Replace non-idiomatic strtoul(, 16) to parse a region of 2-character

hex sequences with a low-level replacement designed just for the task.
ok djm

diff --git a/usr.bin/ssh/ssh-pkcs11.c b/usr.bin/ssh/ssh-pkcs11.c
index 0576b1c..74fd120 100644 (file)
--- a/usr.bin/ssh/ssh-pkcs11.c
+++ b/usr.bin/ssh/ssh-pkcs11.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-pkcs11.c,v 1.59 2023/07/27 22:26:49 djm Exp $ */
+/* $OpenBSD: ssh-pkcs11.c,v 1.60 2024/04/02 09:32:28 deraadt Exp $ */
 /*
  * Copyright (c) 2010 Markus Friedl.  All rights reserved.
  * Copyright (c) 2014 Pedro Martelletto. All rights reserved.
@@ -1360,6 +1360,20 @@ pkcs11_rsa_generate_private_key(struct pkcs11_provider *p, CK_ULONG slotidx,
        return pkcs11_fetch_rsa_pubkey(p, slotidx, &pubKey);
 }
 
+static int
+h2i(char c)
+{
+       if (c >= '0' && c <= '9')
+               c -= '0';
+       else if (c >= 'a' && c <= 'f')
+               c -= 'a';
+       else if (c >= 'A' && c <= 'F')
+               c -= 'A';
+       else
+               return -1;
+       return c;
+}
+
 static int
 pkcs11_decode_hex(const char *hex, unsigned char **dest, size_t *rlen)
 {
@@ -1379,11 +1393,13 @@ pkcs11_decode_hex(const char *hex, unsigned char **dest, size_t *rlen)
 
        ptr[2] = '\0';
        for (i = 0; i < len; i++) {
-               ptr[0] = hex[2 * i];
-               ptr[1] = hex[(2 * i) + 1];
-               if (!isxdigit(ptr[0]) || !isxdigit(ptr[1]))
+               int hi, low;
+
+               hi = h2i(hex[2 * i]);
+               lo = h2i(hex[(2 * i) + 1]);
+               if (hi == -1 || lo == -1)
                        return -1;
-               (*dest)[i] = (unsigned char)strtoul(ptr, NULL, 16);
+               (*dest)[i] = (hi << 4) | lo;
        }
 
        if (rlen)