From: YASUOKA Masahiko Subject: Re: isakmpd sha2-{384,512} block size To: tech@openbsd.org Date: Wed, 21 Aug 2024 14:07:57 +0900 On Tue, 20 Aug 2024 09:42:48 +0900 (JST) YASUOKA Masahiko wrote: > I noticed isakmpd can't decrypt quick mode messages when the phase-1 > is established with sha2-384 or sha2-512. In hash.c, hmac_init() is > using 64 for the block length, but the block length of sha2-384 or > sha2-512 should be 128. Previous used the fixed local value 64 for the block length. It isn't correct for SHA2-384 or SHA2-512. The diff changes to use the block sizes from the header file from the crypto library. Problems actually happen if we use HMAC-SHA2-384 or -512 for L2TP/IPsec. Below error messages are written in the /var/log/daemon when the error happens. 133854.054627 Default message_parse_payloads: reserved field non-zero: d6 133854.054878 Default dropped message from 100.64.1.3 port 4500 due to notification type PAYLOAD_MALFORMED I verified the diff actually fixes this problem. Let me share my test procedure with a strongswan and its result: # strongswan:/etc/ipsec.conf conn vmm-test keyexchange=ikev1 authby=secret forceencaps=yes leftfirewall=yes right=100.64.2.3 leftprotoport=17/1701 rightprotoport=17/1701 ike=aes256-sha2_512-modp2048! esp=aes256-sha2_512 auto=add type=transport # strongswan:/etc/ipsec.conf 100.64.2.3 : PSK "SECRET" # openbsd:/etc/ipsec.conf ike passive esp transport \ proto udp from { 100.64.2.3 } port 1701 to any \ main auth "hmac-sha2-512" enc "aes" group "modp2048" \ quick auth "hmac-sha2" enc "aes" \ psk "SECRET" Before the patch: 133854.054627 Default message_parse_payloads: reserved field non-zero: d6 133854.054878 Default dropped message from 100.64.1.3 port 4500 due to notification type PAYLOAD_MALFORMED (IPsec SA is not established) After the patch: 134355.816327 Default isakmpd: phase 1 done (as responder): initiator id 100.64.1.3, responder id 100.64.2.3, src: 100.64.2.3 dst: 100.64.1.3 134355.919719 Default isakmpd: quick mode done (as responder): src: 100.64.2.3 dst: 100.64.1.3 (IPsec SA is established) > ok? > > Index: sbin/isakmpd/hash.c > =================================================================== > RCS file: /cvs/src/sbin/isakmpd/hash.c,v > diff -u -p -r1.24 hash.c > --- sbin/isakmpd/hash.c 15 Oct 2015 06:35:54 -0000 1.24 > +++ sbin/isakmpd/hash.c 20 Jul 2024 18:21:40 -0000 > @@ -56,7 +56,7 @@ static unsigned char digest[HASH_MAX]; > > static struct hash hashes[] = { > { > - HASH_MD5, 5, MD5_SIZE, (void *)&Ctx.md5ctx, digest, > + HASH_MD5, 5, MD5_SIZE, MD5_BLOCK_LENGTH, (void *)&Ctx.md5ctx, digest, > sizeof(MD5_CTX), (void *)&Ctx2.md5ctx, > (void (*)(void *))MD5Init, > (void (*)(void *, unsigned char *, unsigned int))MD5Update, > @@ -64,32 +64,32 @@ static struct hash hashes[] = { > hmac_init, > hmac_final > }, { > - HASH_SHA1, 6, SHA1_SIZE, (void *)&Ctx.sha1ctx, digest, > - sizeof(SHA1_CTX), (void *)&Ctx2.sha1ctx, > + HASH_SHA1, 6, SHA1_SIZE, SHA1_BLOCK_LENGTH, (void *)&Ctx.sha1ctx, > + digest, sizeof(SHA1_CTX), (void *)&Ctx2.sha1ctx, > (void (*)(void *))SHA1Init, > (void (*)(void *, unsigned char *, unsigned int))SHA1Update, > (void (*)(unsigned char *, void *))SHA1Final, > hmac_init, > hmac_final > }, { > - HASH_SHA2_256, 7, SHA2_256_SIZE, (void *)&Ctx.sha2ctx, digest, > - sizeof(SHA2_CTX), (void *)&Ctx2.sha2ctx, > + HASH_SHA2_256, 7, SHA2_256_SIZE, SHA256_BLOCK_LENGTH, > + (void *)&Ctx.sha2ctx, digest, sizeof(SHA2_CTX), (void *)&Ctx2.sha2ctx, > (void (*)(void *))SHA256Init, > (void (*)(void *, unsigned char *, unsigned int))SHA256Update, > (void (*)(u_int8_t *, void *))SHA256Final, > hmac_init, > hmac_final > }, { > - HASH_SHA2_384, 8, SHA2_384_SIZE, (void *)&Ctx.sha2ctx, digest, > - sizeof(SHA2_CTX), (void *)&Ctx2.sha2ctx, > + HASH_SHA2_384, 8, SHA2_384_SIZE, SHA384_BLOCK_LENGTH, > + (void *)&Ctx.sha2ctx, digest, sizeof(SHA2_CTX), (void *)&Ctx2.sha2ctx, > (void (*)(void *))SHA384Init, > (void (*)(void *, unsigned char *, unsigned int))SHA384Update, > (void (*)(u_int8_t *, void *))SHA384Final, > hmac_init, > hmac_final > }, { > - HASH_SHA2_512, 9, SHA2_512_SIZE, (void *)&Ctx.sha2ctx, digest, > - sizeof(SHA2_CTX), (void *)&Ctx2.sha2ctx, > + HASH_SHA2_512, 9, SHA2_512_SIZE, SHA512_BLOCK_LENGTH, > + (void *)&Ctx.sha2ctx, digest, sizeof(SHA2_CTX), (void *)&Ctx2.sha2ctx, > (void (*)(void *))SHA512Init, > (void (*)(void *, unsigned char *, unsigned int))SHA512Update, > (void (*)(u_int8_t *, void *))SHA512Final, > @@ -122,11 +122,11 @@ hash_get(enum hashes hashtype) > void > hmac_init(struct hash *hash, unsigned char *okey, unsigned int len) > { > - unsigned int i, blocklen = HMAC_BLOCKLEN; > - unsigned char key[HMAC_BLOCKLEN]; > + unsigned int i; > + unsigned char key[128]; > > - bzero(key, blocklen); > - if (len > blocklen) { > + bzero(key, sizeof(key)); > + if (len > hash->blocklen) { > /* Truncate key down to blocklen */ > hash->Init(hash->ctx); > hash->Update(hash->ctx, okey, len); > @@ -136,19 +136,19 @@ hmac_init(struct hash *hash, unsigned ch > } > > /* HMAC I and O pad computation */ > - for (i = 0; i < blocklen; i++) > + for (i = 0; i < hash->blocklen; i++) > key[i] ^= HMAC_IPAD_VAL; > > hash->Init(hash->ctx); > - hash->Update(hash->ctx, key, blocklen); > + hash->Update(hash->ctx, key, hash->blocklen); > > - for (i = 0; i < blocklen; i++) > + for (i = 0; i < hash->blocklen; i++) > key[i] ^= (HMAC_IPAD_VAL ^ HMAC_OPAD_VAL); > > hash->Init(hash->ctx2); > - hash->Update(hash->ctx2, key, blocklen); > + hash->Update(hash->ctx2, key, hash->blocklen); > > - explicit_bzero(key, blocklen); > + explicit_bzero(key, sizeof(key)); > } > > /* > Index: sbin/isakmpd/hash.h > =================================================================== > RCS file: /cvs/src/sbin/isakmpd/hash.h,v > diff -u -p -r1.8 hash.h > --- sbin/isakmpd/hash.h 10 Jun 2006 20:10:02 -0000 1.8 > +++ sbin/isakmpd/hash.h 20 Jul 2024 18:21:40 -0000 > @@ -53,6 +53,7 @@ struct hash { > enum hashes type; > int id; /* ISAKMP/Oakley ID */ > u_int8_t hashsize; /* Size of the hash */ > + unsigned blocklen; /* The hash's block length */ > void *ctx; /* Pointer to a context, for HMAC ictx */ > unsigned char *digest; /* Pointer to a digest */ > int ctxsize; > @@ -68,7 +69,6 @@ struct hash { > > #define HMAC_IPAD_VAL 0x36 > #define HMAC_OPAD_VAL 0x5C > -#define HMAC_BLOCKLEN 64 > > extern struct hash *hash_get(enum hashes); > extern void hmac_init(struct hash *, unsigned char *, unsigned int); >