I also removed the line you noted: pr_warn_once("requesting GMAC signing is experimental\n"); No point to print that unless GMAC was actually negotiated (ie until the followon patch which adds GMAC to the list ...) On Thu, Jul 8, 2021 at 6:29 PM Steve French wrote: > > Tentatively I made the change to clarify: > > +MODULE_PARM_DESC(enable_GMAC_signing, "Enable requesting faster > (GMAC) packet signing. Default: n/N/0"); > > to > > +MODULE_PARM_DESC(enable_negotiate_signing, "Enable negotiating packet > signing algorithm with server. Default: n/N/0"); > > I think it is ok to leave the GMAC comment to minimize the change in > the next patch (enabling GMAC) ... > > On Thu, Jul 8, 2021 at 6:19 PM Steve French wrote: > > > > It is a little tricky to figure out good wording here. > > > > "enable_negotiate_signing" (eventually) could end up requesting all 3 > > ... which means that the server could choose SHA256 over GMAC over > > CMAC. Maybe I should avoid all mention of GMAC. > > > > My reason for noting "GMAC is experimental" is that if GMAC is > > negotiated it is less tested than the other two (since fewer servers > > currently support it compared to the other two which are broadly > > supported and thus already tested with cifs.ko) - but the effect of > > the patch is to let the server choose which algorithm it prefers ... > > so perhaps I should avoid mentioning GMAC here. > > > > On Thu, Jul 8, 2021 at 5:06 PM Pavel Shilovsky wrote: > > > > > > @@ -104,6 +105,9 @@ MODULE_PARM_DESC(enable_gcm_256, "Enable > > > requesting strongest (256 bit) GCM encr > > > module_param(require_gcm_256, bool, 0644); > > > MODULE_PARM_DESC(require_gcm_256, "Require strongest (256 bit) GCM > > > encryption. Default: n/N/0"); > > > > > > +module_param(enable_negotiate_signing, bool, 0644); > > > +MODULE_PARM_DESC(enable_GMAC_signing, "Enable requesting faster > > > (GMAC) packet signing. Default: n/N/0"); > > > + > > > > > > s/enable_GMAC_signing/enable_negotiate_signing/ ? > > > > > > Also the description here is misleading: this param enables sending > > > the signing context not requesting GMAC which is not supported yet. > > > > > > > > > + if (enable_negotiate_signing) { > > > + pr_warn_once("requesting GMAC signing is experimental\n"); > > > > > > Here as well - we are not requesting GMAC here, we are sending the > > > signing context with CMAC. I don't think this should be marked as > > > experimental. > > > > > > -- > > > Best regards, > > > Pavel Shilovsky > > > > > > ср, 7 июл. 2021 г. в 21:52, ronnie sahlberg : > > > > > > > > lgtm > > > > > > > > On Thu, Jul 8, 2021 at 2:49 PM Steve French wrote: > > > > > > > > > > v4 of patch (includes minor change to set local variable "num_algs" > > > > > once to number of algorithms and use that throughout > > > > > build_signing_context to make code a little clearer) > > > > > > > > > > > > > > > On Wed, Jul 7, 2021 at 11:27 PM Steve French wrote: > > > > > > > > > > > > v3 of patch. Updated with additional feedback from Ronnie (to make it > > > > > > more context len and datalength clearer) > > > > > > > > > > > > > > > > > > On Wed, Jul 7, 2021 at 9:44 PM Steve French wrote: > > > > > > > > > > > > > > Support for faster packet signing (using GMAC instead of CMAC) can > > > > > > > now be negotiated to some newer servers, including Windows. > > > > > > > See MS-SMB2 section 2.2.3.17. > > > > > > > > > > > > > > This patch adds support for sending the new negotiate context > > > > > > > with the first of three supported signing algorithms (AES-CMAC) > > > > > > > and decoding the response. A followon patch will add support > > > > > > > for sending the other two (including AES-GMAC, which is fastest) > > > > > > > and changing the signing algorithm used based on what was > > > > > > > negotiated. > > > > > > > > > > > > > > To allow the client to request GMAC signing set module parameter > > > > > > > "enable_negotiate_signing" to 1. > > > > > > > > > > > > > > Reviewed-by: Ronnie Sahlberg > > > > > > > Signed-off-by: Steve French > > > > > > > --- > > > > > > > fs/cifs/cifsfs.c | 4 +++ > > > > > > > fs/cifs/cifsglob.h | 3 ++ > > > > > > > fs/cifs/smb2pdu.c | 83 ++++++++++++++++++++++++++++++++++++++++------ > > > > > > > fs/cifs/smb2pdu.h | 5 ++- > > > > > > > 4 files changed, 84 insertions(+), 11 deletions(-) > > > > > > > > > > > > > > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c > > > > > > > index 9fb874dd8d24..476b07213fcd 100644 > > > > > > > --- a/fs/cifs/cifsfs.c > > > > > > > +++ b/fs/cifs/cifsfs.c > > > > > > > @@ -65,6 +65,7 @@ bool lookupCacheEnabled = true; > > > > > > > bool disable_legacy_dialects; /* false by default */ > > > > > > > bool enable_gcm_256 = true; > > > > > > > bool require_gcm_256; /* false by default */ > > > > > > > +bool enable_negotiate_signing; /* false by default */ > > > > > > > unsigned int global_secflags = CIFSSEC_DEF; > > > > > > > /* unsigned int ntlmv2_support = 0; */ > > > > > > > unsigned int sign_CIFS_PDUs = 1; > > > > > > > @@ -104,6 +105,9 @@ MODULE_PARM_DESC(enable_gcm_256, "Enable > > > > > > > requesting strongest (256 bit) GCM encr > > > > > > > module_param(require_gcm_256, bool, 0644); > > > > > > > MODULE_PARM_DESC(require_gcm_256, "Require strongest (256 bit) GCM > > > > > > > encryption. Default: n/N/0"); > > > > > > > > > > > > > > +module_param(enable_negotiate_signing, bool, 0644); > > > > > > > +MODULE_PARM_DESC(enable_GMAC_signing, "Enable requesting faster > > > > > > > (GMAC) packet signing. Default: n/N/0"); > > > > > > > + > > > > > > > module_param(disable_legacy_dialects, bool, 0644); > > > > > > > MODULE_PARM_DESC(disable_legacy_dialects, "To improve security it may be " > > > > > > > "helpful to restrict the ability to " > > > > > > > diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h > > > > > > > index 921680fb7931..3c2e117bb926 100644 > > > > > > > --- a/fs/cifs/cifsglob.h > > > > > > > +++ b/fs/cifs/cifsglob.h > > > > > > > @@ -667,9 +667,11 @@ struct TCP_Server_Info { > > > > > > > unsigned int max_write; > > > > > > > unsigned int min_offload; > > > > > > > __le16 compress_algorithm; > > > > > > > + __u16 signing_algorithm; > > > > > > > __le16 cipher_type; > > > > > > > /* save initital negprot hash */ > > > > > > > __u8 preauth_sha_hash[SMB2_PREAUTH_HASH_SIZE]; > > > > > > > + bool signing_negotiated; /* true if valid signing context rcvd from server */ > > > > > > > bool posix_ext_supported; > > > > > > > struct delayed_work reconnect; /* reconnect workqueue job */ > > > > > > > struct mutex reconnect_mutex; /* prevent simultaneous reconnects */ > > > > > > > @@ -1869,6 +1871,7 @@ extern unsigned int global_secflags; /* if on, > > > > > > > session setup sent > > > > > > > extern unsigned int sign_CIFS_PDUs; /* enable smb packet signing */ > > > > > > > extern bool enable_gcm_256; /* allow optional negotiate of strongest > > > > > > > signing (aes-gcm-256) */ > > > > > > > extern bool require_gcm_256; /* require use of strongest signing > > > > > > > (aes-gcm-256) */ > > > > > > > +extern bool enable_negotiate_signing; /* request use of faster (GMAC) > > > > > > > signing if available */ > > > > > > > extern bool linuxExtEnabled;/*enable Linux/Unix CIFS extensions*/ > > > > > > > extern unsigned int CIFSMaxBufSize; /* max size not including hdr */ > > > > > > > extern unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */ > > > > > > > diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c > > > > > > > index 962826dc3316..757f145e70e5 100644 > > > > > > > --- a/fs/cifs/smb2pdu.c > > > > > > > +++ b/fs/cifs/smb2pdu.c > > > > > > > @@ -433,6 +433,23 @@ build_compression_ctxt(struct > > > > > > > smb2_compression_capabilities_context *pneg_ctxt) > > > > > > > pneg_ctxt->CompressionAlgorithms[2] = SMB3_COMPRESS_LZNT1; > > > > > > > } > > > > > > > > > > > > > > +static void > > > > > > > +build_signing_ctxt(struct smb2_signing_capabilities *pneg_ctxt) > > > > > > > +{ > > > > > > > + pneg_ctxt->ContextType = SMB2_SIGNING_CAPABILITIES; > > > > > > > + /* > > > > > > > + * Data length must be increased here if more than 3 signing algorithms > > > > > > > + * sent but currently only 3 are defined. And context Data length must > > > > > > > + * be rounded to multiple of 8 for some servers. > > > > > > > + */ > > > > > > > + pneg_ctxt->DataLength = > > > > > > > + cpu_to_le16(DIV_ROUND_UP(sizeof(struct smb2_signing_capabilities) - > > > > > > > + sizeof(struct smb2_neg_context), 8) * 8); > > > > > > > + pneg_ctxt->SigningAlgorithmCount = cpu_to_le16(1); > > > > > > > + pneg_ctxt->SigningAlgorithms[0] = cpu_to_le16(SIGNING_ALG_AES_CMAC); > > > > > > > + /* TBD add SIGNING_ALG_AES_GMAC and/or SIGNING_ALG_HMAC_SHA256 */ > > > > > > > +} > > > > > > > + > > > > > > > static void > > > > > > > build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt) > > > > > > > { > > > > > > > @@ -498,7 +515,7 @@ assemble_neg_contexts(struct smb2_negotiate_req *req, > > > > > > > struct TCP_Server_Info *server, unsigned int *total_len) > > > > > > > { > > > > > > > char *pneg_ctxt; > > > > > > > - unsigned int ctxt_len; > > > > > > > + unsigned int ctxt_len, neg_context_count; > > > > > > > > > > > > > > if (*total_len > 200) { > > > > > > > /* In case length corrupted don't want to overrun smb buffer */ > > > > > > > @@ -525,6 +542,17 @@ assemble_neg_contexts(struct smb2_negotiate_req *req, > > > > > > > *total_len += ctxt_len; > > > > > > > pneg_ctxt += ctxt_len; > > > > > > > > > > > > > > + ctxt_len = build_netname_ctxt((struct smb2_netname_neg_context *)pneg_ctxt, > > > > > > > + server->hostname); > > > > > > > + *total_len += ctxt_len; > > > > > > > + pneg_ctxt += ctxt_len; > > > > > > > + > > > > > > > + build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt); > > > > > > > + *total_len += sizeof(struct smb2_posix_neg_context); > > > > > > > + pneg_ctxt += sizeof(struct smb2_posix_neg_context); > > > > > > > + > > > > > > > + neg_context_count = 4; > > > > > > > + > > > > > > > if (server->compress_algorithm) { > > > > > > > build_compression_ctxt((struct smb2_compression_capabilities_context *) > > > > > > > pneg_ctxt); > > > > > > > @@ -533,17 +561,24 @@ assemble_neg_contexts(struct smb2_negotiate_req *req, > > > > > > > 8) * 8; > > > > > > > *total_len += ctxt_len; > > > > > > > pneg_ctxt += ctxt_len; > > > > > > > - req->NegotiateContextCount = cpu_to_le16(5); > > > > > > > - } else > > > > > > > - req->NegotiateContextCount = cpu_to_le16(4); > > > > > > > + neg_context_count++; > > > > > > > + } > > > > > > > > > > > > > > - ctxt_len = build_netname_ctxt((struct smb2_netname_neg_context *)pneg_ctxt, > > > > > > > - server->hostname); > > > > > > > - *total_len += ctxt_len; > > > > > > > - pneg_ctxt += ctxt_len; > > > > > > > + if (enable_negotiate_signing) { > > > > > > > + pr_warn_once("requesting GMAC signing is experimental\n"); > > > > > > > + build_signing_ctxt((struct smb2_signing_capabilities *) > > > > > > > + pneg_ctxt); > > > > > > > + ctxt_len = DIV_ROUND_UP( > > > > > > > + sizeof(struct smb2_signing_capabilities), > > > > > > > + 8) * 8; > > > > > > > + *total_len += ctxt_len; > > > > > > > + pneg_ctxt += ctxt_len; > > > > > > > + neg_context_count++; > > > > > > > + } > > > > > > > + > > > > > > > + /* check for and add transport_capabilities and signing capabilities */ > > > > > > > + req->NegotiateContextCount = cpu_to_le16(neg_context_count); > > > > > > > > > > > > > > - build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt); > > > > > > > - *total_len += sizeof(struct smb2_posix_neg_context); > > > > > > > } > > > > > > > > > > > > > > static void decode_preauth_context(struct smb2_preauth_neg_context *ctxt) > > > > > > > @@ -632,6 +667,31 @@ static int decode_encrypt_ctx(struct > > > > > > > TCP_Server_Info *server, > > > > > > > return 0; > > > > > > > } > > > > > > > > > > > > > > +static void decode_signing_ctx(struct TCP_Server_Info *server, > > > > > > > + struct smb2_signing_capabilities *pctxt) > > > > > > > +{ > > > > > > > + unsigned int len = le16_to_cpu(pctxt->DataLength); > > > > > > > + > > > > > > > + if ((len < 4) || (len > 16)) { > > > > > > > + pr_warn_once("server sent bad signing negcontext\n"); > > > > > > > + return; > > > > > > > + } > > > > > > > + if (le16_to_cpu(pctxt->SigningAlgorithmCount) != 1) { > > > > > > > + pr_warn_once("Invalid signing algorithm count\n"); > > > > > > > + return; > > > > > > > + } > > > > > > > + if (le16_to_cpu(pctxt->SigningAlgorithms[0]) > 2) { > > > > > > > + pr_warn_once("unknown signing algorithm\n"); > > > > > > > + return; > > > > > > > + } > > > > > > > + > > > > > > > + server->signing_negotiated = true; > > > > > > > + server->signing_algorithm = le16_to_cpu(pctxt->SigningAlgorithms[0]); > > > > > > > + cifs_dbg(FYI, "signing algorithm %d chosen\n", > > > > > > > + server->signing_algorithm); > > > > > > > +} > > > > > > > + > > > > > > > + > > > > > > > static int smb311_decode_neg_context(struct smb2_negotiate_rsp *rsp, > > > > > > > struct TCP_Server_Info *server, > > > > > > > unsigned int len_of_smb) > > > > > > > @@ -675,6 +735,9 @@ static int smb311_decode_neg_context(struct > > > > > > > smb2_negotiate_rsp *rsp, > > > > > > > (struct smb2_compression_capabilities_context *)pctx); > > > > > > > else if (pctx->ContextType == SMB2_POSIX_EXTENSIONS_AVAILABLE) > > > > > > > server->posix_ext_supported = true; > > > > > > > + else if (pctx->ContextType == SMB2_SIGNING_CAPABILITIES) > > > > > > > + decode_signing_ctx(server, > > > > > > > + (struct smb2_signing_capabilities *)pctx); > > > > > > > else > > > > > > > cifs_server_dbg(VFS, "unknown negcontext of type %d ignored\n", > > > > > > > le16_to_cpu(pctx->ContextType)); > > > > > > > diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h > > > > > > > index ba75e65924ac..4b27cb9105fd 100644 > > > > > > > --- a/fs/cifs/smb2pdu.h > > > > > > > +++ b/fs/cifs/smb2pdu.h > > > > > > > @@ -329,7 +329,7 @@ struct smb2_neg_context { > > > > > > > __le16 ContextType; > > > > > > > __le16 DataLength; > > > > > > > __le32 Reserved; > > > > > > > - /* Followed by array of data */ > > > > > > > + /* Followed by array of data. NOTE: some servers require padding to > > > > > > > 8 byte boundary */ > > > > > > > } __packed; > > > > > > > > > > > > > > #define SMB311_LINUX_CLIENT_SALT_SIZE 32 > > > > > > > @@ -394,6 +394,7 @@ struct smb2_compression_capabilities_context { > > > > > > > __u16 Padding; > > > > > > > __u32 Flags; > > > > > > > __le16 CompressionAlgorithms[3]; > > > > > > > + /* Check if pad needed */ > > > > > > > } __packed; > > > > > > > > > > > > > > /* > > > > > > > @@ -420,6 +421,7 @@ struct smb2_transport_capabilities_context { > > > > > > > __le16 DataLength; > > > > > > > __u32 Reserved; > > > > > > > __le32 Flags; > > > > > > > + __u32 Pad; > > > > > > > } __packed; > > > > > > > > > > > > > > /* > > > > > > > @@ -458,6 +460,7 @@ struct smb2_signing_capabilities { > > > > > > > __u32 Reserved; > > > > > > > __le16 SigningAlgorithmCount; > > > > > > > __le16 SigningAlgorithms[]; > > > > > > > + /* Followed by padding to 8 byte boundary (required by some servers) */ > > > > > > > } __packed; > > > > > > > > > > > > > > #define POSIX_CTXT_DATA_LEN 16 > > > > > > > > > > > > > > -- > > > > > > > Thanks, > > > > > > > > > > > > > > Steve > > > > > > > > > > > > > > > > > > > > > > > > -- > > > > > > Thanks, > > > > > > > > > > > > Steve > > > > > > > > > > > > > > > > > > > > -- > > > > > Thanks, > > > > > > > > > > Steve > > > > > > > > -- > > Thanks, > > > > Steve > > > > -- > Thanks, > > Steve -- Thanks, Steve