp_256_r1", "secp-256-r1" and "secp 256 r1" all match
+   @param left   First NUL-terminated string
+   @param right  Second NUL-terminated string
+   @return 1 if the strings match under the relaxed rules, 0 otherwise
+*/
+int ltc_algname_match(const char *left, const char *right)
+{
+   char lc_r, lc_l;
+
+   if (left == NULL || right == NULL) return 0;
+
+   while ((*left != '\0') && (*right != '\0')) {
+      while ((*left  == ' ') || (*left  == '-') || (*left  == '_')) left++;
+      while ((*right == ' ') || (*right == '-') || (*right == '_')) right++;
+      if (*left == '\0' || *right == '\0') break;
+      lc_r = *right;
+      lc_l = *left;
+      if ((lc_r >= 'A') && (lc_r <= 'Z')) lc_r += 32;
+      if ((lc_l >= 'A') && (lc_l <= 'Z')) lc_l += 32;
+      if (lc_l != lc_r) return 0;
+      left++;
+      right++;
+   }
+
+   if ((*left == '\0') && (*right == '\0')) return 1;
+   return 0;
+}

src/pk/ecc/ecc_find_curve.c

@@ -189,28 +189,6 @@ static const struct {
    }
 };
 
-/* case-insensitive match + ignore '-', '_', ' ' */
-static int s_name_match(const char *left, const char *right)
-{
-   char lc_r, lc_l;
-
-   while ((*left != '\0') && (*right != '\0')) {
-      while ((*left  == ' ') || (*left  == '-') || (*left  == '_')) left++;
-      while ((*right == ' ') || (*right == '-') || (*right == '_')) right++;
-      if (*left == '\0' || *right == '\0') break;
-      lc_r = *right;
-      lc_l = *left;
-      if ((lc_r >= 'A') && (lc_r <= 'Z')) lc_r += 32;
-      if ((lc_l >= 'A') && (lc_l <= 'Z')) lc_l += 32;
-      if (lc_l != lc_r) return 0;
-      left++;
-      right++;
-   }
-
-   if ((*left == '\0') && (*right == '\0')) return 1;
-   return 0;
-}
-
 int ecc_get_curve_names(const char *oid, const char * const **names)
 {
    unsigned long i;
@@ -241,7 +219,7 @@ int ecc_find_curve(const char *name_or_oid, const ltc_ecc_curve **cu)
          OID = s_curve_names[i].OID;
       }
       for (j = 0; s_curve_names[i].names[j] != NULL && !OID; j++) {
-         if (s_name_match(s_curve_names[i].names[j], name_or_oid)) {
+         if (ltc_algname_match(s_curve_names[i].names[j], name_or_oid)) {
             OID = s_curve_names[i].OID;
          }
       }