diff options
| author | Steve French <stfrench@microsoft.com> | 2020-09-12 00:19:28 +0300 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2020-10-16 07:58:15 +0300 |
| commit | fbfd0b46afa9a8b50a061b0f28204fc94c7bddcf (patch) | |
| tree | d1cff6f279fcaec234cd1dd133ed89003a7c3eea | |
| parent | 330857a5d8224fa073bcb88d78e5be51f0848a75 (diff) | |
| download | linux-fbfd0b46afa9a8b50a061b0f28204fc94c7bddcf.tar.xz | |
smb3.1.1: add new module load parm require_gcm_256
Add new module load parameter require_gcm_256. If set, then only
request AES-256-GCM (strongest encryption type).
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
| -rw-r--r-- | fs/cifs/cifsfs.c | 4 | ||||
| -rw-r--r-- | fs/cifs/cifsglob.h | 1 | ||||
| -rw-r--r-- | fs/cifs/smb2pdu.c | 14 |
3 files changed, 15 insertions, 4 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 0fb99d25e8a8..462dbbd17c5f 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 require_gcm_256; /* 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(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(require_gcm_256, bool, 0644); +MODULE_PARM_DESC(require_gcm_256, "Require strongest (256 bit) GCM encryption. 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 5a491afafacc..ec21af833749 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 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 */ 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 96c172d94fba..fcae1e3dfcc5 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -449,10 +449,16 @@ static void build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt) { pneg_ctxt->ContextType = SMB2_ENCRYPTION_CAPABILITIES; - pneg_ctxt->DataLength = cpu_to_le16(6); /* Cipher Count + two ciphers */ - pneg_ctxt->CipherCount = cpu_to_le16(2); - pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM; - pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES128_CCM; + if (require_gcm_256) { + 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 { + pneg_ctxt->DataLength = cpu_to_le16(6); /* Cipher Count + 2 ciphers */ + pneg_ctxt->CipherCount = cpu_to_le16(2); + pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM; + pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES128_CCM; + } } static unsigned int |