From de9c17eb4a912c9028f7b470eb80815144883b26 Mon Sep 17 00:00:00 2001 From: Kevin Coffman Date: Wed, 17 Mar 2010 13:02:59 -0400 Subject: [PATCH] gss_krb5: add support for new token formats in rfc4121 This is a step toward support for AES encryption types which are required to use the new token formats defined in rfc4121. Signed-off-by: Kevin Coffman [SteveD: Fixed a typo in gss_verify_mic_v2()] Signed-off-by: Steve Dickson [Trond: Got rid of the TEST_ROTATE/TEST_EXTRA_COUNT crap] Signed-off-by: Trond Myklebust --- include/linux/sunrpc/gss_krb5.h | 28 +++++ net/sunrpc/auth_gss/gss_krb5_crypto.c | 74 +++++++++++ net/sunrpc/auth_gss/gss_krb5_seal.c | 69 ++++++++++ net/sunrpc/auth_gss/gss_krb5_unseal.c | 61 +++++++++ net/sunrpc/auth_gss/gss_krb5_wrap.c | 174 ++++++++++++++++++++++++++ 5 files changed, 406 insertions(+) diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h index db0522b4c4c9..0085a30fd204 100644 --- a/include/linux/sunrpc/gss_krb5.h +++ b/include/linux/sunrpc/gss_krb5.h @@ -53,6 +53,8 @@ /* Maximum blocksize for the supported crypto algorithms */ #define GSS_KRB5_MAX_BLOCKSIZE (16) +struct krb5_ctx; + struct gss_krb5_enctype { const u32 etype; /* encryption (key) type */ const u32 ctype; /* checksum type */ @@ -75,6 +77,12 @@ struct gss_krb5_enctype { u32 (*mk_key) (const struct gss_krb5_enctype *gk5e, struct xdr_netobj *in, struct xdr_netobj *out); /* complete key generation */ + u32 (*encrypt_v2) (struct krb5_ctx *kctx, u32 offset, + struct xdr_buf *buf, int ec, + struct page **pages); /* v2 encryption function */ + u32 (*decrypt_v2) (struct krb5_ctx *kctx, u32 offset, + struct xdr_buf *buf, u32 *headskip, + u32 *tailskip); /* v2 decryption function */ }; /* krb5_ctx flags definitions */ @@ -112,6 +120,18 @@ extern spinlock_t krb5_seq_lock; #define KG_TOK_MIC_MSG 0x0101 #define KG_TOK_WRAP_MSG 0x0201 +#define KG2_TOK_INITIAL 0x0101 +#define KG2_TOK_RESPONSE 0x0202 +#define KG2_TOK_MIC 0x0404 +#define KG2_TOK_WRAP 0x0504 + +#define KG2_TOKEN_FLAG_SENTBYACCEPTOR 0x01 +#define KG2_TOKEN_FLAG_SEALED 0x02 +#define KG2_TOKEN_FLAG_ACCEPTORSUBKEY 0x04 + +#define KG2_RESP_FLAG_ERROR 0x0001 +#define KG2_RESP_FLAG_DELEG_OK 0x0002 + enum sgn_alg { SGN_ALG_DES_MAC_MD5 = 0x0000, SGN_ALG_MD2_5 = 0x0001, @@ -136,6 +156,9 @@ enum seal_alg { #define CKSUMTYPE_RSA_MD5_DES 0x0008 #define CKSUMTYPE_NIST_SHA 0x0009 #define CKSUMTYPE_HMAC_SHA1_DES3 0x000c +#define CKSUMTYPE_HMAC_SHA1_96_AES128 0x000f +#define CKSUMTYPE_HMAC_SHA1_96_AES256 0x0010 +#define CKSUMTYPE_HMAC_MD5_ARCFOUR -138 /* Microsoft md5 hmac cksumtype */ /* from gssapi_err_krb5.h */ #define KG_CCACHE_NOMATCH (39756032L) @@ -212,6 +235,11 @@ make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen, struct xdr_buf *body, int body_offset, u8 *cksumkey, struct xdr_netobj *cksumout); +u32 +make_checksum_v2(struct krb5_ctx *, char *header, int hdrlen, + struct xdr_buf *body, int body_offset, u8 *key, + struct xdr_netobj *cksum); + u32 gss_get_mic_kerberos(struct gss_ctx *, struct xdr_buf *, struct xdr_netobj *); diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c index bb76873aa019..ca52ac28a537 100644 --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c @@ -197,6 +197,80 @@ out: return err ? GSS_S_FAILURE : 0; } +/* + * checksum the plaintext data and hdrlen bytes of the token header + * Per rfc4121, sec. 4.2.4, the checksum is performed over the data + * body then over the first 16 octets of the MIC token + * Inclusion of the header data in the calculation of the + * checksum is optional. + */ +u32 +make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen, + struct xdr_buf *body, int body_offset, u8 *cksumkey, + struct xdr_netobj *cksumout) +{ + struct hash_desc desc; + struct scatterlist sg[1]; + int err; + u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN]; + unsigned int checksumlen; + + if (kctx->gk5e->keyed_cksum == 0) { + dprintk("%s: expected keyed hash for %s\n", + __func__, kctx->gk5e->name); + return GSS_S_FAILURE; + } + if (cksumkey == NULL) { + dprintk("%s: no key supplied for %s\n", + __func__, kctx->gk5e->name); + return GSS_S_FAILURE; + } + + desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, + CRYPTO_ALG_ASYNC); + if (IS_ERR(desc.tfm)) + return GSS_S_FAILURE; + checksumlen = crypto_hash_digestsize(desc.tfm); + desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; + + err = crypto_hash_setkey(desc.tfm, cksumkey, kctx->gk5e->keylength); + if (err) + goto out; + + err = crypto_hash_init(&desc); + if (err) + goto out; + err = xdr_process_buf(body, body_offset, body->len - body_offset, + checksummer, &desc); + if (err) + goto out; + if (header != NULL) { + sg_init_one(sg, header, hdrlen); + err = crypto_hash_update(&desc, sg, hdrlen); + if (err) + goto out; + } + err = crypto_hash_final(&desc, checksumdata); + if (err) + goto out; + + cksumout->len = kctx->gk5e->cksumlength; + + switch (kctx->gk5e->ctype) { + case CKSUMTYPE_HMAC_SHA1_96_AES128: + case CKSUMTYPE_HMAC_SHA1_96_AES256: + /* note that this truncates the hash */ + memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength); + break; + default: + BUG(); + break; + } +out: + crypto_free_hash(desc.tfm); + return err ? GSS_S_FAILURE : 0; +} + struct encryptor_desc { u8 iv[GSS_KRB5_MAX_BLOCKSIZE]; struct blkcipher_desc desc; diff --git a/net/sunrpc/auth_gss/gss_krb5_seal.c b/net/sunrpc/auth_gss/gss_krb5_seal.c index 7ede900049a7..477a546d19bb 100644 --- a/net/sunrpc/auth_gss/gss_krb5_seal.c +++ b/net/sunrpc/auth_gss/gss_krb5_seal.c @@ -91,6 +91,33 @@ setup_token(struct krb5_ctx *ctx, struct xdr_netobj *token) return (char *)krb5_hdr; } +static void * +setup_token_v2(struct krb5_ctx *ctx, struct xdr_netobj *token) +{ + __be16 *ptr, *krb5_hdr; + u8 *p, flags = 0x00; + + if ((ctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0) + flags |= 0x01; + if (ctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) + flags |= 0x04; + + /* Per rfc 4121, sec 4.2.6.1, there is no header, + * just start the token */ + krb5_hdr = ptr = (__be16 *)token->data; + + *ptr++ = KG2_TOK_MIC; + p = (u8 *)ptr; + *p++ = flags; + *p++ = 0xff; + ptr = (__be16 *)p; + *ptr++ = 0xffff; + *ptr++ = 0xffff; + + token->len = GSS_KRB5_TOK_HDR_LEN + ctx->gk5e->cksumlength; + return krb5_hdr; +} + static u32 gss_get_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *text, struct xdr_netobj *token) @@ -132,6 +159,45 @@ gss_get_mic_v1(struct krb5_ctx *ctx, struct xdr_buf *text, return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE; } +u32 +gss_get_mic_v2(struct krb5_ctx *ctx, struct xdr_buf *text, + struct xdr_netobj *token) +{ + char cksumdata[GSS_KRB5_MAX_CKSUM_LEN]; + struct xdr_netobj cksumobj = { .len = sizeof(cksumdata), + .data = cksumdata}; + void *krb5_hdr; + s32 now; + u64 seq_send; + u8 *cksumkey; + + dprintk("RPC: %s\n", __func__); + + krb5_hdr = setup_token_v2(ctx, token); + + /* Set up the sequence number. Now 64-bits in clear + * text and w/o direction indicator */ + spin_lock(&krb5_seq_lock); + seq_send = ctx->seq_send64++; + spin_unlock(&krb5_seq_lock); + *((u64 *)(krb5_hdr + 8)) = cpu_to_be64(seq_send); + + if (ctx->initiate) + cksumkey = ctx->initiator_sign; + else + cksumkey = ctx->acceptor_sign; + + if (make_checksum_v2(ctx, krb5_hdr, GSS_KRB5_TOK_HDR_LEN, + text, 0, cksumkey, &cksumobj)) + return GSS_S_FAILURE; + + memcpy(krb5_hdr + GSS_KRB5_TOK_HDR_LEN, cksumobj.data, cksumobj.len); + + now = get_seconds(); + + return (ctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE; +} + u32 gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text, struct xdr_netobj *token) @@ -144,6 +210,9 @@ gss_get_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *text, case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: return gss_get_mic_v1(ctx, text, token); + case ENCTYPE_AES128_CTS_HMAC_SHA1_96: + case ENCTYPE_AES256_CTS_HMAC_SHA1_96: + return gss_get_mic_v2(ctx, text, token); } } diff --git a/net/sunrpc/auth_gss/gss_krb5_unseal.c b/net/sunrpc/auth_gss/gss_krb5_unseal.c index 3e15bdb5a9eb..4ede4cc4391f 100644 --- a/net/sunrpc/auth_gss/gss_krb5_unseal.c +++ b/net/sunrpc/auth_gss/gss_krb5_unseal.c @@ -141,6 +141,64 @@ gss_verify_mic_v1(struct krb5_ctx *ctx, return GSS_S_COMPLETE; } +static u32 +gss_verify_mic_v2(struct krb5_ctx *ctx, + struct xdr_buf *message_buffer, struct xdr_netobj *read_token) +{ + char cksumdata[GSS_KRB5_MAX_CKSUM_LEN]; + struct xdr_netobj cksumobj = {.len = sizeof(cksumdata), + .data = cksumdata}; + s32 now; + u64 seqnum; + u8 *ptr = read_token->data; + u8 *cksumkey; + u8 flags; + int i; + + dprintk("RPC: %s\n", __func__); + + if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_MIC) + return GSS_S_DEFECTIVE_TOKEN; + + flags = ptr[2]; + if ((!ctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) || + (ctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR))) + return GSS_S_BAD_SIG; + + if (flags & KG2_TOKEN_FLAG_SEALED) { + dprintk("%s: token has unexpected sealed flag\n", __func__); + return GSS_S_FAILURE; + } + + for (i = 3; i < 8; i++) + if (ptr[i] != 0xff) + return GSS_S_DEFECTIVE_TOKEN; + + if (ctx->initiate) + cksumkey = ctx->acceptor_sign; + else + cksumkey = ctx->initiator_sign; + + if (make_checksum_v2(ctx, ptr, GSS_KRB5_TOK_HDR_LEN, message_buffer, 0, + cksumkey, &cksumobj)) + return GSS_S_FAILURE; + + if (memcmp(cksumobj.data, ptr + GSS_KRB5_TOK_HDR_LEN, + ctx->gk5e->cksumlength)) + return GSS_S_BAD_SIG; + + /* it got through unscathed. Make sure the context is unexpired */ + now = get_seconds(); + if (now > ctx->endtime) + return GSS_S_CONTEXT_EXPIRED; + + /* do sequencing checks */ + + seqnum = be64_to_cpup((__be64 *)ptr + 8); + + return GSS_S_COMPLETE; +} + u32 gss_verify_mic_kerberos(struct gss_ctx *gss_ctx, struct xdr_buf *message_buffer, @@ -154,6 +212,9 @@ gss_verify_mic_kerberos(struct gss_ctx *gss_ctx, case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: return gss_verify_mic_v1(ctx, message_buffer, read_token); + case ENCTYPE_AES128_CTS_HMAC_SHA1_96: + case ENCTYPE_AES256_CTS_HMAC_SHA1_96: + return gss_verify_mic_v2(ctx, message_buffer, read_token); } } diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c index 1c8ebd3dbd3c..4aa46b28298c 100644 --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c @@ -340,6 +340,174 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf) return GSS_S_COMPLETE; } +/* + * We cannot currently handle tokens with rotated data. We need a + * generalized routine to rotate the data in place. It is anticipated + * that we won't encounter rotated data in the general case. + */ +static u32 +rotate_left(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf, u16 rrc) +{ + unsigned int realrrc = rrc % (buf->len - offset - GSS_KRB5_TOK_HDR_LEN); + + if (realrrc == 0) + return 0; + + dprintk("%s: cannot process token with rotated data: " + "rrc %u, realrrc %u\n", __func__, rrc, realrrc); + return 1; +} + +static u32 +gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset, + struct xdr_buf *buf, struct page **pages) +{ + int blocksize; + u8 *ptr, *plainhdr; + s32 now; + u8 flags = 0x00; + __be16 *be16ptr, ec = 0; + __be64 *be64ptr; + u32 err; + + dprintk("RPC: %s\n", __func__); + + if (kctx->gk5e->encrypt_v2 == NULL) + return GSS_S_FAILURE; + + /* make room for gss token header */ + if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN)) + return GSS_S_FAILURE; + + /* construct gss token header */ + ptr = plainhdr = buf->head[0].iov_base + offset; + *ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff); + *ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff); + + if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0) + flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR; + if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0) + flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY; + /* We always do confidentiality in wrap tokens */ + flags |= KG2_TOKEN_FLAG_SEALED; + + *ptr++ = flags; + *ptr++ = 0xff; + be16ptr = (__be16 *)ptr; + + blocksize = crypto_blkcipher_blocksize(kctx->acceptor_enc); + *be16ptr++ = cpu_to_be16(ec); + /* "inner" token header always uses 0 for RRC */ + *be16ptr++ = cpu_to_be16(0); + + be64ptr = (__be64 *)be16ptr; + spin_lock(&krb5_seq_lock); + *be64ptr = cpu_to_be64(kctx->seq_send64++); + spin_unlock(&krb5_seq_lock); + + err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, ec, pages); + if (err) + return err; + + now = get_seconds(); + return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE; +} + +static u32 +gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf) +{ + s32 now; + u64 seqnum; + u8 *ptr; + u8 flags = 0x00; + u16 ec, rrc; + int err; + u32 headskip, tailskip; + u8 decrypted_hdr[GSS_KRB5_TOK_HDR_LEN]; + unsigned int movelen; + + + dprintk("RPC: %s\n", __func__); + + if (kctx->gk5e->decrypt_v2 == NULL) + return GSS_S_FAILURE; + + ptr = buf->head[0].iov_base + offset; + + if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP) + return GSS_S_DEFECTIVE_TOKEN; + + flags = ptr[2]; + if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) || + (kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR))) + return GSS_S_BAD_SIG; + + if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) { + dprintk("%s: token missing expected sealed flag\n", __func__); + return GSS_S_DEFECTIVE_TOKEN; + } + + if (ptr[3] != 0xff) + return GSS_S_DEFECTIVE_TOKEN; + + ec = be16_to_cpup((__be16 *)(ptr + 4)); + rrc = be16_to_cpup((__be16 *)(ptr + 6)); + + seqnum = be64_to_cpup((__be64 *)(ptr + 8)); + + if (rrc != 0) { + err = rotate_left(kctx, offset, buf, rrc); + if (err) + return GSS_S_FAILURE; + } + + err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf, + &headskip, &tailskip); + if (err) + return GSS_S_FAILURE; + + /* + * Retrieve the decrypted gss token header and verify + * it against the original + */ + err = read_bytes_from_xdr_buf(buf, + buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip, + decrypted_hdr, GSS_KRB5_TOK_HDR_LEN); + if (err) { + dprintk("%s: error %u getting decrypted_hdr\n", __func__, err); + return GSS_S_FAILURE; + } + if (memcmp(ptr, decrypted_hdr, 6) + || memcmp(ptr + 8, decrypted_hdr + 8, 8)) { + dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__); + return GSS_S_FAILURE; + } + + /* do sequencing checks */ + + /* it got through unscathed. Make sure the context is unexpired */ + now = get_seconds(); + if (now > kctx->endtime) + return GSS_S_CONTEXT_EXPIRED; + + /* + * Move the head data back to the right position in xdr_buf. + * We ignore any "ec" data since it might be in the head or + * the tail, and we really don't need to deal with it. + * Note that buf->head[0].iov_len may indicate the available + * head buffer space rather than that actually occupied. + */ + movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len); + movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip; + BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen > + buf->head[0].iov_len); + memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen); + buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip; + buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip; + + return GSS_S_COMPLETE; +} + u32 gss_wrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf, struct page **pages) @@ -352,6 +520,9 @@ gss_wrap_kerberos(struct gss_ctx *gctx, int offset, case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: return gss_wrap_kerberos_v1(kctx, offset, buf, pages); + case ENCTYPE_AES128_CTS_HMAC_SHA1_96: + case ENCTYPE_AES256_CTS_HMAC_SHA1_96: + return gss_wrap_kerberos_v2(kctx, offset, buf, pages); } } @@ -366,6 +537,9 @@ gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf) case ENCTYPE_DES_CBC_RAW: case ENCTYPE_DES3_CBC_RAW: return gss_unwrap_kerberos_v1(kctx, offset, buf); + case ENCTYPE_AES128_CTS_HMAC_SHA1_96: + case ENCTYPE_AES256_CTS_HMAC_SHA1_96: + return gss_unwrap_kerberos_v2(kctx, offset, buf); } } -- 2.20.1