path: root/sbin/dumpon
diff options
authorConrad Meyer <cem@FreeBSD.org>2020-04-23 17:56:48 +0000
committerConrad Meyer <cem@FreeBSD.org>2020-04-23 17:56:48 +0000
commit4647ce4fb6ed8e2ac65f663b8513b4a32908810a (patch)
treeda8b54ef6b85f7977dd64bc54d44b34bc954d17a /sbin/dumpon
parent401ae7ca67d6d7c99645a1f18bf9ebd3d87930b7 (diff)
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
Notes: svn path=/head/; revision=360226
Diffstat (limited to 'sbin/dumpon')
1 files changed, 20 insertions, 3 deletions
diff --git a/sbin/dumpon/dumpon.c b/sbin/dumpon/dumpon.c
index d705193d2418..2b710a611af3 100644
--- a/sbin/dumpon/dumpon.c
+++ b/sbin/dumpon/dumpon.c
@@ -77,6 +77,7 @@ __FBSDID("$FreeBSD$");
#include <openssl/err.h>
#include <openssl/pem.h>
+#include <openssl/rand.h>
#include <openssl/rsa.h>
@@ -224,6 +225,18 @@ genkey(const char *pubkeyfile, struct diocskerneldump_arg *kdap)
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.
+ */
+ {
+ unsigned char c[1];
+ RAND_bytes(c, 1);
+ }
if (caph_enter() < 0)
err(1, "Unable to enter capability mode");
@@ -286,8 +299,9 @@ genkey(const char *pubkeyfile, struct diocskerneldump_arg *kdap)
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));
@@ -470,8 +484,11 @@ main(int argc, char *argv[])
- 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();
+ }
if (pubkeyfile != NULL)
errx(EX_UNAVAILABLE,"Unable to use the public key."