split-up into multiple C files

... and slightly optimize multiple things, e.g. `DEK-Info` decoding

Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>

Author: sjaeckel

src/headers/tomcrypt_misc.h

@@ -160,8 +160,8 @@ int padding_depad(const unsigned char *data, unsigned long *length, unsigned lon
 #endif  /* LTC_PADDING */
 
 #ifdef LTC_PEM
-int pem_decode_filehandle(FILE *f, ltc_pka_key *k, password_ctx *pw_ctx);
-int pem_decode(const void *buf, unsigned long len, ltc_pka_key *k, password_ctx *pw_ctx);
+int pem_decode_pkcs_filehandle(FILE *f, ltc_pka_key *k, password_ctx *pw_ctx);
+int pem_decode_pkcs(const void *buf, unsigned long len, ltc_pka_key *k, password_ctx *pw_ctx);
 
 #ifdef LTC_SSH
 int pem_decode_openssh_filehandle(FILE *f, ltc_pka_key *k, password_ctx *pw_ctx);

src/headers/tomcrypt_private.h

@@ -219,6 +219,7 @@ int base64_encode_pem(const unsigned char *in,  unsigned long inlen,
 
 /* PEM related */
 
+#ifdef LTC_PEM
 struct password {
    /* usually a `char*` but could also contain binary data
     * so use a `void*` + length to be on the safe side.
@@ -242,7 +243,12 @@ struct str {
 #define SET_STR(n, s) n.p = s, n.len = XSTRLEN(s)
 #define SET_CSTR(n, s) n.p = (char*)s, n.len = XSTRLEN(s)
 #define COPY_STR(n, s, l) do { XMEMCPY(n.p, s, l); n.len = l; } while(0)
-#define FREE_STR(n) do { n.p = NULL; n.len = 0; } while(0)
+#define RESET_STR(n) do { n.p = NULL; n.len = 0; } while(0)
+
+struct dek_info_from_str {
+   const struct str id;
+   struct dek_info info;
+};
 
 enum more_headers {
    no,
@@ -266,14 +272,21 @@ struct pem_headers {
    struct password *pw;
 };
 
+extern const struct pem_header_id pem_std_headers[];
+extern const unsigned long pem_std_headers_num;
+extern const struct str pem_proc_type_encrypted;
+extern const struct str pem_dek_info_start;
+extern const struct dek_info_from_str pem_dek_infos[];
+extern const unsigned long pem_dek_infos_num;
+
 struct bufp {
    /* `end` points to one byte after the last
     * element of the allocated buffer
     */
-   char *p, *r, *end;
+   char *start, *work, *end;
 };
 
-#define SET_BUFP(n, d, l) n.p = (char*)d, n.r = (char*)d, n.end = (char*)d + l + 1
+#define SET_BUFP(n, d, l) n.start = (char*)d, n.work = (char*)d, n.end = (char*)d + l + 1
 
 struct get_char {
    int (*get)(struct get_char*);
@@ -284,6 +297,7 @@ struct get_char {
    struct str unget_buf;
    char unget_buf_[LTC_PEM_DECODE_BUFSZ];
 };
+#endif
 
 /* others */
 

src/misc/pem/pem.c

@@ -0,0 +1,67 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
+/* SPDX-License-Identifier: Unlicense */
+#include "tomcrypt_private.h"
+
+/**
+  @file pem.c
+  Const declarations for PEM, Steffen Jaeckel
+*/
+
+#ifdef LTC_PEM
+
+const struct pem_header_id pem_std_headers[] = {
+   {
+     /* PKCS#8 encrypted */
+     SET_CSTR(.start, "-----BEGIN ENCRYPTED PRIVATE KEY-----"),
+     SET_CSTR(.end, "-----END ENCRYPTED PRIVATE KEY-----"),
+     .has_more_headers = no,
+     .encrypted = 1,
+     .pkcs8 = 1,
+   },
+   {
+     /* PKCS#8 plain */
+     SET_CSTR(.start, "-----BEGIN PRIVATE KEY-----"),
+     SET_CSTR(.end, "-----END PRIVATE KEY-----"),
+     .has_more_headers = no,
+     .pkcs8 = 1,
+   },
+   /* Regular plain or encrypted private keys */
+   {
+     SET_CSTR(.start, "-----BEGIN RSA PRIVATE KEY-----"),
+     SET_CSTR(.end, "-----END RSA PRIVATE KEY-----"),
+     .has_more_headers = maybe,
+     .pka = LTC_PKA_RSA,
+   },
+   {
+     SET_CSTR(.start, "-----BEGIN EC PRIVATE KEY-----"),
+     SET_CSTR(.end, "-----END EC PRIVATE KEY-----"),
+     .has_more_headers = maybe,
+     .pka = LTC_PKA_EC,
+   },
+   {
+     SET_CSTR(.start, "-----BEGIN DSA PRIVATE KEY-----"),
+     SET_CSTR(.end, "-----END DSA PRIVATE KEY-----"),
+     .has_more_headers = maybe,
+     .pka = LTC_PKA_DSA,
+   },
+};
+const unsigned long pem_std_headers_num = sizeof(pem_std_headers)/sizeof(pem_std_headers[0]);
+
+
+/* Encrypted PEM files */
+const struct str pem_proc_type_encrypted = { SET_CSTR(, "Proc-Type: 4,ENCRYPTED") };
+const struct str pem_dek_info_start = { SET_CSTR(, "DEK-Info: ") };
+const struct dek_info_from_str pem_dek_infos[] =
+   {
+      { SET_CSTR(.id, "AES-128-CBC,"),      .info.alg = "aes",      .info.keylen = 128 / 8, },
+      { SET_CSTR(.id, "AES-192-CBC,"),      .info.alg = "aes",      .info.keylen = 192 / 8, },
+      { SET_CSTR(.id, "AES-256-CBC,"),      .info.alg = "aes",      .info.keylen = 256 / 8, },
+      { SET_CSTR(.id, "CAMELLIA-128-CBC,"), .info.alg = "camellia", .info.keylen = 128 / 8, },
+      { SET_CSTR(.id, "CAMELLIA-192-CBC,"), .info.alg = "camellia", .info.keylen = 192 / 8, },
+      { SET_CSTR(.id, "CAMELLIA-256-CBC,"), .info.alg = "camellia", .info.keylen = 256 / 8, },
+      { SET_CSTR(.id, "DES-EDE3-CBC,"),     .info.alg = "3des",     .info.keylen = 192 / 8, },
+      { SET_CSTR(.id, "DES-CBC,"),          .info.alg = "des",      .info.keylen = 64 / 8, },
+   };
+const unsigned long pem_dek_infos_num = sizeof(pem_dek_infos)/sizeof(pem_dek_infos[0]);
+
+#endif /* LTC_PEM */