cifs: fix ntlmssp on old servers

Some older servers seem to require the workstation name during ntlmssp
to be at most 15 chars (RFC1001 name length), so truncate it before
sending when using insecure dialects.

Link: https://lore.kernel.org/r/e6837098-15d9-acb6-7e34-1923cf8c6fe1@winds.org
Reported-by: Byron Stanoszek <gandalf@winds.org>
Tested-by: Byron Stanoszek <gandalf@winds.org>
Fixes: 49bd49f983b5 ("cifs: send workstation name during ntlmssp session setup")
Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b6c2a787be06f1f6a7919c15dc7bfd6cc533ef31..68da230c7f11284ecb7444805e63c5ae4a24944e 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -952,7 +952,7 @@ struct cifs_ses {
                                   and after mount option parsing we fill it */
        char *domainName;
        char *password;
-       char *workstation_name;
+       char workstation_name[CIFS_MAX_WORKSTATION_LEN];
        struct session_key auth_key;
        struct ntlmssp_auth *ntlmssp; /* ciphertext, flags, server challenge */
        enum securityEnum sectype; /* what security flavor was specified? */
@@ -2018,4 +2018,17 @@ static inline u64 cifs_flock_len(struct file_lock *fl)
        return fl->fl_end == OFFSET_MAX ? 0 : fl->fl_end - fl->fl_start + 1;
 }
 
+static inline size_t ntlmssp_workstation_name_size(const struct cifs_ses *ses)
+{
+       if (WARN_ON_ONCE(!ses || !ses->server))
+               return 0;
+       /*
+        * Make workstation name no more than 15 chars when using insecure dialects as some legacy
+        * servers do require it during NTLMSSP.
+        */
+       if (ses->server->dialect <= SMB20_PROT_ID)
+               return min_t(size_t, sizeof(ses->workstation_name), RFC1001_NAME_LEN_WITH_NULL);
+       return sizeof(ses->workstation_name);
+}
+
 #endif /* _CIFS_GLOB_H */

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 199b076f7a6429b3071c41858bfc452f820a2221..53373a3649e17efbcb4e022a2685903108e12996 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2037,18 +2037,7 @@ cifs_set_cifscreds(struct smb3_fs_context *ctx, struct cifs_ses *ses)
                }
        }
 
-       ctx->workstation_name = kstrdup(ses->workstation_name, GFP_KERNEL);
-       if (!ctx->workstation_name) {
-               cifs_dbg(FYI, "Unable to allocate memory for workstation_name\n");
-               rc = -ENOMEM;
-               kfree(ctx->username);
-               ctx->username = NULL;
-               kfree_sensitive(ctx->password);
-               ctx->password = NULL;
-               kfree(ctx->domainname);
-               ctx->domainname = NULL;
-               goto out_key_put;
-       }
+       strscpy(ctx->workstation_name, ses->workstation_name, sizeof(ctx->workstation_name));
 
 out_key_put:
        up_read(&key->sem);
@@ -2157,12 +2146,9 @@ cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb3_fs_context *ctx)
                if (!ses->domainName)
                        goto get_ses_fail;
        }
-       if (ctx->workstation_name) {
-               ses->workstation_name = kstrdup(ctx->workstation_name,
-                                               GFP_KERNEL);
-               if (!ses->workstation_name)
-                       goto get_ses_fail;
-       }
+
+       strscpy(ses->workstation_name, ctx->workstation_name, sizeof(ses->workstation_name));
+
        if (ctx->domainauto)
                ses->domainAuto = ctx->domainauto;
        ses->cred_uid = ctx->cred_uid;

diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c
index ca1d6957a0999aa26d0b68009e64ce97bd753714..8dc0d923ef6a98bb279d883ee01f2b03b6ca2a1a 100644 (file)
--- a/fs/cifs/fs_context.c
+++ b/fs/cifs/fs_context.c
@@ -313,7 +313,6 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
        new_ctx->password = NULL;
        new_ctx->server_hostname = NULL;
        new_ctx->domainname = NULL;
-       new_ctx->workstation_name = NULL;
        new_ctx->UNC = NULL;
        new_ctx->source = NULL;
        new_ctx->iocharset = NULL;
@@ -328,7 +327,6 @@ smb3_fs_context_dup(struct smb3_fs_context *new_ctx, struct smb3_fs_context *ctx
        DUP_CTX_STR(UNC);
        DUP_CTX_STR(source);
        DUP_CTX_STR(domainname);
-       DUP_CTX_STR(workstation_name);
        DUP_CTX_STR(nodename);
        DUP_CTX_STR(iocharset);
 
@@ -767,8 +765,7 @@ static int smb3_verify_reconfigure_ctx(struct fs_context *fc,
                cifs_errorf(fc, "can not change domainname during remount\n");
                return -EINVAL;
        }
-       if (new_ctx->workstation_name &&
-           (!old_ctx->workstation_name || strcmp(new_ctx->workstation_name, old_ctx->workstation_name))) {
+       if (strcmp(new_ctx->workstation_name, old_ctx->workstation_name)) {
                cifs_errorf(fc, "can not change workstation_name during remount\n");
                return -EINVAL;
        }
@@ -815,7 +812,6 @@ static int smb3_reconfigure(struct fs_context *fc)
        STEAL_STRING(cifs_sb, ctx, username);
        STEAL_STRING(cifs_sb, ctx, password);
        STEAL_STRING(cifs_sb, ctx, domainname);
-       STEAL_STRING(cifs_sb, ctx, workstation_name);
        STEAL_STRING(cifs_sb, ctx, nodename);
        STEAL_STRING(cifs_sb, ctx, iocharset);
 
@@ -1471,22 +1467,15 @@ static int smb3_fs_context_parse_param(struct fs_context *fc,
 
 int smb3_init_fs_context(struct fs_context *fc)
 {
-       int rc;
        struct smb3_fs_context *ctx;
        char *nodename = utsname()->nodename;
        int i;
 
        ctx = kzalloc(sizeof(struct smb3_fs_context), GFP_KERNEL);
-       if (unlikely(!ctx)) {
-               rc = -ENOMEM;
-               goto err_exit;
-       }
+       if (unlikely(!ctx))
+               return -ENOMEM;
 
-       ctx->workstation_name = kstrdup(nodename, GFP_KERNEL);
-       if (unlikely(!ctx->workstation_name)) {
-               rc = -ENOMEM;
-               goto err_exit;
-       }
+       strscpy(ctx->workstation_name, nodename, sizeof(ctx->workstation_name));
 
        /*
         * does not have to be perfect mapping since field is
@@ -1559,14 +1548,6 @@ int smb3_init_fs_context(struct fs_context *fc)
        fc->fs_private = ctx;
        fc->ops = &smb3_fs_context_ops;
        return 0;
-
-err_exit:
-       if (ctx) {
-               kfree(ctx->workstation_name);
-               kfree(ctx);
-       }
-
-       return rc;
 }
 
 void
@@ -1592,8 +1573,6 @@ smb3_cleanup_fs_context_contents(struct smb3_fs_context *ctx)
        ctx->source = NULL;
        kfree(ctx->domainname);
        ctx->domainname = NULL;
-       kfree(ctx->workstation_name);
-       ctx->workstation_name = NULL;
        kfree(ctx->nodename);
        ctx->nodename = NULL;
        kfree(ctx->iocharset);

diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index 6576bb12f5f10ff7fd2c654f2870f5c295a4662b..5f093cb7e9b98ef791de8c01857c7f4136bbe9c5 100644 (file)
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -171,7 +171,7 @@ struct smb3_fs_context {
        char *server_hostname;
        char *UNC;
        char *nodename;
-       char *workstation_name;
+       char workstation_name[CIFS_MAX_WORKSTATION_LEN];
        char *iocharset;  /* local code page for mapping to and from Unicode */
        char source_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* clnt nb name */
        char target_rfc1001_name[RFC1001_NAME_LEN_WITH_NULL]; /* srvr nb name */

diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index af5e68a778110cae83a86e4fbbb2a34962c5eb78..35962a1a23b90f3775e58f3a642fe7a647253205 100644 (file)
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -95,7 +95,6 @@ sesInfoFree(struct cifs_ses *buf_to_free)
        kfree_sensitive(buf_to_free->password);
        kfree(buf_to_free->user_name);
        kfree(buf_to_free->domainName);
-       kfree(buf_to_free->workstation_name);
        kfree_sensitive(buf_to_free->auth_key.response);
        kfree(buf_to_free->iface_list);
        kfree_sensitive(buf_to_free);

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 7c453f8701eb0f543925f66a0755f65bf7ad1b5b..c6214cfc575f3b1cd38e322e34ef04a7829591e5 100644 (file)
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -741,9 +741,9 @@ static int size_of_ntlmssp_blob(struct cifs_ses *ses, int base_size)
        else
                sz += sizeof(__le16);
 
-       if (ses->workstation_name)
+       if (ses->workstation_name[0])
                sz += sizeof(__le16) * strnlen(ses->workstation_name,
-                       CIFS_MAX_WORKSTATION_LEN);
+                                              ntlmssp_workstation_name_size(ses));
        else
                sz += sizeof(__le16);
 
@@ -987,7 +987,7 @@ int build_ntlmssp_auth_blob(unsigned char **pbuffer,
 
        cifs_security_buffer_from_str(&sec_blob->WorkstationName,
                                      ses->workstation_name,
-                                     CIFS_MAX_WORKSTATION_LEN,
+                                     ntlmssp_workstation_name_size(ses),
                                      *pbuffer, &tmp,
                                      nls_cp);