Calculate lengths instead of using magic numbers

Yubico · Sep 4, 2024 · c9bae58 · c9bae58
1 parent e23eaa7
commit c9bae58
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/common/util.c b/common/util.c
@@ -70,12 +70,14 @@ bool read_ed25519_key(uint8_t *in, size_t in_len, uint8_t *out,
   uint8_t decoded[128];
   size_t decoded_len = sizeof(decoded);
 
-  if(in_len < (sizeof(PEM_private_header) + sizeof(PEM_private_trailer)-3)) {
+  if (in_len < (sizeof(PEM_private_header) + sizeof(PEM_private_trailer) -
+                3)) { // -3 to account for null bytes in PEM_private_header and
+                      // PEM_private_trailer
     return false;
   }
-  if (memcmp(in, PEM_private_header, sizeof(PEM_private_header)-1) != 0 ||
-      memcmp(in + in_len - sizeof(PEM_private_header), PEM_private_trailer,
-             sizeof(PEM_private_header) - 2) != 0) {
+  if (memcmp(in, PEM_private_header, sizeof(PEM_private_header) - 1) != 0 ||
+      memcmp(in + in_len - (sizeof(PEM_private_trailer) - 1),
+             PEM_private_trailer, sizeof(PEM_private_trailer) - 2) != 0) {
     return false;
   }
 
@@ -107,7 +109,7 @@ bool read_ed25519_key(uint8_t *in, size_t in_len, uint8_t *out,
 
   BIO_free_all(b64);
 
-  if (ret <= 0 || ret != 48) {
+  if (ret != 48) {
     return false;
   }