Implement support for AES-GMAC message signing, as specified in
MS-SMB2 3.1.4.1 "Signing An Outgoing Message".
The core function is smb311_calc_aes_gmac(), which will be used as the
->calc_signature op when SIGNING_ALG_AES_GMAC has been negotiated with
the server.
If "enable_negotiate_signing" is false (default) or if
SIGNING_ALG_AES_GMAC was not negotiated, use AES-CMAC.
Changes:
- convert cifs_secmech sign/verify to unions, where .aead is for
AES-GMAC TFM and .shash for all the others signing algorithms
- init_sg(): rename to smb3_init_sg(), make it non-static, remove skip
variable. This makes it fit for both crypt_message() and
smb311_calc_signature()
- crypt_message(): advance the 20 bytes of rqst[0].rq_iov[0] that are
not part of the encrypted blob before calling smb3_init_sg(). Rewind
it back right after the call. (this was done in init_sg() via the
skip variable)
- needed to move the ->calc_signature op to inside secmech since
changing it within the smb_version_operations struct would make it
incompatible with multiple connections with different algorithms or
dialects
Other smaller modifications:
- smb2_setup_request(): check if the request has a transform header as we
must not sign an encrypted message (MS-SMB2 3.2.4.1.1)
- smb2_verify_signature():
* check if MessageId is 0xFFFFFFFFFFFFFFFF or if status is
STATUS_PENDING (MS-SMB2 3.2.5.1.3)
* remove extra call to zero the header signature as this is already
done by all ->calc_signature implementations
* remove useless call to check for "BSRSPYL" signature (SMB1 only),
and from smb2_sign_rqst() as well
Signed-off-by: Enzo Matsumiya <ematsumiya@xxxxxxx>
---
v4:
- rename smb311_calc_signature to smb311_calc_aes_gmac, and use SMB3_AES_GCM_NONCE
instead of hardcoded '12' (suggested by metze)
- update commit message to include the reasoning to move ->calc_signature op
fs/cifs/cifsencrypt.c | 23 ++-
fs/cifs/cifsglob.h | 40 +++--
fs/cifs/smb2ops.c | 38 ++---
fs/cifs/smb2pdu.c | 81 +++++-----
fs/cifs/smb2proto.h | 9 +-
fs/cifs/smb2transport.c | 331 ++++++++++++++++++++++++++++++----------
6 files changed, 355 insertions(+), 167 deletions(-)
diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index 4ae58ab29458..3a78efc45a23 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -23,6 +23,7 @@
#include <linux/fips.h>
#include "../smbfs_common/arc4.h"
#include <crypto/aead.h>
+#include "smb2proto.h"
int __cifs_calc_signature(struct smb_rqst *rqst,
struct TCP_Server_Info *server, char *signature,
@@ -105,9 +106,9 @@ static int cifs_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *se
return -EINVAL;
if (verify)
- shash = server->secmech.verify;
+ shash = server->secmech.verify.shash;
else
- shash = server->secmech.sign;
+ shash = server->secmech.sign.shash;
rc = crypto_shash_init(shash);
if (rc) {
@@ -703,16 +704,14 @@ calc_seckey(struct cifs_ses *ses)
void
cifs_crypto_secmech_release(struct TCP_Server_Info *server)
{
- cifs_free_hash(&server->secmech.sign);
- cifs_free_hash(&server->secmech.verify);
-
- if (server->secmech.enc) {
- crypto_free_aead(server->secmech.enc);
- server->secmech.enc = NULL;
+ if (server->signing_algorithm == SIGNING_ALG_AES_GMAC) {
+ smb3_crypto_aead_free(&server->secmech.sign.aead);
+ smb3_crypto_aead_free(&server->secmech.verify.aead);
+ } else {
+ cifs_free_hash(&server->secmech.sign.shash);
+ cifs_free_hash(&server->secmech.verify.shash);
}
- if (server->secmech.dec) {
- crypto_free_aead(server->secmech.dec);
- server->secmech.dec = NULL;
- }
+ smb3_crypto_aead_free(&server->secmech.enc);
+ smb3_crypto_aead_free(&server->secmech.dec);
}
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 30b3fadb4b06..81a8eff06467 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -153,24 +153,48 @@ struct session_key {
char *response;
};
+struct smb_rqst;
+struct TCP_Server_Info;
/**
* cifs_secmech - Crypto hashing related structure/fields, not specific to one mechanism
- * @sign: SHASH descriptor to allocate a hashing TFM for signing requests
- * @verify: SHASH descriptor to allocate a hashing TFM for verifying requests' signatures
+ * @sign.shash: SHASH descriptor for signing TFM
+ * @sign.aead: AEAD TFM for signing
+ * @sign_wait: Completion struct for signing operations
+ * @verify.shash: SHASH descriptor for verifying TFM
+ * @verify.aead: AEAD TFM for verifying
+ * @verify_wait: Completion struct for verifying operations
+ * @calc_signature: Signature calculation function to be used.
* @enc: AEAD TFM for SMB3+ encryption
* @dec: AEAD TFM for SMB3+ decryption
*
- * @sign and @verify are allocated per-server, and the negotiated connection dialect will dictate
- * which algorithm to use:
+ * @sign and @verify TFMs are allocated per-server, and the negotiated dialect will dictate which
+ * algorithm to use:
* - MD5 for SMB1
* - HMAC-SHA256 for SMB2
* - AES-CMAC for SMB3
+ * - AES-GMAC for SMB3.1.1
+ *
+ * The completion structs @sign_wait and @verify_wait are required so that we can serialize access
+ * to the AEAD TFMs, since they're asynchronous by design. Using a stack-allocated structure could
+ * cause concurrent access to the TFMs to overwrite the completion status of a previous operation.
*
- * @enc and @dec holds the encryption/decryption TFMs, where it'll be either AES-CCM or AES-GCM.
+ * @enc and @dec holds the encryption/decryption TFMs, also allocated per server, where each will
+ * be either AES-CCM or AES-GCM.
*/
struct cifs_secmech {
- struct shash_desc *sign;
- struct shash_desc *verify;
+ union {
+ struct shash_desc *shash;
+ struct crypto_aead *aead;
+ } sign;
+ struct crypto_wait sign_wait;
+
+ union {
+ struct shash_desc *shash;
+ struct crypto_aead *aead;
+ } verify;
+ struct crypto_wait verify_wait;
+
+ int (*calc_signature)(struct smb_rqst *rqst, struct TCP_Server_Info *server, bool verify);
struct crypto_aead *enc;
struct crypto_aead *dec;
@@ -445,8 +469,6 @@ struct smb_version_operations {
void (*new_lease_key)(struct cifs_fid *);
int (*generate_signingkey)(struct cifs_ses *ses,
struct TCP_Server_Info *server);
- int (*calc_signature)(struct smb_rqst *, struct TCP_Server_Info *,
- bool allocate_crypto);
int (*set_integrity)(const unsigned int, struct cifs_tcon *tcon,
struct cifsFileInfo *src_file);
int (*enum_snapshots)(const unsigned int xid, struct cifs_tcon *tcon,
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 0aaad18e1ec8..e08065103b61 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4234,21 +4234,14 @@ static inline void smb2_sg_set_buf(struct scatterlist *sg, const void *buf,
sg_set_page(sg, addr, buflen, offset_in_page(buf));
}
-/* Assumes the first rqst has a transform header as the first iov.
- * I.e.
- * rqst[0].rq_iov[0] is transform header
- * rqst[0].rq_iov[1+] data to be encrypted/decrypted
- * rqst[1+].rq_iov[0+] data to be encrypted/decrypted
- */
-static struct scatterlist *
-init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign)
+struct scatterlist *
+smb3_init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign)
{
unsigned int sg_len;
struct scatterlist *sg;
unsigned int i;
unsigned int j;
unsigned int idx = 0;
- int skip;
sg_len = 1;
for (i = 0; i < num_rqst; i++)
@@ -4261,15 +4254,10 @@ init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign)
sg_init_table(sg, sg_len);
for (i = 0; i < num_rqst; i++) {
for (j = 0; j < rqst[i].rq_nvec; j++) {
- /*
- * The first rqst has a transform header where the
- * first 20 bytes are not part of the encrypted blob
- */
- skip = (i == 0) && (j == 0) ? 20 : 0;
smb2_sg_set_buf(&sg[idx++],
- rqst[i].rq_iov[j].iov_base + skip,
- rqst[i].rq_iov[j].iov_len - skip);
- }
+ rqst[i].rq_iov[j].iov_base,
+ rqst[i].rq_iov[j].iov_len);
+ }
for (j = 0; j < rqst[i].rq_npages; j++) {
unsigned int len, offset;
@@ -4325,7 +4313,17 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst,
crypt_len += SMB2_SIGNATURE_SIZE;
}
- sg = init_sg(num_rqst, rqst, sign);
+ /*
+ * Skip the first 20 bytes of the first iov of the first request as they're not part of the
+ * encrypted blob
+ */
+ rqst[0].rq_iov[0].iov_base += 20;
+ rqst[0].rq_iov[0].iov_len -= 20;
+ sg = smb3_init_sg(num_rqst, rqst, sign);
+ /* Rewind those 20 bytes before going any further */
+ rqst[0].rq_iov[0].iov_base -= 20;
+ rqst[0].rq_iov[0].iov_len += 20;
+
if (!sg) {
cifs_server_dbg(VFS, "%s: Failed to init sg\n", __func__);
rc = -ENOMEM;
@@ -5213,7 +5211,6 @@ struct smb_version_operations smb20_operations = {
.get_lease_key = smb2_get_lease_key,
.set_lease_key = smb2_set_lease_key,
.new_lease_key = smb2_new_lease_key,
- .calc_signature = smb2_calc_signature,
.is_read_op = smb2_is_read_op,
.set_oplock_level = smb2_set_oplock_level,
.create_lease_buf = smb2_create_lease_buf,
@@ -5314,7 +5311,6 @@ struct smb_version_operations smb21_operations = {
.get_lease_key = smb2_get_lease_key,
.set_lease_key = smb2_set_lease_key,
.new_lease_key = smb2_new_lease_key,
- .calc_signature = smb2_calc_signature,
.is_read_op = smb21_is_read_op,
.set_oplock_level = smb21_set_oplock_level,
.create_lease_buf = smb2_create_lease_buf,
@@ -5421,7 +5417,6 @@ struct smb_version_operations smb30_operations = {
.set_lease_key = smb2_set_lease_key,
.new_lease_key = smb2_new_lease_key,
.generate_signingkey = generate_smb30signingkey,
- .calc_signature = smb2_calc_signature,
.set_integrity = smb3_set_integrity,
.is_read_op = smb21_is_read_op,
.set_oplock_level = smb3_set_oplock_level,
@@ -5535,7 +5530,6 @@ struct smb_version_operations smb311_operations = {
.set_lease_key = smb2_set_lease_key,
.new_lease_key = smb2_new_lease_key,
.generate_signingkey = generate_smb311signingkey,
- .calc_signature = smb2_calc_signature,
.set_integrity = smb3_set_integrity,
.is_read_op = smb21_is_read_op,
.set_oplock_level = smb3_set_oplock_level,
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index e5939c374c35..d7d6cbe6ba3b 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -460,7 +460,7 @@ static unsigned int
build_signing_ctxt(struct smb2_signing_capabilities *pneg_ctxt)
{
unsigned int ctxt_len = sizeof(struct smb2_signing_capabilities);
- unsigned short num_algs = 1; /* number of signing algorithms sent */
+ unsigned short num_algs = 2; /* number of signing algorithms sent */
pneg_ctxt->ContextType = SMB2_SIGNING_CAPABILITIES;
/*
@@ -471,12 +471,18 @@ build_signing_ctxt(struct smb2_signing_capabilities *pneg_ctxt)
sizeof(struct smb2_neg_context) +
(num_algs * 2 /* sizeof u16 */), 8) * 8);
pneg_ctxt->SigningAlgorithmCount = cpu_to_le16(num_algs);
- pneg_ctxt->SigningAlgorithms[0] = cpu_to_le16(SIGNING_ALG_AES_CMAC);
+
+ /*
+ * Set AES-GMAC as preferred, but will fall back to AES-CMAC if server doesn't support it.
+ * MS-SMB2 2.2.3.1.7
+ */
+ pneg_ctxt->SigningAlgorithms[0] = SIGNING_ALG_AES_GMAC_LE;
+ pneg_ctxt->SigningAlgorithms[1] = SIGNING_ALG_AES_CMAC_LE;
+ /* SMB 3.1.1 doesn't accept HMAC-SHA256, so no need to send it */
ctxt_len += 2 /* sizeof le16 */ * num_algs;
ctxt_len = DIV_ROUND_UP(ctxt_len, 8) * 8;
return ctxt_len;
- /* TBD add SIGNING_ALG_AES_GMAC and/or SIGNING_ALG_HMAC_SHA256 */
}
static void
@@ -927,22 +933,6 @@ SMB2_negotiate(const unsigned int xid,
else
req->SecurityMode = 0;
- if (req->SecurityMode) {
- /*
- * Allocate HMAC-SHA256 regardless of dialect requested, change to AES-CMAC later,
- * if SMB3+ is negotiated
- */
- rc = cifs_alloc_hash("hmac(sha256)", &server->secmech.sign);
- if (rc)
- goto neg_exit;
-
- rc = cifs_alloc_hash("hmac(sha256)", &server->secmech.verify);
- if (rc) {
- cifs_free_hash(&server->secmech.sign);
- goto neg_exit;
- }
- }
-
req->Capabilities = cpu_to_le32(server->vals->req_capabilities);
if (ses->chan_max > 1)
req->Capabilities |= cpu_to_le32(SMB2_GLOBAL_CAP_MULTI_CHANNEL);
@@ -1087,22 +1077,6 @@ SMB2_negotiate(const unsigned int xid,
rc = cifs_enable_signing(server, ses->sign);
if (rc)
goto neg_exit;
-
- if (server->sign && server->dialect >= SMB30_PROT_ID) {
- /* free HMAC-SHA256 allocated earlier for negprot */
- cifs_free_hash(&server->secmech.sign);
- cifs_free_hash(&server->secmech.verify);
- rc = cifs_alloc_hash("cmac(aes)", &server->secmech.sign);
- if (rc)
- goto neg_exit;
-
- rc = cifs_alloc_hash("cmac(aes)", &server->secmech.verify);
- if (rc) {
- cifs_free_hash(&server->secmech.sign);
- goto neg_exit;
- }
- }
-
if (blob_length) {
rc = decode_negTokenInit(security_blob, blob_length, server);
if (rc == 1)
@@ -1112,12 +1086,34 @@ SMB2_negotiate(const unsigned int xid,
}
if (rsp->DialectRevision == cpu_to_le16(SMB311_PROT_ID)) {
+ server->signing_algorithm = SIGNING_ALG_AES_CMAC;
+ server->signing_negotiated = false;
+
if (rsp->NegotiateContextCount)
rc = smb311_decode_neg_context(rsp, server,
rsp_iov.iov_len);
else
cifs_server_dbg(VFS, "Missing expected negotiate contexts\n");
+
+ /*
+ * Some servers will not send a SMB2_SIGNING_CAPABILITIES context response (*),
+ * so use AES-CMAC signing algorithm as it is expected to be accepted.
+ * See MS-SMB2 note <125> Section 3.2.4.2.2.2
+ */
+ if (!server->signing_negotiated)
+ cifs_dbg(VFS, "signing capabilities were not negotiated, using AES-CMAC for message signing\n");
+ } else if (server->dialect >= SMB30_PROT_ID) {
+ server->signing_algorithm = SIGNING_ALG_AES_CMAC;
+ } else if (server->dialect >= SMB20_PROT_ID) {
+ server->signing_algorithm = SIGNING_ALG_HMAC_SHA256;
}
+
+ rc = smb2_init_secmechs(server);
+ if (rc) {
+ cifs_dbg(VFS, "Failed to initialize secmechs, rc=%d\n", rc);
+ goto neg_exit;
+ }
+
neg_exit:
free_rsp_buf(resp_buftype, rsp);
return rc;
@@ -1677,18 +1673,13 @@ SMB2_sess_auth_rawntlmssp_authenticate(struct SMB2_sess_data *sess_data)
goto out;
if (ses->server->dialect < SMB30_PROT_ID) {
- rc = crypto_shash_setkey(server->secmech.sign->tfm,
- ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
- if (rc) {
- cifs_dbg(VFS, "%s: Failed to set HMAC-SHA256 signing key, rc=%d\n",
- __func__, rc);
- goto out;
- }
-
- rc = crypto_shash_setkey(server->secmech.verify->tfm,
+ rc = crypto_shash_setkey(server->secmech.sign.shash->tfm,
ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
+ if (!rc)
+ rc = crypto_shash_setkey(server->secmech.verify.shash->tfm,
+ ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
if (rc) {
- cifs_dbg(VFS, "%s: Failed to set HMAC-SHA256 verify key, rc=%d\n",
+ cifs_dbg(VFS, "%s: Failed to set HMAC-SHA256 signing keys, rc=%d\n",
__func__, rc);
goto out;
}
diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 33af35b6e586..cc38e1784a97 100644
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -14,6 +14,7 @@
struct statfs;
struct smb_rqst;
+struct crypto_aead;
/*
*****************************************************************
@@ -37,6 +38,7 @@ extern struct mid_q_entry *smb2_setup_request(struct cifs_ses *ses,
struct smb_rqst *rqst);
extern struct mid_q_entry *smb2_setup_async_request(
struct TCP_Server_Info *server, struct smb_rqst *rqst);
+extern int smb2_init_secmechs(struct TCP_Server_Info *server);
extern struct cifs_ses *smb2_find_smb_ses(struct TCP_Server_Info *server,
__u64 ses_id);
extern struct cifs_tcon *smb2_find_smb_tcon(struct TCP_Server_Info *server,
@@ -44,6 +46,10 @@ extern struct cifs_tcon *smb2_find_smb_tcon(struct TCP_Server_Info *server,
extern int smb2_calc_signature(struct smb_rqst *rqst,
struct TCP_Server_Info *server,
bool verify);
+extern int smb311_calc_aes_gmac(struct smb_rqst *rqst,
+ struct TCP_Server_Info *server,
+ bool verify);
+extern struct scatterlist *smb3_init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign);
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,
@@ -99,7 +105,8 @@ 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);
+extern int smb3_crypto_aead_allocate(const char *name, struct crypto_aead **tfm);
+extern void smb3_crypto_aead_free(struct crypto_aead **tfm);
extern unsigned long smb_rqst_len(struct TCP_Server_Info *server,
struct smb_rqst *rqst);
extern void smb2_set_next_command(struct cifs_tcon *tcon,
diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index cf319fc25161..df2fcd798bbc 100644
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -26,6 +26,63 @@
#include "smb2status.h"
#include "smb2glob.h"
+int
+smb2_init_secmechs(struct TCP_Server_Info *server)
+{
+ int rc = 0;
+
+ if (server->dialect >= SMB30_PROT_ID &&
+ (server->capabilities & SMB2_GLOBAL_CAP_ENCRYPTION)) {
+ if (server->cipher_type == SMB2_ENCRYPTION_AES128_GCM ||
+ server->cipher_type == SMB2_ENCRYPTION_AES256_GCM) {
+ rc = smb3_crypto_aead_allocate("gcm(aes)", &server->secmech.enc);
+ if (!rc)
+ rc = smb3_crypto_aead_allocate("gcm(aes)", &server->secmech.dec);
+ } else {
+ rc = smb3_crypto_aead_allocate("ccm(aes)", &server->secmech.enc);
+ if (!rc)
+ rc = smb3_crypto_aead_allocate("ccm(aes)", &server->secmech.dec);
+ }
+
+ if (rc)
+ return rc;
+ }
+
+ if (server->signing_algorithm == SIGNING_ALG_AES_GMAC) {
+ cifs_free_hash(&server->secmech.sign.shash);
+ cifs_free_hash(&server->secmech.verify.shash);
+
+ rc = smb3_crypto_aead_allocate("gcm(aes)", &server->secmech.sign.aead);
+ if (!rc)
+ rc = smb3_crypto_aead_allocate("gcm(aes)", &server->secmech.verify.aead);
+ if (rc) {
+ smb3_crypto_aead_free(&server->secmech.sign.aead);
+ return rc;
+ }
+
+ server->secmech.calc_signature = smb311_calc_aes_gmac;
+ } else {
+ char *shash_alg;
+
+ if (server->dialect >= SMB30_PROT_ID)
+ shash_alg = "cmac(aes)";
+ else
+ shash_alg = "hmac(sha256)";
+
+ rc = cifs_alloc_hash(shash_alg, &server->secmech.sign.shash);
+ if (!rc)
+ rc = cifs_alloc_hash(shash_alg, &server->secmech.verify.shash);
+ if (rc) {
+ cifs_free_hash(&server->secmech.sign.shash);
+ return rc;
+ }
+
+ server->secmech.calc_signature = smb2_calc_signature;
+ }
+
+ return rc;
+}
+
static int
smb3_setup_keys(struct TCP_Server_Info *server, u8 *sign_key, u8 *enc_key, u8 *dec_key)
{
@@ -42,44 +99,51 @@ smb3_setup_keys(struct TCP_Server_Info *server, u8 *sign_key, u8 *enc_key, u8 *d
crypt_keylen = SMB3_GCM128_CRYPTKEY_SIZE;
rc = crypto_aead_setkey(server->secmech.enc, enc_key, crypt_keylen);
+ if (!rc)
+ rc = crypto_aead_setkey(server->secmech.dec, dec_key, crypt_keylen);
if (rc) {
- cifs_server_dbg(VFS, "%s: Failed to set AEAD encryption key, rc=%d\n",
+ cifs_server_dbg(VFS, "%s: Failed to set encryption/decryption key, rc=%d\n",
__func__, rc);
return rc;
}
rc = crypto_aead_setauthsize(server->secmech.enc, SMB2_SIGNATURE_SIZE);
+ if (!rc)
+ rc = crypto_aead_setauthsize(server->secmech.dec, SMB2_SIGNATURE_SIZE);
if (rc) {
- cifs_server_dbg(VFS, "%s: Failed to set AEAD encryption authsize, rc=%d\n",
- __func__, rc);
- return rc;
- }
-
- rc = crypto_aead_setkey(server->secmech.dec, dec_key, crypt_keylen);
- if (rc) {
- cifs_server_dbg(VFS, "%s: Failed to set AEAD decryption key, rc=%d\n",
- __func__, rc);
- return rc;
- }
-
- rc = crypto_aead_setauthsize(server->secmech.dec, SMB2_SIGNATURE_SIZE);
- if (rc) {
- cifs_server_dbg(VFS, "%s: Failed to set AEAD decryption authsize, rc=%d\n",
+ cifs_server_dbg(VFS, "%s: Failed to set encryption/decryption authsize, rc=%d\n",
__func__, rc);
return rc;
}
setup_sign:
- rc = crypto_shash_setkey(server->secmech.sign->tfm, sign_key, SMB3_SIGN_KEY_SIZE);
- if (rc) {
- cifs_server_dbg(VFS, "%s: Failed to set AES-CMAC signing key, rc=%d\n",
- __func__, rc);
- return rc;
- }
+ if (server->signing_algorithm == SIGNING_ALG_AES_GMAC) {
+ rc = crypto_aead_setkey(server->secmech.sign.aead, sign_key, SMB3_SIGN_KEY_SIZE);
+ if (!rc)
+ rc = crypto_aead_setkey(server->secmech.verify.aead, sign_key,
+ SMB3_SIGN_KEY_SIZE);
+ if (rc) {
+ cifs_server_dbg(VFS, "%s: Failed to set AES-GMAC key, rc=%d\n",
+ __func__, rc);
+ return rc;
+ }
- rc = crypto_shash_setkey(server->secmech.verify->tfm, sign_key, SMB3_SIGN_KEY_SIZE);
- if (rc)
- cifs_server_dbg(VFS, "%s: Failed to set AES-CMAC verify key, rc=%d\n",
- __func__, rc);
+ rc = crypto_aead_setauthsize(server->secmech.sign.aead, SMB2_SIGNATURE_SIZE);
+ if (!rc)
+ rc = crypto_aead_setauthsize(server->secmech.verify.aead,
+ SMB2_SIGNATURE_SIZE);
+ if (rc)
+ cifs_server_dbg(VFS, "%s: Failed to set AES-GMAC authsize, rc=%d\n",
+ __func__, rc);
+ } else {
+ rc = crypto_shash_setkey(server->secmech.sign.shash->tfm, sign_key,
+ SMB3_SIGN_KEY_SIZE);
+ if (!rc)
+ rc = crypto_shash_setkey(server->secmech.verify.shash->tfm, sign_key,
+ SMB3_SIGN_KEY_SIZE);
+ if (rc)
+ cifs_server_dbg(VFS, "%s: Failed to set %s signing key, rc=%d\n", __func__,
+ crypto_shash_alg_name(server->secmech.sign.shash->tfm), rc);
+ }
return rc;
}
@@ -171,9 +235,9 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server, bool
memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
if (verify)
- shash = server->secmech.verify;
+ shash = server->secmech.verify.shash;
else
- shash = server->secmech.sign;
+ shash = server->secmech.sign.shash;
rc = crypto_shash_init(shash);
if (rc) {
@@ -360,10 +424,6 @@ generate_smb3signingkey(struct cifs_ses *ses,
if (rc)
goto out_zero_keys;
- rc = smb3_crypto_aead_allocate(server);
- if (rc)
- goto out_zero_keys;
-
rc = smb3_setup_keys(ses->server, sign_key, enc_key, dec_key);
if (rc)
goto out_zero_keys;
@@ -471,6 +531,125 @@ generate_smb311signingkey(struct cifs_ses *ses,
return generate_smb3signingkey(ses, server, &triplet);
}
+/*
+ * This function implements AES-GMAC signing for SMB2 messages as described in MS-SMB2
+ * specification. This algorithm is only supported on SMB 3.1.1.
+ *
+ * Note: even though Microsoft mentions RFC4543 in MS-SMB2, the mechanism used _must_ be the "raw"
+ * AES-128-GCM ("gcm(aes)"); RFC4543 is designed for IPsec and trying to use "rfc4543(gcm(aes)))"
+ * will fail the signature computation.
+ *
+ * MS-SMB2 3.1.4.1
+ */
+int
+smb311_calc_aes_gmac(struct smb_rqst *rqst, struct TCP_Server_Info *server, bool verify)
+{
+ union {
+ struct {
+ /* for MessageId (8 bytes) */
+ __le64 mid;
+ /* for role (client or server) and if SMB2 CANCEL (4 bytes) */
+ __le32 role;
+ };
+ u8 buffer[SMB3_AES_GCM_NONCE];
+ } __packed nonce;
+ u8 sig[SMB2_SIGNATURE_SIZE] = { 0 };
+ struct aead_request *aead_req = NULL;
+ struct crypto_aead *tfm = NULL;
+ struct scatterlist *sg = NULL;
+ unsigned long assoclen;
+ struct smb2_hdr *shdr = NULL;
+ struct crypto_wait *wait;
+ unsigned int save_npages = 0;
+ int rc = 0;
+
+ if (verify) {
+ wait = &server->secmech.verify_wait;
+ tfm = server->secmech.verify.aead;
+ } else {
+ wait = &server->secmech.sign_wait;
+ tfm = server->secmech.sign.aead;
+ }
+
+ if (completion_done(&wait->completion))
+ reinit_completion(&wait->completion);
+
+ shdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+
+ memset(shdr->Signature, 0, SMB2_SIGNATURE_SIZE);
+ memset(&nonce, 0, SMB3_AES_GCM_NONCE);
+
+ /* note that nonce must always be little endian */
+ nonce.mid = shdr->MessageId;
+ /* request is coming from the server, set LSB */
+ nonce.role |= shdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR;
+ /* set penultimate LSB if SMB2_CANCEL command */
+ if (shdr->Command == SMB2_CANCEL)
+ nonce.role |= cpu_to_le32(1UL << 1);
+
+ aead_req = aead_request_alloc(tfm, GFP_KERNEL);
+ if (!aead_req) {
+ cifs_dbg(VFS, "%s: Failed to alloc AEAD request\n", __func__);
+ return -ENOMEM;
+ }
+
+ /* skip page data if non-success error status, as it will compute an invalid signature */
+ if (shdr->Status != 0 && rqst->rq_npages > 0) {
+ save_npages = rqst->rq_npages;
+ rqst->rq_npages = 0;
+ }
+
+ assoclen = smb_rqst_len(server, rqst);
+
+ sg = smb3_init_sg(1, rqst, sig);
+ if (!sg) {
+ cifs_dbg(VFS, "%s: Failed to init SG\n", __func__);
+ goto out_free_req;
+ }
+
+ /* cryptlen == 0 because we're not encrypting anything */
+ aead_request_set_crypt(aead_req, sg, sg, 0, nonce.buffer);
+ aead_request_set_ad(aead_req, assoclen);
+ aead_request_set_callback(aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG, crypto_req_done, wait);
+
+ /*
+ * Reminder: we must always use the encrypt function, as AES-GCM decrypt will internally
+ * try to match the authentication codes, where we pass a zeroed buffer, and the operation
+ * will fail with -EBADMSG (expectedly).
+ *
+ * Also note we can't use crypto_wait_req() here since it's not interruptible.
+ */
+ rc = crypto_aead_encrypt(aead_req);
+ if (!rc)
+ goto out;
+
+ if (rc == -EINPROGRESS || rc == -EBUSY) {
+ rc = wait_for_completion_interruptible(&wait->completion);
+ if (!rc)
+ /* wait->err is set by crypto_req_done callback above */
+ rc = wait->err;
+ }
+
+ if (rc) {
+ cifs_server_dbg(VFS, "%s: Failed to compute AES-GMAC signature, rc=%d\n",
+ __func__, rc);
+ goto out_free_sg;
+ }
+
+out:
+ memcpy(&shdr->Signature, sig, SMB2_SIGNATURE_SIZE);
+out_free_sg:
+ kfree(sg);
+out_free_req:
+ kfree(aead_req);
+
+ /* restore rq_npages for further processing */
+ if (shdr->Status != 0 && save_npages > 0)
+ rqst->rq_npages = save_npages;
+
+ return rc;
+}
+
/* must be called with server->srv_mutex held */
static int
smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
@@ -497,12 +676,10 @@ smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
return 0;
}
spin_unlock(&server->srv_lock);
- if (!is_binding && !server->session_estab) {
- strncpy(shdr->Signature, "BSRSPYL", 8);
+ if (!is_binding && !server->session_estab)
return 0;
- }
- rc = server->ops->calc_signature(rqst, server, false);
+ rc = server->secmech.calc_signature(rqst, server, false);
return rc;
}
@@ -518,6 +695,8 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
if ((shdr->Command == SMB2_NEGOTIATE) ||
(shdr->Command == SMB2_SESSION_SETUP) ||
(shdr->Command == SMB2_OPLOCK_BREAK) ||
+ (shdr->MessageId == cpu_to_le64(0xFFFFFFFFFFFFFFFF)) ||
+ (shdr->Status == STATUS_PENDING) ||
server->ignore_signature ||
(!server->session_estab))
return 0;
@@ -527,20 +706,13 @@ smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
* server does not send one? BB
*/
- /* Do not need to verify session setups with signature "BSRSPYL " */
- if (memcmp(shdr->Signature, "BSRSPYL ", 8) == 0)
- cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
- shdr->Command);
-
/*
* Save off the origiginal signature so we can modify the smb and check
* our calculated signature against what the server sent.
*/
memcpy(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE);
- memset(shdr->Signature, 0, SMB2_SIGNATURE_SIZE);
-
- rc = server->ops->calc_signature(rqst, server, true);
+ rc = server->secmech.calc_signature(rqst, server, true);
if (rc)
return rc;
@@ -693,6 +865,8 @@ smb2_setup_request(struct cifs_ses *ses, struct TCP_Server_Info *server,
int rc;
struct smb2_hdr *shdr =
(struct smb2_hdr *)rqst->rq_iov[0].iov_base;
+ struct smb2_transform_hdr *trhdr =
+ (struct smb2_transform_hdr *)rqst->rq_iov[0].iov_base;
struct mid_q_entry *mid;
smb2_seq_num_into_buf(server, shdr);
@@ -703,11 +877,22 @@ smb2_setup_request(struct cifs_ses *ses, struct TCP_Server_Info *server,
return ERR_PTR(rc);
}
- rc = smb2_sign_rqst(rqst, server);
- if (rc) {
- revert_current_mid_from_hdr(server, shdr);
- delete_mid(mid);
- return ERR_PTR(rc);
+ /*
+ * Client must not sign the request if it's encrypted.
+ *
+ * Note: we can't rely on SMB2_SESSION_FLAG_ENCRYPT_DATA or SMB2_GLOBAL_CAP_ENCRYPTION
+ * here because they might be set, but not being actively used (e.g. not mounted with
+ * "seal"), so just check if header is a transform header.
+ *
+ * MS-SMB2 3.2.4.1.1
+ */
+ if (trhdr->ProtocolId != SMB2_TRANSFORM_PROTO_NUM) {
+ rc = smb2_sign_rqst(rqst, server);
+ if (rc) {
+ revert_current_mid_from_hdr(server, shdr);
+ delete_mid(mid);
+ return ERR_PTR(rc);
+ }
}
return mid;
@@ -748,39 +933,29 @@ smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
}
int
-smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
+smb3_crypto_aead_allocate(const char *name, struct crypto_aead **tfm)
{
- struct crypto_aead *tfm;
+ if (unlikely(!tfm))
+ return -EIO;
- if (!server->secmech.enc) {
- if ((server->cipher_type == SMB2_ENCRYPTION_AES128_GCM) ||
- (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM))
- tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
- else
- tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
- if (IS_ERR(tfm)) {
- cifs_server_dbg(VFS, "%s: Failed alloc encrypt aead\n",
- __func__);
- return PTR_ERR(tfm);
- }
- server->secmech.enc = tfm;
- }
+ if (*tfm)
+ return 0;
- if (!server->secmech.dec) {
- if ((server->cipher_type == SMB2_ENCRYPTION_AES128_GCM) ||
- (server->cipher_type == SMB2_ENCRYPTION_AES256_GCM))
- tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
- else
- tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
- if (IS_ERR(tfm)) {
- crypto_free_aead(server->secmech.enc);
- server->secmech.enc = NULL;
- cifs_server_dbg(VFS, "%s: Failed to alloc decrypt aead\n",
- __func__);
- return PTR_ERR(tfm);
- }
- server->secmech.dec = tfm;
+ *tfm = crypto_alloc_aead(name, CRYPTO_ALG_TYPE_AEAD, 0);
+ if (IS_ERR(*tfm)) {
+ cifs_dbg(VFS, "%s: Failed to alloc %s crypto TFM, rc=%ld\n",
+ __func__, name, PTR_ERR(*tfm));
+ return PTR_ERR(*tfm);
}
return 0;
}
+
+void smb3_crypto_aead_free(struct crypto_aead **tfm)
+{
+ if (!tfm || !*tfm)
+ return;
+
+ crypto_free_aead(*tfm);
+ *tfm = NULL;
+}
--
2.35.3
