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authorSteve French <stfrench@microsoft.com>2018-06-19 22:34:08 +0300
committerSteve French <stfrench@microsoft.com>2018-08-07 22:15:41 +0300
commit7420451f6a109f7f8f1bf283f34d08eba3259fb3 (patch)
treecdaf7f33cae4b08c32c6d6baae5dfa0dcfe32121 /fs/cifs
parent8505c8bfd85a260c9dc5c47e15bd8c5357fcbcd2 (diff)
downloadlinux-7420451f6a109f7f8f1bf283f34d08eba3259fb3.tar.xz
cifs: allow disabling insecure dialects in the config
allow disabling cifs (SMB1 ie vers=1.0) and vers=2.0 in the config for the build of cifs.ko if want to always prevent mounting with these less secure dialects. Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Aurelien Aptel <aaptel@suse.com> Reviewed-by: Jeremy Allison <jra@samba.org>
Diffstat (limited to 'fs/cifs')
-rw-r--r--fs/cifs/Kconfig17
-rw-r--r--fs/cifs/connect.c9
2 files changed, 25 insertions, 1 deletions
diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index 5f132d59dfc2..832eafbf803f 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -66,9 +66,24 @@ config CIFS_STATS2
Unless you are a developer or are doing network performance analysis
or tuning, say N.
+config CIFS_ALLOW_INSECURE_LEGACY
+ bool "Support legacy servers which use less secure dialects"
+ depends on CIFS
+ default y
+ help
+ Modern dialects, SMB2.1 and later (including SMB3 and 3.1.1), have
+ additional security features, including protection against
+ man-in-the-middle attacks and stronger crypto hashes, so the use
+ of legacy dialects (SMB1/CIFS and SMB2.0) is discouraged.
+
+ Disabling this option prevents users from using vers=1.0 or vers=2.0
+ on mounts with cifs.ko
+
+ If unsure, say Y.
+
config CIFS_WEAK_PW_HASH
bool "Support legacy servers which use weaker LANMAN security"
- depends on CIFS
+ depends on CIFS && CIFS_ALLOW_INSECURE_LEGACY
help
Modern CIFS servers including Samba and most Windows versions
(since 1997) support stronger NTLM (and even NTLMv2 and Kerberos)
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 9d02563b2147..842f45859968 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1174,6 +1174,7 @@ cifs_parse_smb_version(char *value, struct smb_vol *vol, bool is_smb3)
substring_t args[MAX_OPT_ARGS];
switch (match_token(value, cifs_smb_version_tokens, args)) {
+#ifdef CONFIG_CIFS_ALLOW_INSECURE_LEGACY
case Smb_1:
if (disable_legacy_dialects) {
cifs_dbg(VFS, "mount with legacy dialect disabled\n");
@@ -1198,6 +1199,14 @@ cifs_parse_smb_version(char *value, struct smb_vol *vol, bool is_smb3)
vol->ops = &smb20_operations;
vol->vals = &smb20_values;
break;
+#else
+ case Smb_1:
+ cifs_dbg(VFS, "vers=1.0 (cifs) mount not permitted when legacy dialects disabled\n");
+ return 1;
+ case Smb_20:
+ cifs_dbg(VFS, "vers=2.0 mount not permitted when legacy dialects disabled\n");
+ return 1;
+#endif /* CIFS_ALLOW_INSECURE_LEGACY */
case Smb_21:
vol->ops = &smb21_operations;
vol->vals = &smb21_values;