1 files changed, 25 insertions, 13 deletions

diff --git a/src/usr.bin/openssl/cms.c b/src/usr.bin/openssl/cms.c
index 7420d0ab8c..458ddb0e3b 100644
--- a/src/usr.bin/openssl/cms.c
+++ b/src/usr.bin/openssl/cms.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: cms.c,v 1.36 2024/08/12 15:34:58 job Exp $ */
+/* $OpenBSD: cms.c,v 1.38 2025/06/07 08:24:15 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project.
  */
@@ -193,15 +193,33 @@ get_cipher_by_name(char *name)
 static int
 cms_opt_cipher(int argc, char **argv, int *argsused)
 {
+        const EVP_CIPHER *cipher;
         char *name = argv[0];
 
         if (*name++ != '-')
                 return (1);
 
-        if ((cfg.cipher = get_cipher_by_name(name)) == NULL)
-                if ((cfg.cipher = EVP_get_cipherbyname(name)) == NULL)
+        if ((cipher = get_cipher_by_name(name)) == NULL)
+                if ((cipher = EVP_get_cipherbyname(name)) == NULL)
                         return (1);
 
+        /*
+         * XXX - this should really be done in CMS_{encrypt,decrypt}() until
+         * we have proper support for AuthEnvelopedData (RFC 5084), but this
+         * is good enough for now to avoid outputting garbage with this rusty
+         * swiss army knife.
+         */
+        if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER) != 0) {
+                BIO_printf(bio_err, "AuthEnvelopedData is not supported\n");
+                return (1);
+        }
+        if (EVP_CIPHER_mode(cipher) == EVP_CIPH_XTS_MODE) {
+                BIO_printf(bio_err, "XTS mode not supported\n");
+                return (1);
+        }
+
+        cfg.cipher = cipher;
+
         *argsused = 1;
         return (0);
 }
@@ -475,7 +493,7 @@ static const struct option cms_options[] = {
         },
         {
                 .name = "aes256",
-                .desc = "Encrypt PEM output with CBC AES",
+                .desc = "Encrypt PEM output with CBC AES (default)",
                 .type = OPTION_ARGV_FUNC,
                 .opt.argvfunc = cms_opt_cipher,
         },
@@ -509,7 +527,7 @@ static const struct option cms_options[] = {
         },
         {
                 .name = "des3",
-                .desc = "Encrypt with triple DES (default)",
+                .desc = "Encrypt with triple DES",
                 .type = OPTION_ARGV_FUNC,
                 .opt.argvfunc = cms_opt_cipher,
         },
@@ -1291,14 +1309,8 @@ cms_main(int argc, char **argv)
         }
 
         if (cfg.operation == SMIME_ENCRYPT) {
-                if (cfg.cipher == NULL) {
-#ifndef OPENSSL_NO_DES
-                        cfg.cipher = EVP_des_ede3_cbc();
-#else
-                        BIO_printf(bio_err, "No cipher selected\n");
-                        goto end;
-#endif
-                }
+                if (cfg.cipher == NULL)
+                        cfg.cipher = EVP_aes_256_cbc();
                 if (cfg.secret_key != NULL &&
                     cfg.secret_keyid == NULL) {
                         BIO_printf(bio_err, "No secret key id\n");