[CIFS] SMB3 Signing enablement

SMB3 uses a much faster method of signing (which is also better in other ways),
AES-CMAC.  With the kernel now supporting AES-CMAC since last release, we
are overdue to allow SMB3 signing (today only CIFS and SMB2 and SMB2.1,
but not SMB3 and SMB3.1 can sign) - and we need this also for checking
secure negotation and also per-share encryption (two other new SMB3 features
which we need to implement).

This patch needs some work in a few areas - for example we need to
move signing for SMB2/SMB3 from per-socket to per-user (we may be able to
use the "nosharesock" mount option in the interim for the multiuser case),
and Shirish found a bug in the earlier authentication overhaul
(setting signing flags properly) - but those can be done in followon
patches.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 330875948f18..3d8bf941d126 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -705,6 +705,9 @@ calc_seckey(struct cifs_ses *ses)
 void
 cifs_crypto_shash_release(struct TCP_Server_Info *server)
 {
+        if (server->secmech.cmacaes)
+                crypto_free_shash(server->secmech.cmacaes);
+
         if (server->secmech.hmacsha256)
                 crypto_free_shash(server->secmech.hmacsha256);
 
@@ -714,6 +717,8 @@ cifs_crypto_shash_release(struct TCP_Server_Info *server)
         if (server->secmech.hmacmd5)
                 crypto_free_shash(server->secmech.hmacmd5);
 
+        kfree(server->secmech.sdesccmacaes);
+
         kfree(server->secmech.sdeschmacsha256);
 
         kfree(server->secmech.sdeschmacmd5);
@@ -747,6 +752,13 @@ cifs_crypto_shash_allocate(struct TCP_Server_Info *server)
                 goto crypto_allocate_hmacsha256_fail;
         }
 
+        server->secmech.cmacaes = crypto_alloc_shash("cmac(aes)", 0, 0);
+        if (IS_ERR(server->secmech.cmacaes)) {
+                cifs_dbg(VFS, "could not allocate crypto cmac-aes");
+                rc = PTR_ERR(server->secmech.cmacaes);
+                goto crypto_allocate_cmacaes_fail;
+        }
+
         size = sizeof(struct shash_desc) +
                         crypto_shash_descsize(server->secmech.hmacmd5);
         server->secmech.sdeschmacmd5 = kmalloc(size, GFP_KERNEL);
@@ -777,8 +789,22 @@ cifs_crypto_shash_allocate(struct TCP_Server_Info *server)
         server->secmech.sdeschmacsha256->shash.tfm = server->secmech.hmacsha256;
         server->secmech.sdeschmacsha256->shash.flags = 0x0;
 
+        size = sizeof(struct shash_desc) +
+                        crypto_shash_descsize(server->secmech.cmacaes);
+        server->secmech.sdesccmacaes = kmalloc(size, GFP_KERNEL);
+        if (!server->secmech.sdesccmacaes) {
+                cifs_dbg(VFS, "%s: Can't alloc cmacaes\n", __func__);
+                rc = -ENOMEM;
+                goto crypto_allocate_cmacaes_sdesc_fail;
+        }
+        server->secmech.sdesccmacaes->shash.tfm = server->secmech.cmacaes;
+        server->secmech.sdesccmacaes->shash.flags = 0x0;
+
         return 0;
 
+crypto_allocate_cmacaes_sdesc_fail:
+        kfree(server->secmech.sdeschmacsha256);
+
 crypto_allocate_hmacsha256_sdesc_fail:
         kfree(server->secmech.sdescmd5);
 
@@ -786,6 +812,9 @@ crypto_allocate_md5_sdesc_fail:
         kfree(server->secmech.sdeschmacmd5);
 
 crypto_allocate_hmacmd5_sdesc_fail:
+        crypto_free_shash(server->secmech.cmacaes);
+
+crypto_allocate_cmacaes_fail:
         crypto_free_shash(server->secmech.hmacsha256);
 
 crypto_allocate_hmacsha256_fail: