svn commit: r360226 - in head/sbin: decryptcore dumpon
Conrad Meyer
cem at FreeBSD.org
Thu Apr 23 17:56:49 UTC 2020
Author: cem
Date: Thu Apr 23 17:56:48 2020
New Revision: 360226
URL: https://svnweb.freebsd.org/changeset/base/360226
Log:
EKCD: Preload error strings, PRNG seed; use OAEP padding
Preload OpenSSL ERR string data so that the formatted error messages are
vaguely meaningful. Add OpenSSL error information to the RSA_public_encrypt()
operation failure case in one-time key generation.
For obsolescent OpenSSL versions (*cough* FIPS *cough*), pre-seed the PRNG
before entering Cap mode, as old versions of OpenSSL are unaware of kernel
RNG interfaces aside from /dev/random (such as the long-supported kern.arnd, or
the slightly more recent getentropy(3) or getrandom(2)). (RSA_public_encrypt()
wants a seeded PRNG to randomize the "PS" portion of PKCS 1.5 padding or the
"MGF" pseudo-random function in OAEP padding.)
Switch dumpon to encrypt the one-time key with OAEP padding (recommended since
1998; RFC2437) rather than the obsolescent PKCS 1.5 padding (1993; RFC2313).
Switch decryptcore to attempt OAEP decryption first, and try PKCS 1.5
decryption on failure. This is intended only for transition convenience, and
we should obsolete support for non-OAEP padding in a release or two.
Reviewed by: markj
MFC After: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D24534
Modified:
head/sbin/decryptcore/decryptcore.c
head/sbin/dumpon/dumpon.c
Modified: head/sbin/decryptcore/decryptcore.c
==============================================================================
--- head/sbin/decryptcore/decryptcore.c Thu Apr 23 17:46:29 2020 (r360225)
+++ head/sbin/decryptcore/decryptcore.c Thu Apr 23 17:56:48 2020 (r360226)
@@ -219,6 +219,10 @@ decrypt(int ofd, const char *privkeyfile, const char *
if (RSA_private_decrypt(kdk->kdk_encryptedkeysize,
kdk->kdk_encryptedkey, key, privkey,
+ RSA_PKCS1_OAEP_PADDING) != sizeof(key) &&
+ /* Fallback to deprecated, formerly-used PKCS 1.5 padding. */
+ RSA_private_decrypt(kdk->kdk_encryptedkeysize,
+ kdk->kdk_encryptedkey, key, privkey,
RSA_PKCS1_PADDING) != sizeof(key)) {
pjdlog_error("Unable to decrypt key: %s",
ERR_error_string(ERR_get_error(), NULL));
Modified: head/sbin/dumpon/dumpon.c
==============================================================================
--- head/sbin/dumpon/dumpon.c Thu Apr 23 17:46:29 2020 (r360225)
+++ head/sbin/dumpon/dumpon.c Thu Apr 23 17:56:48 2020 (r360226)
@@ -77,6 +77,7 @@ __FBSDID("$FreeBSD$");
#ifdef HAVE_CRYPTO
#include <openssl/err.h>
#include <openssl/pem.h>
+#include <openssl/rand.h>
#include <openssl/rsa.h>
#endif
@@ -224,6 +225,18 @@ genkey(const char *pubkeyfile, struct diocskerneldump_
if (fp == NULL)
err(1, "Unable to open %s", pubkeyfile);
+ /*
+ * Obsolescent OpenSSL only knows about /dev/random, and needs to
+ * pre-seed before entering cap mode. For whatever reason,
+ * RSA_pub_encrypt uses the internal PRNG.
+ */
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+ {
+ unsigned char c[1];
+ RAND_bytes(c, 1);
+ }
+#endif
+
if (caph_enter() < 0)
err(1, "Unable to enter capability mode");
@@ -286,8 +299,9 @@ genkey(const char *pubkeyfile, struct diocskerneldump_
arc4random_buf(kdap->kda_key, sizeof(kdap->kda_key));
if (RSA_public_encrypt(sizeof(kdap->kda_key), kdap->kda_key,
kdap->kda_encryptedkey, pubkey,
- RSA_PKCS1_PADDING) != (int)kdap->kda_encryptedkeysize) {
- errx(1, "Unable to encrypt the one-time key.");
+ RSA_PKCS1_OAEP_PADDING) != (int)kdap->kda_encryptedkeysize) {
+ errx(1, "Unable to encrypt the one-time key: %s",
+ ERR_error_string(ERR_get_error(), NULL));
}
RSA_free(pubkey);
}
@@ -470,8 +484,11 @@ main(int argc, char *argv[])
usage();
#ifdef HAVE_CRYPTO
- if (cipher != KERNELDUMP_ENC_NONE && pubkeyfile == NULL)
+ if (cipher != KERNELDUMP_ENC_NONE && pubkeyfile == NULL) {
errx(EX_USAGE, "-C option requires a public key file.");
+ } else if (pubkeyfile != NULL) {
+ ERR_load_crypto_strings();
+ }
#else
if (pubkeyfile != NULL)
errx(EX_UNAVAILABLE,"Unable to use the public key."
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