pk: use common header/footer macros for pkwrite and pkparse

Signed-off-by: Valerio Setti <valerio.setti@nordicsemi.no>
diff --git a/library/pk_internal.h b/library/pk_internal.h
index 571b57e..ae32955 100644
--- a/library/pk_internal.h
+++ b/library/pk_internal.h
@@ -21,6 +21,20 @@
 #include "psa/crypto.h"
 #endif
 
+/* Headers/footers for PEM files */
+#define PEM_BEGIN_PUBLIC_KEY    "-----BEGIN PUBLIC KEY-----"
+#define PEM_END_PUBLIC_KEY      "-----END PUBLIC KEY-----"
+#define PEM_BEGIN_PRIVATE_KEY_RSA   "-----BEGIN RSA PRIVATE KEY-----"
+#define PEM_END_PRIVATE_KEY_RSA     "-----END RSA PRIVATE KEY-----"
+#define PEM_BEGIN_PUBLIC_KEY_RSA     "-----BEGIN RSA PUBLIC KEY-----"
+#define PEM_END_PUBLIC_KEY_RSA     "-----END RSA PUBLIC KEY-----"
+#define PEM_BEGIN_PRIVATE_KEY_EC    "-----BEGIN EC PRIVATE KEY-----"
+#define PEM_END_PRIVATE_KEY_EC      "-----END EC PRIVATE KEY-----"
+#define PEM_BEGIN_PRIVATE_KEY_PKCS8 "-----BEGIN PRIVATE KEY-----"
+#define PEM_END_PRIVATE_KEY_PKCS8   "-----END PRIVATE KEY-----"
+#define PEM_BEGIN_ENCRYPTED_PRIVATE_KEY_PKCS8 "-----BEGIN ENCRYPTED PRIVATE KEY-----"
+#define PEM_END_ENCRYPTED_PRIVATE_KEY_PKCS8   "-----END ENCRYPTED PRIVATE KEY-----"
+
 #if defined(MBEDTLS_PSA_CRYPTO_C)
 #include "psa_util_internal.h"
 #define PSA_PK_TO_MBEDTLS_ERR(status) psa_pk_status_to_mbedtls(status)
diff --git a/library/pkparse.c b/library/pkparse.c
index 3bb5f7b..608c854 100644
--- a/library/pkparse.c
+++ b/library/pkparse.c
@@ -1534,8 +1534,7 @@
         ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
     } else {
         ret = mbedtls_pem_read_buffer(&pem,
-                                      "-----BEGIN RSA PRIVATE KEY-----",
-                                      "-----END RSA PRIVATE KEY-----",
+                                      PEM_BEGIN_PRIVATE_KEY_RSA, PEM_END_PRIVATE_KEY_RSA,
                                       key, pwd, pwdlen, &len);
     }
 
@@ -1564,8 +1563,8 @@
         ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
     } else {
         ret = mbedtls_pem_read_buffer(&pem,
-                                      "-----BEGIN EC PRIVATE KEY-----",
-                                      "-----END EC PRIVATE KEY-----",
+                                      PEM_BEGIN_PRIVATE_KEY_EC,
+                                      PEM_END_PRIVATE_KEY_EC,
                                       key, pwd, pwdlen, &len);
     }
     if (ret == 0) {
@@ -1594,8 +1593,7 @@
         ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
     } else {
         ret = mbedtls_pem_read_buffer(&pem,
-                                      "-----BEGIN PRIVATE KEY-----",
-                                      "-----END PRIVATE KEY-----",
+                                      PEM_BEGIN_PRIVATE_KEY_PKCS8, PEM_END_PRIVATE_KEY_PKCS8,
                                       key, NULL, 0, &len);
     }
     if (ret == 0) {
@@ -1616,8 +1614,8 @@
         ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
     } else {
         ret = mbedtls_pem_read_buffer(&pem,
-                                      "-----BEGIN ENCRYPTED PRIVATE KEY-----",
-                                      "-----END ENCRYPTED PRIVATE KEY-----",
+                                      PEM_BEGIN_ENCRYPTED_PRIVATE_KEY_PKCS8,
+                                      PEM_END_ENCRYPTED_PRIVATE_KEY_PKCS8,
                                       key, NULL, 0, &len);
     }
     if (ret == 0) {
@@ -1743,8 +1741,7 @@
         ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
     } else {
         ret = mbedtls_pem_read_buffer(&pem,
-                                      "-----BEGIN RSA PUBLIC KEY-----",
-                                      "-----END RSA PUBLIC KEY-----",
+                                      PEM_BEGIN_PUBLIC_KEY_RSA, PEM_END_PUBLIC_KEY_RSA,
                                       key, NULL, 0, &len);
     }
 
@@ -1777,8 +1774,7 @@
         ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT;
     } else {
         ret = mbedtls_pem_read_buffer(&pem,
-                                      "-----BEGIN PUBLIC KEY-----",
-                                      "-----END PUBLIC KEY-----",
+                                      PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY,
                                       key, NULL, 0, &len);
     }
 
diff --git a/library/pkwrite.c b/library/pkwrite.c
index 11c0204..20961df 100644
--- a/library/pkwrite.c
+++ b/library/pkwrite.c
@@ -724,16 +724,6 @@
 
 #if defined(MBEDTLS_PEM_WRITE_C)
 
-#define PEM_BEGIN_PUBLIC_KEY    "-----BEGIN PUBLIC KEY-----\n"
-#define PEM_END_PUBLIC_KEY      "-----END PUBLIC KEY-----\n"
-
-#define PEM_BEGIN_PRIVATE_KEY_RSA   "-----BEGIN RSA PRIVATE KEY-----\n"
-#define PEM_END_PRIVATE_KEY_RSA     "-----END RSA PRIVATE KEY-----\n"
-#define PEM_BEGIN_PRIVATE_KEY_EC    "-----BEGIN EC PRIVATE KEY-----\n"
-#define PEM_END_PRIVATE_KEY_EC      "-----END EC PRIVATE KEY-----\n"
-#define PEM_BEGIN_PRIVATE_KEY_PKCS8 "-----BEGIN PRIVATE KEY-----\n"
-#define PEM_END_PRIVATE_KEY_PKCS8   "-----END PRIVATE KEY-----\n"
-
 #define PUB_DER_MAX_BYTES                                                   \
     (MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES > MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES ? \
      MBEDTLS_PK_RSA_PUB_DER_MAX_BYTES : MBEDTLS_PK_ECP_PUB_DER_MAX_BYTES)