CIFS: Encrypt SMB3 requests before sending

This change allows to encrypt packets if it is required by a server
for SMB sessions or tree connections.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>

10 files changed, 320 insertions, 10 deletions

diff --git a/fs/cifs/Kconfig b/fs/cifs/Kconfig
index ff0d1fe542f7..034f00f21390 100644
--- a/fs/cifs/Kconfig
+++ b/fs/cifs/Kconfig
@@ -174,6 +174,8 @@ config CIFS_SMB2
         select CRYPTO_AES
         select CRYPTO_SHA256
         select CRYPTO_CMAC
+        select CRYPTO_AEAD2
+        select CRYPTO_CCM
 
         help
           This enables support for the Server Message Block version 2
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index d8af15f19dd8..058ac9b36f04 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -34,6 +34,7 @@
 #include <linux/random.h>
 #include <linux/highmem.h>
 #include <crypto/skcipher.h>
+#include <crypto/aead.h>
 
 static int
 cifs_crypto_shash_md5_allocate(struct TCP_Server_Info *server)
@@ -874,7 +875,7 @@ out:
 }
 
 void
-cifs_crypto_shash_release(struct TCP_Server_Info *server)
+cifs_crypto_secmech_release(struct TCP_Server_Info *server)
 {
         if (server->secmech.cmacaes) {
                 crypto_free_shash(server->secmech.cmacaes);
@@ -896,6 +897,16 @@ cifs_crypto_shash_release(struct TCP_Server_Info *server)
                 server->secmech.hmacmd5 = NULL;
         }
 
+        if (server->secmech.ccmaesencrypt) {
+                crypto_free_aead(server->secmech.ccmaesencrypt);
+                server->secmech.ccmaesencrypt = NULL;
+        }
+
+        if (server->secmech.ccmaesdecrypt) {
+                crypto_free_aead(server->secmech.ccmaesdecrypt);
+                server->secmech.ccmaesdecrypt = NULL;
+        }
+
         kfree(server->secmech.sdesccmacaes);
         server->secmech.sdesccmacaes = NULL;
         kfree(server->secmech.sdeschmacsha256);
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 956dd85d7aef..15e1db8738ae 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1376,6 +1376,8 @@ MODULE_SOFTDEP("pre: nls");
 MODULE_SOFTDEP("pre: aes");
 MODULE_SOFTDEP("pre: cmac");
 MODULE_SOFTDEP("pre: sha256");
+MODULE_SOFTDEP("pre: aead2");
+MODULE_SOFTDEP("pre: ccm");
 #endif /* CONFIG_CIFS_SMB2 */
 module_init(init_cifs)
 module_exit(exit_cifs)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index ff7114d27a69..14196e00f79e 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -136,6 +136,8 @@ struct cifs_secmech {
         struct sdesc *sdescmd5; /* ctxt to generate cifs/smb signature */
         struct sdesc *sdeschmacsha256;  /* ctxt to generate smb2 signature */
         struct sdesc *sdesccmacaes;  /* ctxt to generate smb3 signature */
+        struct crypto_aead *ccmaesencrypt; /* smb3 encryption aead */
+        struct crypto_aead *ccmaesdecrypt; /* smb3 decryption aead */
 };
 
 /* per smb session structure/fields */
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 711718cd73dd..26872f54ca3f 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -445,7 +445,7 @@ extern int SMBNTencrypt(unsigned char *, unsigned char *, unsigned char *,
                         const struct nls_table *);
 extern int setup_ntlm_response(struct cifs_ses *, const struct nls_table *);
 extern int setup_ntlmv2_rsp(struct cifs_ses *, const struct nls_table *);
-extern void cifs_crypto_shash_release(struct TCP_Server_Info *);
+extern void cifs_crypto_secmech_release(struct TCP_Server_Info *server);
 extern int calc_seckey(struct cifs_ses *);
 extern int generate_smb30signingkey(struct cifs_ses *);
 extern int generate_smb311signingkey(struct cifs_ses *);
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 35ae49ed1f76..b84febf960e9 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2154,7 +2154,7 @@ cifs_put_tcp_session(struct TCP_Server_Info *server, int from_reconnect)
         server->tcpStatus = CifsExiting;
         spin_unlock(&GlobalMid_Lock);
 
-        cifs_crypto_shash_release(server);
+        cifs_crypto_secmech_release(server);
         cifs_fscache_release_client_cookie(server);
 
         kfree(server->session_key.response);
@@ -2273,7 +2273,7 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
         return tcp_ses;
 
 out_err_crypto_release:
-        cifs_crypto_shash_release(tcp_ses);
+        cifs_crypto_secmech_release(tcp_ses);
 
         put_net(cifs_net_ns(tcp_ses));
 
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index ef8b2a8363b3..54b49358eaaf 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -20,6 +20,8 @@
 #include <linux/pagemap.h>
 #include <linux/vfs.h>
 #include <linux/falloc.h>
+#include <linux/scatterlist.h>
+#include <crypto/aead.h>
 #include "cifsglob.h"
 #include "smb2pdu.h"
 #include "smb2proto.h"
@@ -1547,6 +1549,256 @@ smb2_dir_needs_close(struct cifsFileInfo *cfile)
         return !cfile->invalidHandle;
 }
 
+static void
+fill_transform_hdr(struct smb2_transform_hdr *tr_hdr, struct smb_rqst *old_rq)
+{
+        struct smb2_sync_hdr *shdr =
+                        (struct smb2_sync_hdr *)old_rq->rq_iov[1].iov_base;
+        unsigned int orig_len = get_rfc1002_length(old_rq->rq_iov[0].iov_base);
+
+        memset(tr_hdr, 0, sizeof(struct smb2_transform_hdr));
+        tr_hdr->ProtocolId = SMB2_TRANSFORM_PROTO_NUM;
+        tr_hdr->OriginalMessageSize = cpu_to_le32(orig_len);
+        tr_hdr->Flags = cpu_to_le16(0x01);
+        get_random_bytes(&tr_hdr->Nonce, SMB3_AES128CMM_NONCE);
+        memcpy(&tr_hdr->SessionId, &shdr->SessionId, 8);
+        inc_rfc1001_len(tr_hdr, sizeof(struct smb2_transform_hdr) - 4);
+        inc_rfc1001_len(tr_hdr, orig_len);
+}
+
+static struct scatterlist *
+init_sg(struct smb_rqst *rqst, u8 *sign)
+{
+        unsigned int sg_len = rqst->rq_nvec + rqst->rq_npages + 1;
+        unsigned int assoc_data_len = sizeof(struct smb2_transform_hdr) - 24;
+        struct scatterlist *sg;
+        unsigned int i;
+        unsigned int j;
+
+        sg = kmalloc_array(sg_len, sizeof(struct scatterlist), GFP_KERNEL);
+        if (!sg)
+                return NULL;
+
+        sg_init_table(sg, sg_len);
+        sg_set_buf(&sg[0], rqst->rq_iov[0].iov_base + 24, assoc_data_len);
+        for (i = 1; i < rqst->rq_nvec; i++)
+                sg_set_buf(&sg[i], rqst->rq_iov[i].iov_base,
+                                                rqst->rq_iov[i].iov_len);
+        for (j = 0; i < sg_len - 1; i++, j++) {
+                unsigned int len = (j < rqst->rq_npages - 1) ? rqst->rq_pagesz
+                                                        : rqst->rq_tailsz;
+                sg_set_page(&sg[i], rqst->rq_pages[j], len, 0);
+        }
+        sg_set_buf(&sg[sg_len - 1], sign, SMB2_SIGNATURE_SIZE);
+        return sg;
+}
+
+struct cifs_crypt_result {
+        int err;
+        struct completion completion;
+};
+
+static void cifs_crypt_complete(struct crypto_async_request *req, int err)
+{
+        struct cifs_crypt_result *res = req->data;
+
+        if (err == -EINPROGRESS)
+                return;
+
+        res->err = err;
+        complete(&res->completion);
+}
+
+/*
+ * Encrypt or decrypt @rqst message. @rqst has the following format:
+ * iov[0] - transform header (associate data),
+ * iov[1-N] and pages - data to encrypt.
+ * On success return encrypted data in iov[1-N] and pages, leave iov[0]
+ * untouched.
+ */
+static int
+crypt_message(struct TCP_Server_Info *server, struct smb_rqst *rqst, int enc)
+{
+        struct smb2_transform_hdr *tr_hdr =
+                        (struct smb2_transform_hdr *)rqst->rq_iov[0].iov_base;
+        unsigned int assoc_data_len = sizeof(struct smb2_transform_hdr) - 24;
+        struct cifs_ses *ses;
+        int rc = 0;
+        struct scatterlist *sg;
+        u8 sign[SMB2_SIGNATURE_SIZE] = {};
+        struct aead_request *req;
+        char *iv;
+        unsigned int iv_len;
+        struct cifs_crypt_result result = {0, };
+        struct crypto_aead *tfm;
+        unsigned int crypt_len = le32_to_cpu(tr_hdr->OriginalMessageSize);
+
+        init_completion(&result.completion);
+
+        ses = smb2_find_smb_ses(server, tr_hdr->SessionId);
+        if (!ses) {
+                cifs_dbg(VFS, "%s: Could not find session\n", __func__);
+                return 0;
+        }
+
+        rc = smb3_crypto_aead_allocate(server);
+        if (rc) {
+                cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
+                return rc;
+        }
+
+        tfm = enc ? server->secmech.ccmaesencrypt :
+                                                server->secmech.ccmaesdecrypt;
+        rc = crypto_aead_setkey(tfm, enc ? ses->smb3encryptionkey :
+                                ses->smb3decryptionkey, SMB3_SIGN_KEY_SIZE);
+        if (rc) {
+                cifs_dbg(VFS, "%s: Failed to set aead key %d\n", __func__, rc);
+                return rc;
+        }
+
+        rc = crypto_aead_setauthsize(tfm, SMB2_SIGNATURE_SIZE);
+        if (rc) {
+                cifs_dbg(VFS, "%s: Failed to set authsize %d\n", __func__, rc);
+                return rc;
+        }
+
+        req = aead_request_alloc(tfm, GFP_KERNEL);
+        if (!req) {
+                cifs_dbg(VFS, "%s: Failed to alloc aead request", __func__);
+                return -ENOMEM;
+        }
+
+        if (!enc) {
+                memcpy(sign, &tr_hdr->Signature, SMB2_SIGNATURE_SIZE);
+                crypt_len += SMB2_SIGNATURE_SIZE;
+        }
+
+        sg = init_sg(rqst, sign);
+        if (!sg) {
+                cifs_dbg(VFS, "%s: Failed to init sg %d", __func__, rc);
+                goto free_req;
+        }
+
+        iv_len = crypto_aead_ivsize(tfm);
+        iv = kzalloc(iv_len, GFP_KERNEL);
+        if (!iv) {
+                cifs_dbg(VFS, "%s: Failed to alloc IV", __func__);
+                goto free_sg;
+        }
+        iv[0] = 3;
+        memcpy(iv + 1, (char *)tr_hdr->Nonce, SMB3_AES128CMM_NONCE);
+
+        aead_request_set_crypt(req, sg, sg, crypt_len, iv);
+        aead_request_set_ad(req, assoc_data_len);
+
+        aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
+                                  cifs_crypt_complete, &result);
+
+        rc = enc ? crypto_aead_encrypt(req) : crypto_aead_decrypt(req);
+
+        if (rc == -EINPROGRESS || rc == -EBUSY) {
+                wait_for_completion(&result.completion);
+                rc = result.err;
+        }
+
+        if (!rc && enc)
+                memcpy(&tr_hdr->Signature, sign, SMB2_SIGNATURE_SIZE);
+
+        kfree(iv);
+free_sg:
+        kfree(sg);
+free_req:
+        kfree(req);
+        return rc;
+}
+
+static int
+smb3_init_transform_rq(struct TCP_Server_Info *server, struct smb_rqst *new_rq,
+                       struct smb_rqst *old_rq)
+{
+        struct kvec *iov;
+        struct page **pages;
+        struct smb2_transform_hdr *tr_hdr;
+        unsigned int npages = old_rq->rq_npages;
+        int i;
+        int rc = -ENOMEM;
+
+        pages = kmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
+        if (!pages)
+                return rc;
+
+        new_rq->rq_pages = pages;
+        new_rq->rq_npages = old_rq->rq_npages;
+        new_rq->rq_pagesz = old_rq->rq_pagesz;
+        new_rq->rq_tailsz = old_rq->rq_tailsz;
+
+        for (i = 0; i < npages; i++) {
+                pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
+                if (!pages[i])
+                        goto err_free_pages;
+        }
+
+        iov = kmalloc_array(old_rq->rq_nvec, sizeof(struct kvec), GFP_KERNEL);
+        if (!iov)
+                goto err_free_pages;
+
+        /* copy all iovs from the old except the 1st one (rfc1002 length) */
+        memcpy(&iov[1], &old_rq->rq_iov[1],
+                                sizeof(struct kvec) * (old_rq->rq_nvec - 1));
+        new_rq->rq_iov = iov;
+        new_rq->rq_nvec = old_rq->rq_nvec;
+
+        tr_hdr = kmalloc(sizeof(struct smb2_transform_hdr), GFP_KERNEL);
+        if (!tr_hdr)
+                goto err_free_iov;
+
+        /* fill the 1st iov with a transform header */
+        fill_transform_hdr(tr_hdr, old_rq);
+        new_rq->rq_iov[0].iov_base = tr_hdr;
+        new_rq->rq_iov[0].iov_len = sizeof(struct smb2_transform_hdr);
+
+        /* copy pages form the old */
+        for (i = 0; i < npages; i++) {
+                char *dst = kmap(new_rq->rq_pages[i]);
+                char *src = kmap(old_rq->rq_pages[i]);
+                unsigned int len = (i < npages - 1) ? new_rq->rq_pagesz :
+                                                        new_rq->rq_tailsz;
+                memcpy(dst, src, len);
+                kunmap(new_rq->rq_pages[i]);
+                kunmap(old_rq->rq_pages[i]);
+        }
+
+        rc = crypt_message(server, new_rq, 1);
+        cifs_dbg(FYI, "encrypt message returned %d", rc);
+        if (rc)
+                goto err_free_tr_hdr;
+
+        return rc;
+
+err_free_tr_hdr:
+        kfree(tr_hdr);
+err_free_iov:
+        kfree(iov);
+err_free_pages:
+        for (i = i - 1; i >= 0; i--)
+                put_page(pages[i]);
+        kfree(pages);
+        return rc;
+}
+
+static void
+smb3_free_transform_rq(struct smb_rqst *rqst)
+{
+        int i = rqst->rq_npages - 1;
+
+        for (; i >= 0; i--)
+                put_page(rqst->rq_pages[i]);
+        kfree(rqst->rq_pages);
+        /* free transform header */
+        kfree(rqst->rq_iov[0].iov_base);
+        kfree(rqst->rq_iov);
+}
+
 struct smb_version_operations smb20_operations = {
         .compare_fids = smb2_compare_fids,
         .setup_request = smb2_setup_request,
@@ -1793,6 +2045,8 @@ struct smb_version_operations smb30_operations = {
         .dir_needs_close = smb2_dir_needs_close,
         .fallocate = smb3_fallocate,
         .enum_snapshots = smb3_enum_snapshots,
+        .init_transform_rq = smb3_init_transform_rq,
+        .free_transform_rq = smb3_free_transform_rq,
 };
 
 #ifdef CONFIG_CIFS_SMB311
@@ -1881,6 +2135,8 @@ struct smb_version_operations smb311_operations = {
         .dir_needs_close = smb2_dir_needs_close,
         .fallocate = smb3_fallocate,
         .enum_snapshots = smb3_enum_snapshots,
+        .init_transform_rq = smb3_init_transform_rq,
+        .free_transform_rq = smb3_free_transform_rq,
 };
 #endif /* CIFS_SMB311 */
 
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 35ff9fae1c27..c03b252501a1 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -134,11 +134,14 @@ struct smb2_pdu {
         __le16 StructureSize2; /* size of wct area (varies, request specific) */
 } __packed;
 
+#define SMB3_AES128CMM_NONCE 11
+#define SMB3_AES128GCM_NONCE 12
+
 struct smb2_transform_hdr {
         __be32 smb2_buf_length; /* big endian on wire */
                                 /* length is only two or three bytes - with
                                  one or two byte type preceding it that MBZ */
-        __u8   ProtocolId[4];   /* 0xFD 'S' 'M' 'B' */
+        __le32 ProtocolId;      /* 0xFD 'S' 'M' 'B' */
         __u8   Signature[16];
         __u8   Nonce[16];
         __le32 OriginalMessageSize;
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index f2d511a6971b..7d30b754e132 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -56,6 +56,8 @@ extern void smb2_echo_request(struct work_struct *work);
 extern __le32 smb2_get_lease_state(struct cifsInodeInfo *cinode);
 extern bool smb2_is_valid_oplock_break(char *buffer,
                                        struct TCP_Server_Info *srv);
+extern struct cifs_ses *smb2_find_smb_ses(struct TCP_Server_Info *server,
+                                          __u64 ses_id);
 
 extern void move_smb2_info_to_cifs(FILE_ALL_INFO *dst,
                                    struct smb2_file_all_info *src);
@@ -97,6 +99,7 @@ extern int smb2_unlock_range(struct cifsFileInfo *cfile,
                              struct file_lock *flock, const unsigned int xid);
 extern int smb2_push_mandatory_locks(struct cifsFileInfo *cfile);
 extern void smb2_reconnect_server(struct work_struct *work);
+extern int smb3_crypto_aead_allocate(struct TCP_Server_Info *server);
 
 /*
  * SMB2 Worker functions - most of protocol specific implementation details
diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index 93b27752b634..3caa11dd957a 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -31,6 +31,7 @@
 #include <asm/processor.h>
 #include <linux/mempool.h>
 #include <linux/highmem.h>
+#include <crypto/aead.h>
 #include "smb2pdu.h"
 #include "cifsglob.h"
 #include "cifsproto.h"
@@ -114,14 +115,14 @@ smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
         return 0;
 }
 
-static struct cifs_ses *
-smb2_find_smb_ses(struct smb2_sync_hdr *shdr, struct TCP_Server_Info *server)
+struct cifs_ses *
+smb2_find_smb_ses(struct TCP_Server_Info *server, __u64 ses_id)
 {
         struct cifs_ses *ses;
 
         spin_lock(&cifs_tcp_ses_lock);
         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
-                if (ses->Suid != shdr->SessionId)
+                if (ses->Suid != ses_id)
                         continue;
                 spin_unlock(&cifs_tcp_ses_lock);
                 return ses;
@@ -141,7 +142,7 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
         struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
         struct cifs_ses *ses;
 
-        ses = smb2_find_smb_ses(shdr, server);
+        ses = smb2_find_smb_ses(server, shdr->SessionId);
         if (!ses) {
                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
                 return 0;
@@ -358,7 +359,7 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
         struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
         struct cifs_ses *ses;
 
-        ses = smb2_find_smb_ses(shdr, server);
+        ses = smb2_find_smb_ses(server, shdr->SessionId);
         if (!ses) {
                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
                 return 0;
@@ -618,3 +619,33 @@ smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 
         return mid;
 }
+
+int
+smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
+{
+        struct crypto_aead *tfm;
+
+        if (!server->secmech.ccmaesencrypt) {
+                tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
+                if (IS_ERR(tfm)) {
+                        cifs_dbg(VFS, "%s: Failed to alloc encrypt aead\n",
+                                 __func__);
+                        return PTR_ERR(tfm);
+                }
+                server->secmech.ccmaesencrypt = tfm;
+        }
+
+        if (!server->secmech.ccmaesdecrypt) {
+                tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
+                if (IS_ERR(tfm)) {
+                        crypto_free_aead(server->secmech.ccmaesencrypt);
+                        server->secmech.ccmaesencrypt = NULL;
+                        cifs_dbg(VFS, "%s: Failed to alloc decrypt aead\n",
+                                 __func__);
+                        return PTR_ERR(tfm);
+                }
+                server->secmech.ccmaesdecrypt = tfm;
+        }
+
+        return 0;
+}