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-rw-r--r--fs/cifs/cifsfs.c10
-rw-r--r--fs/cifs/cifsglob.h19
-rw-r--r--fs/cifs/connect.c9
3 files changed, 29 insertions, 9 deletions
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index fe30aabe00d7..c608ea62f536 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -58,6 +58,7 @@ bool traceSMB;
bool enable_oplocks = true;
bool linuxExtEnabled = true;
bool lookupCacheEnabled = true;
+bool disable_legacy_dialects; /* false by default */
unsigned int global_secflags = CIFSSEC_DEF;
/* unsigned int ntlmv2_support = 0; */
unsigned int sign_CIFS_PDUs = 1;
@@ -83,6 +84,15 @@ MODULE_PARM_DESC(cifs_max_pending, "Simultaneous requests to server for "
module_param(enable_oplocks, bool, 0644);
MODULE_PARM_DESC(enable_oplocks, "Enable or disable oplocks. Default: y/Y/1");
+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 "
+ "override the default dialects (SMB2.1, "
+ "SMB3 and SMB3.02) on mount with old "
+ "dialects (CIFS/SMB1 and SMB2) since "
+ "vers=1.0 (CIFS/SMB1) and vers=2.0 are weaker"
+ " and less secure. Default: n/N/0");
+
extern mempool_t *cifs_sm_req_poolp;
extern mempool_t *cifs_req_poolp;
extern mempool_t *cifs_mid_poolp;
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index d8c8700454ed..d2ac9ced28c9 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1700,16 +1700,17 @@ GLOBAL_EXTERN atomic_t smBufAllocCount;
GLOBAL_EXTERN atomic_t midCount;
/* Misc globals */
-GLOBAL_EXTERN bool enable_oplocks; /* enable or disable oplocks */
-GLOBAL_EXTERN bool lookupCacheEnabled;
-GLOBAL_EXTERN unsigned int global_secflags; /* if on, session setup sent
+extern bool enable_oplocks; /* enable or disable oplocks */
+extern bool lookupCacheEnabled;
+extern unsigned int global_secflags; /* if on, session setup sent
with more secure ntlmssp2 challenge/resp */
-GLOBAL_EXTERN unsigned int sign_CIFS_PDUs; /* enable smb packet signing */
-GLOBAL_EXTERN bool linuxExtEnabled;/*enable Linux/Unix CIFS extensions*/
-GLOBAL_EXTERN unsigned int CIFSMaxBufSize; /* max size not including hdr */
-GLOBAL_EXTERN unsigned int cifs_min_rcv; /* min size of big ntwrk buf pool */
-GLOBAL_EXTERN unsigned int cifs_min_small; /* min size of small buf pool */
-GLOBAL_EXTERN unsigned int cifs_max_pending; /* MAX requests at once to server*/
+extern unsigned int sign_CIFS_PDUs; /* enable smb packet signing */
+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 */
+extern unsigned int cifs_min_small; /* min size of small buf pool */
+extern unsigned int cifs_max_pending; /* MAX requests at once to server*/
+extern bool disable_legacy_dialects; /* forbid vers=1.0 and vers=2.0 mounts */
#ifdef CONFIG_CIFS_ACL
GLOBAL_EXTERN struct rb_root uidtree;
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 83b0234d443c..ed3b6de88395 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -61,6 +61,7 @@
#define RFC1001_PORT 139
extern mempool_t *cifs_req_poolp;
+extern bool disable_legacy_dialects;
/* FIXME: should these be tunable? */
#define TLINK_ERROR_EXPIRE (1 * HZ)
@@ -1146,10 +1147,18 @@ cifs_parse_smb_version(char *value, struct smb_vol *vol)
switch (match_token(value, cifs_smb_version_tokens, args)) {
case Smb_1:
+ if (disable_legacy_dialects) {
+ cifs_dbg(VFS, "mount with legacy dialect disabled\n");
+ return 1;
+ }
vol->ops = &smb1_operations;
vol->vals = &smb1_values;
break;
case Smb_20:
+ if (disable_legacy_dialects) {
+ cifs_dbg(VFS, "mount with legacy dialect disabled\n");
+ return 1;
+ }
vol->ops = &smb20_operations;
vol->vals = &smb20_values;
break;