#include <stdio.h>
#include <ctype.h>
+#include <string.h>
#include "internal/cryptlib.h"
#include <openssl/buffer.h>
#include <openssl/objects.h>
int PEM_do_header(EVP_CIPHER_INFO *cipher, unsigned char *data, long *plen,
pem_password_cb *callback, void *u)
{
- int i = 0, j, o, klen;
- long len;
+ int ok;
+ int keylen;
+ long len = *plen;
+ int ilen = (int) len; /* EVP_DecryptUpdate etc. take int lengths */
EVP_CIPHER_CTX *ctx;
unsigned char key[EVP_MAX_KEY_LENGTH];
char buf[PEM_BUFSIZE];
- len = *plen;
+#if LONG_MAX > INT_MAX
+ /* Check that we did not truncate the length */
+ if (len > INT_MAX) {
+ PEMerr(PEM_F_PEM_DO_HEADER, PEM_R_HEADER_TOO_LONG);
+ return 0;
+ }
+#endif
if (cipher->cipher == NULL)
- return (1);
+ return 1;
if (callback == NULL)
- klen = PEM_def_callback(buf, PEM_BUFSIZE, 0, u);
+ keylen = PEM_def_callback(buf, PEM_BUFSIZE, 0, u);
else
- klen = callback(buf, PEM_BUFSIZE, 0, u);
- if (klen <= 0) {
+ keylen = callback(buf, PEM_BUFSIZE, 0, u);
+ if (keylen <= 0) {
PEMerr(PEM_F_PEM_DO_HEADER, PEM_R_BAD_PASSWORD_READ);
- return (0);
+ return 0;
}
#ifdef CHARSET_EBCDIC
/* Convert the pass phrase from EBCDIC */
- ebcdic2ascii(buf, buf, klen);
+ ebcdic2ascii(buf, buf, keylen);
#endif
if (!EVP_BytesToKey(cipher->cipher, EVP_md5(), &(cipher->iv[0]),
- (unsigned char *)buf, klen, 1, key, NULL))
+ (unsigned char *)buf, keylen, 1, key, NULL))
return 0;
- j = (int)len;
ctx = EVP_CIPHER_CTX_new();
if (ctx == NULL)
return 0;
- o = EVP_DecryptInit_ex(ctx, cipher->cipher, NULL, key, &(cipher->iv[0]));
- if (o)
- o = EVP_DecryptUpdate(ctx, data, &i, data, j);
- if (o)
- o = EVP_DecryptFinal_ex(ctx, &(data[i]), &j);
+
+ ok = EVP_DecryptInit_ex(ctx, cipher->cipher, NULL, key, &(cipher->iv[0]));
+ if (ok)
+ ok = EVP_DecryptUpdate(ctx, data, &ilen, data, ilen);
+ if (ok) {
+ /* Squirrel away the length of data decrypted so far. */
+ *plen = ilen;
+ ok = EVP_DecryptFinal_ex(ctx, &(data[ilen]), &ilen);
+ }
+ if (ok)
+ *plen += ilen;
+ else
+ PEMerr(PEM_F_PEM_DO_HEADER, PEM_R_BAD_DECRYPT);
+
EVP_CIPHER_CTX_free(ctx);
OPENSSL_cleanse((char *)buf, sizeof(buf));
OPENSSL_cleanse((char *)key, sizeof(key));
- if (o)
- j += i;
- else {
- PEMerr(PEM_F_PEM_DO_HEADER, PEM_R_BAD_DECRYPT);
- return (0);
- }
- *plen = j;
- return (1);
+ return ok;
}
+/*
+ * This implements a very limited PEM header parser that does not support the
+ * full grammar of rfc1421. In particular, folded headers are not supported,
+ * nor is additional whitespace.
+ *
+ * A robust implementation would make use of a library that turns the headers
+ * into a BIO from which one folded line is read at a time, and is then split
+ * into a header label and content. We would then parse the content of the
+ * headers we care about. This is overkill for just this limited use-case, but
+ * presumably we also parse rfc822-style headers for S/MIME, so a common
+ * abstraction might well be more generally useful.
+ */
int PEM_get_EVP_CIPHER_INFO(char *header, EVP_CIPHER_INFO *cipher)
{
+ static const char ProcType[] = "Proc-Type:";
+ static const char ENCRYPTED[] = "ENCRYPTED";
+ static const char DEKInfo[] = "DEK-Info:";
const EVP_CIPHER *enc = NULL;
+ int ivlen;
char *dekinfostart, c;
cipher->cipher = NULL;
if ((header == NULL) || (*header == '\0') || (*header == '\n'))
- return (1);
- if (strncmp(header, "Proc-Type: ", 11) != 0) {
+ return 1;
+
+ if (strncmp(header, ProcType, sizeof(ProcType)-1) != 0) {
PEMerr(PEM_F_PEM_GET_EVP_CIPHER_INFO, PEM_R_NOT_PROC_TYPE);
- return (0);
+ return 0;
}
- header += 11;
- if (*header != '4')
- return (0);
- header++;
- if (*header != ',')
- return (0);
- header++;
- if (strncmp(header, "ENCRYPTED", 9) != 0) {
+ header += sizeof(ProcType)-1;
+ header += strspn(header, " \t");
+
+ if (*header++ != '4' || *header++ != ',')
+ return 0;
+ header += strspn(header, " \t");
+
+ /* We expect "ENCRYPTED" followed by optional white-space + line break */
+ if (strncmp(header, ENCRYPTED, sizeof(ENCRYPTED)-1) != 0 ||
+ strspn(header+sizeof(ENCRYPTED)-1, " \t\r\n") == 0) {
PEMerr(PEM_F_PEM_GET_EVP_CIPHER_INFO, PEM_R_NOT_ENCRYPTED);
- return (0);
+ return 0;
}
- for (; (*header != '\n') && (*header != '\0'); header++) ;
- if (*header == '\0') {
+ header += sizeof(ENCRYPTED)-1;
+ header += strspn(header, " \t\r");
+ if (*header++ != '\n') {
PEMerr(PEM_F_PEM_GET_EVP_CIPHER_INFO, PEM_R_SHORT_HEADER);
- return (0);
+ return 0;
}
- header++;
- if (strncmp(header, "DEK-Info: ", 10) != 0) {
+
+ /*-
+ * https://tools.ietf.org/html/rfc1421#section-4.6.1.3
+ * We expect "DEK-Info: algo[,hex-parameters]"
+ */
+ if (strncmp(header, DEKInfo, sizeof(DEKInfo)-1) != 0) {
PEMerr(PEM_F_PEM_GET_EVP_CIPHER_INFO, PEM_R_NOT_DEK_INFO);
- return (0);
+ return 0;
}
- header += 10;
+ header += sizeof(DEKInfo)-1;
+ header += strspn(header, " \t");
+ /*
+ * DEK-INFO is a comma-separated combination of algorithm name and optional
+ * parameters.
+ */
dekinfostart = header;
- for (;;) {
- c = *header;
-#ifndef CHARSET_EBCDIC
- if (!(((c >= 'A') && (c <= 'Z')) || (c == '-') ||
- ((c >= '0') && (c <= '9'))))
- break;
-#else
- if (!(isupper(c) || (c == '-') || isdigit(c)))
- break;
-#endif
- header++;
- }
+ header += strcspn(header, " \t,");
+ c = *header;
*header = '\0';
cipher->cipher = enc = EVP_get_cipherbyname(dekinfostart);
- *header++ = c;
+ *header = c;
+ header += strspn(header, " \t");
if (enc == NULL) {
PEMerr(PEM_F_PEM_GET_EVP_CIPHER_INFO, PEM_R_UNSUPPORTED_ENCRYPTION);
- return (0);
+ return 0;
}
+ ivlen = EVP_CIPHER_iv_length(enc);
+ if (ivlen > 0 && *header++ != ',') {
+ PEMerr(PEM_F_PEM_GET_EVP_CIPHER_INFO, PEM_R_MISSING_DEK_IV);
+ return 0;
+ } else if (ivlen == 0 && *header == ',') {
+ PEMerr(PEM_F_PEM_GET_EVP_CIPHER_INFO, PEM_R_UNEXPECTED_DEK_IV);
+ return 0;
+ }
+
if (!load_iv(&header, cipher->iv, EVP_CIPHER_iv_length(enc)))
- return (0);
+ return 0;
- return (1);
+ return 1;
}
static int load_iv(char **fromp, unsigned char *to, int num)
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