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Diffstat (limited to 'source3/libsmb/smb_seal.c')
| -rw-r--r-- | source3/libsmb/smb_seal.c | 497 |
1 files changed, 497 insertions, 0 deletions
diff --git a/source3/libsmb/smb_seal.c b/source3/libsmb/smb_seal.c new file mode 100644 index 0000000000..b5befbf7cd --- /dev/null +++ b/source3/libsmb/smb_seal.c @@ -0,0 +1,497 @@ +/* + Unix SMB/CIFS implementation. + SMB Transport encryption (sealing) code. + Copyright (C) Jeremy Allison 2007. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "includes.h" + +/****************************************************************************** + Pull out the encryption context for this packet. 0 means global context. +******************************************************************************/ + +NTSTATUS get_enc_ctx_num(const uint8_t *buf, uint16 *p_enc_ctx_num) +{ + if (smb_len(buf) < 8) { + return NT_STATUS_INVALID_BUFFER_SIZE; + } + + if (buf[4] == 0xFF) { + if (buf[5] == 'S' && buf [6] == 'M' && buf[7] == 'B') { + /* Not an encrypted buffer. */ + return NT_STATUS_NOT_FOUND; + } + if (buf[5] == 'E') { + *p_enc_ctx_num = SVAL(buf,6); + return NT_STATUS_OK; + } + } + return NT_STATUS_INVALID_NETWORK_RESPONSE; +} + +/****************************************************************************** + Generic code for client and server. + Is encryption turned on ? +******************************************************************************/ + +bool common_encryption_on(struct smb_trans_enc_state *es) +{ + return ((es != NULL) && es->enc_on); +} + +/****************************************************************************** + Generic code for client and server. + NTLM decrypt an incoming buffer. + Abartlett tells me that SSPI puts the signature first before the encrypted + output, so cope with the same for compatibility. +******************************************************************************/ + +NTSTATUS common_ntlm_decrypt_buffer(NTLMSSP_STATE *ntlmssp_state, char *buf) +{ + NTSTATUS status; + size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */ + size_t data_len; + char *inbuf; + DATA_BLOB sig; + + if (buf_len < 8 + NTLMSSP_SIG_SIZE) { + return NT_STATUS_BUFFER_TOO_SMALL; + } + + inbuf = (char *)smb_xmemdup(buf, buf_len); + + /* Adjust for the signature. */ + data_len = buf_len - 8 - NTLMSSP_SIG_SIZE; + + /* Point at the signature. */ + sig = data_blob_const(inbuf+8, NTLMSSP_SIG_SIZE); + + status = ntlmssp_unseal_packet(ntlmssp_state, + (unsigned char *)inbuf + 8 + NTLMSSP_SIG_SIZE, /* 4 byte len + 0xFF 'E' <enc> <ctx> */ + data_len, + (unsigned char *)inbuf + 8 + NTLMSSP_SIG_SIZE, + data_len, + &sig); + + if (!NT_STATUS_IS_OK(status)) { + SAFE_FREE(inbuf); + return status; + } + + memcpy(buf + 8, inbuf + 8 + NTLMSSP_SIG_SIZE, data_len); + + /* Reset the length and overwrite the header. */ + smb_setlen(buf,data_len + 4); + + SAFE_FREE(inbuf); + return NT_STATUS_OK; +} + +/****************************************************************************** + Generic code for client and server. + NTLM encrypt an outgoing buffer. Return the encrypted pointer in ppbuf_out. + Abartlett tells me that SSPI puts the signature first before the encrypted + output, so do the same for compatibility. +******************************************************************************/ + +NTSTATUS common_ntlm_encrypt_buffer(NTLMSSP_STATE *ntlmssp_state, + uint16 enc_ctx_num, + char *buf, + char **ppbuf_out) +{ + NTSTATUS status; + char *buf_out; + size_t data_len = smb_len(buf) - 4; /* Ignore the 0xFF SMB bytes. */ + DATA_BLOB sig; + + *ppbuf_out = NULL; + + if (data_len == 0) { + return NT_STATUS_BUFFER_TOO_SMALL; + } + + /* + * We know smb_len can't return a value > 128k, so no int overflow + * check needed. + */ + + buf_out = SMB_XMALLOC_ARRAY(char, 8 + NTLMSSP_SIG_SIZE + data_len); + + /* Copy the data from the original buffer. */ + + memcpy(buf_out + 8 + NTLMSSP_SIG_SIZE, buf + 8, data_len); + + smb_set_enclen(buf_out, smb_len(buf) + NTLMSSP_SIG_SIZE, enc_ctx_num); + + sig = data_blob(NULL, NTLMSSP_SIG_SIZE); + + status = ntlmssp_seal_packet(ntlmssp_state, + (unsigned char *)buf_out + 8 + NTLMSSP_SIG_SIZE, /* 4 byte len + 0xFF 'S' <enc> <ctx> */ + data_len, + (unsigned char *)buf_out + 8 + NTLMSSP_SIG_SIZE, + data_len, + &sig); + + if (!NT_STATUS_IS_OK(status)) { + data_blob_free(&sig); + SAFE_FREE(buf_out); + return status; + } + + /* First 16 data bytes are signature for SSPI compatibility. */ + memcpy(buf_out + 8, sig.data, NTLMSSP_SIG_SIZE); + *ppbuf_out = buf_out; + return NT_STATUS_OK; +} + +/****************************************************************************** + Generic code for client and server. + gss-api decrypt an incoming buffer. We insist that the size of the + unwrapped buffer must be smaller or identical to the incoming buffer. +******************************************************************************/ + +#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) +static NTSTATUS common_gss_decrypt_buffer(struct smb_tran_enc_state_gss *gss_state, char *buf) +{ + gss_ctx_id_t gss_ctx = gss_state->gss_ctx; + OM_uint32 ret = 0; + OM_uint32 minor = 0; + int flags_got = 0; + gss_buffer_desc in_buf, out_buf; + size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */ + + if (buf_len < 8) { + return NT_STATUS_BUFFER_TOO_SMALL; + } + + in_buf.value = buf + 8; + in_buf.length = buf_len - 8; + + ret = gss_unwrap(&minor, + gss_ctx, + &in_buf, + &out_buf, + &flags_got, /* did we get sign+seal ? */ + (gss_qop_t *) NULL); + + if (ret != GSS_S_COMPLETE) { + ADS_STATUS adss = ADS_ERROR_GSS(ret, minor); + DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap failed. Error %s\n", + ads_errstr(adss) )); + return map_nt_error_from_gss(ret, minor); + } + + if (out_buf.length > in_buf.length) { + DEBUG(0,("common_gss_encrypt_buffer: gss_unwrap size (%u) too large (%u) !\n", + (unsigned int)out_buf.length, + (unsigned int)in_buf.length )); + gss_release_buffer(&minor, &out_buf); + return NT_STATUS_INVALID_PARAMETER; + } + + memcpy(buf + 8, out_buf.value, out_buf.length); + /* Reset the length and overwrite the header. */ + smb_setlen(buf, out_buf.length + 4); + + gss_release_buffer(&minor, &out_buf); + return NT_STATUS_OK; +} + +/****************************************************************************** + Generic code for client and server. + gss-api encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out. +******************************************************************************/ + +static NTSTATUS common_gss_encrypt_buffer(struct smb_tran_enc_state_gss *gss_state, + uint16 enc_ctx_num, + char *buf, + char **ppbuf_out) +{ + gss_ctx_id_t gss_ctx = gss_state->gss_ctx; + OM_uint32 ret = 0; + OM_uint32 minor = 0; + int flags_got = 0; + gss_buffer_desc in_buf, out_buf; + size_t buf_len = smb_len(buf) + 4; /* Don't forget the 4 length bytes. */ + + *ppbuf_out = NULL; + + if (buf_len < 8) { + return NT_STATUS_BUFFER_TOO_SMALL; + } + + in_buf.value = buf + 8; + in_buf.length = buf_len - 8; + + ret = gss_wrap(&minor, + gss_ctx, + true, /* we want sign+seal. */ + GSS_C_QOP_DEFAULT, + &in_buf, + &flags_got, /* did we get sign+seal ? */ + &out_buf); + + if (ret != GSS_S_COMPLETE) { + ADS_STATUS adss = ADS_ERROR_GSS(ret, minor); + DEBUG(0,("common_gss_encrypt_buffer: gss_wrap failed. Error %s\n", + ads_errstr(adss) )); + return map_nt_error_from_gss(ret, minor); + } + + if (!flags_got) { + /* Sign+seal not supported. */ + gss_release_buffer(&minor, &out_buf); + return NT_STATUS_NOT_SUPPORTED; + } + + /* Ya see - this is why I *hate* gss-api. I don't + * want to have to malloc another buffer of the + * same size + 8 bytes just to get a continuous + * header + buffer, but gss won't let me pass in + * a pre-allocated buffer. Bastards (and you know + * who you are....). I might fix this by + * going to "encrypt_and_send" passing in a file + * descriptor and doing scatter-gather write with + * TCP cork on Linux. But I shouldn't have to + * bother :-*(. JRA. + */ + + *ppbuf_out = (char *)SMB_MALLOC(out_buf.length + 8); /* We know this can't wrap. */ + if (!*ppbuf_out) { + gss_release_buffer(&minor, &out_buf); + return NT_STATUS_NO_MEMORY; + } + + memcpy(*ppbuf_out+8, out_buf.value, out_buf.length); + smb_set_enclen(*ppbuf_out, out_buf.length + 4, enc_ctx_num); + + gss_release_buffer(&minor, &out_buf); + return NT_STATUS_OK; +} +#endif + +/****************************************************************************** + Generic code for client and server. + Encrypt an outgoing buffer. Return the alloced encrypted pointer in buf_out. +******************************************************************************/ + +NTSTATUS common_encrypt_buffer(struct smb_trans_enc_state *es, char *buffer, char **buf_out) +{ + if (!common_encryption_on(es)) { + /* Not encrypting. */ + *buf_out = buffer; + return NT_STATUS_OK; + } + + switch (es->smb_enc_type) { + case SMB_TRANS_ENC_NTLM: + return common_ntlm_encrypt_buffer(es->s.ntlmssp_state, es->enc_ctx_num, buffer, buf_out); +#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) + case SMB_TRANS_ENC_GSS: + return common_gss_encrypt_buffer(es->s.gss_state, es->enc_ctx_num, buffer, buf_out); +#endif + default: + return NT_STATUS_NOT_SUPPORTED; + } +} + +/****************************************************************************** + Generic code for client and server. + Decrypt an incoming SMB buffer. Replaces the data within it. + New data must be less than or equal to the current length. +******************************************************************************/ + +NTSTATUS common_decrypt_buffer(struct smb_trans_enc_state *es, char *buf) +{ + if (!common_encryption_on(es)) { + /* Not decrypting. */ + return NT_STATUS_OK; + } + + switch (es->smb_enc_type) { + case SMB_TRANS_ENC_NTLM: + return common_ntlm_decrypt_buffer(es->s.ntlmssp_state, buf); +#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) + case SMB_TRANS_ENC_GSS: + return common_gss_decrypt_buffer(es->s.gss_state, buf); +#endif + default: + return NT_STATUS_NOT_SUPPORTED; + } +} + +#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) +/****************************************************************************** + Shutdown a gss encryption state. +******************************************************************************/ + +static void common_free_gss_state(struct smb_tran_enc_state_gss **pp_gss_state) +{ + OM_uint32 minor = 0; + struct smb_tran_enc_state_gss *gss_state = *pp_gss_state; + + if (gss_state->creds != GSS_C_NO_CREDENTIAL) { + gss_release_cred(&minor, &gss_state->creds); + } + if (gss_state->gss_ctx != GSS_C_NO_CONTEXT) { + gss_delete_sec_context(&minor, &gss_state->gss_ctx, NULL); + } + SAFE_FREE(*pp_gss_state); +} +#endif + +/****************************************************************************** + Shutdown an encryption state. +******************************************************************************/ + +void common_free_encryption_state(struct smb_trans_enc_state **pp_es) +{ + struct smb_trans_enc_state *es = *pp_es; + + if (es == NULL) { + return; + } + + if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) { + if (es->s.ntlmssp_state) { + ntlmssp_end(&es->s.ntlmssp_state); + } + } +#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) + if (es->smb_enc_type == SMB_TRANS_ENC_GSS) { + /* Free the gss context handle. */ + if (es->s.gss_state) { + common_free_gss_state(&es->s.gss_state); + } + } +#endif + SAFE_FREE(es); + *pp_es = NULL; +} + +/****************************************************************************** + Free an encryption-allocated buffer. +******************************************************************************/ + +void common_free_enc_buffer(struct smb_trans_enc_state *es, char *buf) +{ + if (!common_encryption_on(es)) { + return; + } + + if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) { + SAFE_FREE(buf); + return; + } + +#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) + if (es->smb_enc_type == SMB_TRANS_ENC_GSS) { + OM_uint32 min; + gss_buffer_desc rel_buf; + rel_buf.value = buf; + rel_buf.length = smb_len(buf) + 4; + gss_release_buffer(&min, &rel_buf); + } +#endif +} + +/****************************************************************************** + Client side encryption. +******************************************************************************/ + +/****************************************************************************** + Is client encryption on ? +******************************************************************************/ + +bool cli_encryption_on(struct cli_state *cli) +{ + /* If we supported multiple encrytion contexts + * here we'd look up based on tid. + */ + return common_encryption_on(cli->trans_enc_state); +} + +/****************************************************************************** + Shutdown a client encryption state. +******************************************************************************/ + +void cli_free_encryption_context(struct cli_state *cli) +{ + common_free_encryption_state(&cli->trans_enc_state); +} + +/****************************************************************************** + Free an encryption-allocated buffer. +******************************************************************************/ + +void cli_free_enc_buffer(struct cli_state *cli, char *buf) +{ + /* We know this is an smb buffer, and we + * didn't malloc, only copy, for a keepalive, + * so ignore non-session messages. */ + + if(CVAL(buf,0)) { + return; + } + + /* If we supported multiple encrytion contexts + * here we'd look up based on tid. + */ + common_free_enc_buffer(cli->trans_enc_state, buf); +} + +/****************************************************************************** + Decrypt an incoming buffer. +******************************************************************************/ + +NTSTATUS cli_decrypt_message(struct cli_state *cli) +{ + NTSTATUS status; + uint16 enc_ctx_num; + + /* Ignore non-session messages. */ + if(CVAL(cli->inbuf,0)) { + return NT_STATUS_OK; + } + + status = get_enc_ctx_num((const uint8_t *)cli->inbuf, &enc_ctx_num); + if (!NT_STATUS_IS_OK(status)) { + return status; + } + + if (enc_ctx_num != cli->trans_enc_state->enc_ctx_num) { + return NT_STATUS_INVALID_HANDLE; + } + + return common_decrypt_buffer(cli->trans_enc_state, cli->inbuf); +} + +/****************************************************************************** + Encrypt an outgoing buffer. Return the encrypted pointer in buf_out. +******************************************************************************/ + +NTSTATUS cli_encrypt_message(struct cli_state *cli, char **buf_out) +{ + /* Ignore non-session messages. */ + if(CVAL(cli->outbuf,0)) { + return NT_STATUS_OK; + } + + /* If we supported multiple encrytion contexts + * here we'd look up based on tid. + */ + return common_encrypt_buffer(cli->trans_enc_state, cli->outbuf, buf_out); +} |