diff options
| author | Steve French <stfrench@microsoft.com> | 2020-10-14 20:24:09 -0500 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2020-10-15 23:58:15 -0500 |
| commit | 29e279230413cdd5e00fb5d269cae1099184ab85 (patch) | |
| tree | 8556337d076697bdbaba24dc949bdf2f33b3d179 /fs/cifs | |
| parent | fbfd0b46afa9a8b50a061b0f28204fc94c7bddcf (diff) | |
smb3.1.1: add new module load parm enable_gcm_256
Add new module load parameter enable_gcm_256. If set, then add
AES-256-GCM (strongest encryption type) to the list of encryption
types requested. Put it in the list as the second choice (since
AES-128-GCM is faster and much more broadly supported by
SMB3 servers). To make this stronger encryption type, GCM-256,
required (the first and only choice, you would use module parameter
"require_gcm_256."
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/cifs')
| -rw-r--r-- | fs/cifs/cifsfs.c | 4 | ||||
| -rw-r--r-- | fs/cifs/cifsglob.h | 1 | ||||
| -rw-r--r-- | fs/cifs/smb2pdu.c | 6 | ||||
| -rw-r--r-- | fs/cifs/smb2pdu.h | 5 |
4 files changed, 14 insertions, 2 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 462dbbd17c5f..472cb7777e3e 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -71,6 +71,7 @@ bool enable_oplocks = true; bool linuxExtEnabled = true; bool lookupCacheEnabled = true; bool disable_legacy_dialects; /* false by default */ +bool enable_gcm_256; /* false by default, change when more servers support it */ bool require_gcm_256; /* false by default */ unsigned int global_secflags = CIFSSEC_DEF; /* unsigned int ntlmv2_support = 0; */ @@ -105,6 +106,9 @@ MODULE_PARM_DESC(slow_rsp_threshold, "Amount of time (in seconds) to wait " module_param(enable_oplocks, bool, 0644); MODULE_PARM_DESC(enable_oplocks, "Enable or disable oplocks. Default: y/Y/1"); +module_param(enable_gcm_256, bool, 0644); +MODULE_PARM_DESC(enable_gcm_256, "Enable requesting strongest (256 bit) GCM encryption. Default: n/N/0"); + module_param(require_gcm_256, bool, 0644); MODULE_PARM_DESC(require_gcm_256, "Require strongest (256 bit) GCM encryption. Default: n/N/0"); diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h index ec21af833749..a1a1a16acb38 100644 --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -1956,6 +1956,7 @@ extern bool lookupCacheEnabled; extern unsigned int global_secflags; /* if on, session setup sent with more secure ntlmssp2 challenge/resp */ 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 linuxExtEnabled;/*enable Linux/Unix CIFS extensions*/ extern unsigned int CIFSMaxBufSize; /* max size not including hdr */ diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index fcae1e3dfcc5..8cfc3122ae5c 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -453,6 +453,12 @@ build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt) pneg_ctxt->DataLength = cpu_to_le16(4); /* Cipher Count + 1 cipher */ pneg_ctxt->CipherCount = cpu_to_le16(1); pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES256_GCM; + } else if (enable_gcm_256) { + pneg_ctxt->DataLength = cpu_to_le16(8); /* Cipher Count + 3 ciphers */ + pneg_ctxt->CipherCount = cpu_to_le16(3); + pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM; + pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES256_GCM; + pneg_ctxt->Ciphers[2] = SMB2_ENCRYPTION_AES128_CCM; } else { pneg_ctxt->DataLength = cpu_to_le16(6); /* Cipher Count + 2 ciphers */ pneg_ctxt->CipherCount = cpu_to_le16(2); diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h index 5932fc0dc62c..6f65f1cec8ad 100644 --- a/fs/cifs/smb2pdu.h +++ b/fs/cifs/smb2pdu.h @@ -361,8 +361,9 @@ struct smb2_encryption_neg_context { __le16 ContextType; /* 2 */ __le16 DataLength; __le32 Reserved; - __le16 CipherCount; /* AES-128-GCM and AES-128-CCM */ - __le16 Ciphers[2]; + /* CipherCount usally 2, but can be 3 when AES256-GCM enabled */ + __le16 CipherCount; /* AES128-GCM and AES128-CCM by default */ + __le16 Ciphers[3]; } __packed; /* See MS-SMB2 2.2.3.1.3 */ |