ksmbd: More crypto library conversions

PATCH Applied Eric Biggers 3 participants 8 messages Oct 14, 2025 – Oct 16, 2025

Subsystems (3)

Crypto API SMB client (CIFS) Kernel SMB3 server (ksmbd)

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Eric Biggers

author

2025-10-14 23:18 UTC #0 lore raw

cover ksmbd: More crypto library conversions

This series converts fs/smb/server/ to access SHA-512, HMAC-SHA256, and HMAC-MD5 using the library APIs instead of crypto_shash.

This simplifies the code significantly. It also slightly improves performance, as it eliminates unnecessary overhead. I haven't done server-specific benchmarks, but you can get an idea of what to expect by looking at the numbers I gave for the similar client-side series:
https://lore.kernel.org/linux-cifs/20251014034230.GC2763@sol/

No change in behavior intended. All the crypto computations should be the same as before. I haven't tested this series (I did test the similar client-side series), but everything should still work.

Eric Biggers (3):
ksmbd: Use SHA-512 library for SMB3.1.1 preauth hash
ksmbd: Use HMAC-SHA256 library for message signing and key generation
ksmbd: Use HMAC-MD5 library for NTLMv2

 fs/smb/server/Kconfig      |   6 +-
 fs/smb/server/auth.c       | 390 +++++++------------------------------
 fs/smb/server/auth.h       |  10 +-
 fs/smb/server/crypto_ctx.c |  24 ---
 fs/smb/server/crypto_ctx.h |  15 +-
 fs/smb/server/server.c     |   4 -
 fs/smb/server/smb2pdu.c    |  26 +--
 fs/smb/server/smb_common.h |   2 +-
 8 files changed, 87 insertions(+), 390 deletions(-)

base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787

Signature · 1 line

2.51.0

Eric Biggers

author

2025-10-14 23:18 UTC #1 lore raw

PATCH 1/3 ksmbd: Use SHA-512 library for SMB3.1.1 preauth hash

Convert ksmbd_gen_preauth_integrity_hash() to use the SHA-512 library instead of a "sha512" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the SHA-512 code is accessed directly without inefficient indirect calls and other unnecessary API overhead.

Signed-off-by Eric Biggers <[email protected]>

---
 fs/smb/server/Kconfig      |  2 +-
 fs/smb/server/auth.c       | 41 +++++++-------------------------------
 fs/smb/server/crypto_ctx.c |  8 --------
 fs/smb/server/crypto_ctx.h |  4 ----
 fs/smb/server/server.c     |  1 -
 5 files changed, 8 insertions(+), 48 deletions(-)

fs/smb/server/Kconfig +1 -1

index 098cac98d31e6..d5f3a417246d4 100644
@@ -11,13 +11,13 @@ config SMB_SERVER
 	select CRYPTO_HMAC
 	select CRYPTO_ECB
 	select CRYPTO_LIB_ARC4
 	select CRYPTO_LIB_DES
 	select CRYPTO_LIB_SHA256
+	select CRYPTO_LIB_SHA512
 	select CRYPTO_SHA256
 	select CRYPTO_CMAC
-	select CRYPTO_SHA512
 	select CRYPTO_AEAD2
 	select CRYPTO_CCM
 	select CRYPTO_GCM
 	select ASN1
 	select OID_REGISTRY

fs/smb/server/auth.c +7 ~~-34~~

69 lines not on this page · raw message

fs/smb/server/crypto_ctx.c +0 -8

index 80bd68c8635ea..1de41b10528bc 100644
@@ -73,13 +73,10 @@ static struct shash_desc *alloc_shash_desc(int id)
 		tfm = crypto_alloc_shash("hmac(sha256)", 0, 0);
 		break;
 	case CRYPTO_SHASH_CMACAES:
 		tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
 		break;
-	case CRYPTO_SHASH_SHA512:
-		tfm = crypto_alloc_shash("sha512", 0, 0);
-		break;
 	default:
 		return NULL;
 	}
 
 	if (IS_ERR(tfm))

@@ -193,15 +190,10 @@ struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacsha256(void)
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void)
 {
 	return ____crypto_shash_ctx_find(CRYPTO_SHASH_CMACAES);
 }
 
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_sha512(void)
-{
-	return ____crypto_shash_ctx_find(CRYPTO_SHASH_SHA512);
-}
-
 static struct ksmbd_crypto_ctx *____crypto_aead_ctx_find(int id)
 {
 	struct ksmbd_crypto_ctx *ctx;
 
 	if (id >= CRYPTO_AEAD_MAX)

fs/smb/server/crypto_ctx.h +0 -4

index ac64801d52d38..4e8954acd8b8b 100644
@@ -11,11 +11,10 @@
 
 enum {
 	CRYPTO_SHASH_HMACMD5	= 0,
 	CRYPTO_SHASH_HMACSHA256,
 	CRYPTO_SHASH_CMACAES,
-	CRYPTO_SHASH_SHA512,
 	CRYPTO_SHASH_MAX,
 };
 
 enum {
 	CRYPTO_AEAD_AES_GCM = 16,

@@ -36,26 +35,23 @@ struct ksmbd_crypto_ctx {
 };
 
 #define CRYPTO_HMACMD5(c)	((c)->desc[CRYPTO_SHASH_HMACMD5])
 #define CRYPTO_HMACSHA256(c)	((c)->desc[CRYPTO_SHASH_HMACSHA256])
 #define CRYPTO_CMACAES(c)	((c)->desc[CRYPTO_SHASH_CMACAES])
-#define CRYPTO_SHA512(c)	((c)->desc[CRYPTO_SHASH_SHA512])
 
 #define CRYPTO_HMACMD5_TFM(c)	((c)->desc[CRYPTO_SHASH_HMACMD5]->tfm)
 #define CRYPTO_HMACSHA256_TFM(c)\
 				((c)->desc[CRYPTO_SHASH_HMACSHA256]->tfm)
 #define CRYPTO_CMACAES_TFM(c)	((c)->desc[CRYPTO_SHASH_CMACAES]->tfm)
-#define CRYPTO_SHA512_TFM(c)	((c)->desc[CRYPTO_SHASH_SHA512]->tfm)
 
 #define CRYPTO_GCM(c)		((c)->ccmaes[CRYPTO_AEAD_AES_GCM])
 #define CRYPTO_CCM(c)		((c)->ccmaes[CRYPTO_AEAD_AES_CCM])
 
 void ksmbd_release_crypto_ctx(struct ksmbd_crypto_ctx *ctx);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacmd5(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacsha256(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void);
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_sha512(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_gcm(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_ccm(void);
 void ksmbd_crypto_destroy(void);
 int ksmbd_crypto_create(void);

fs/smb/server/server.c +0 -1

index 40420544cc25a..51e2aee2a6985 100644
@@ -626,11 +626,10 @@ MODULE_SOFTDEP("pre: hmac");
 MODULE_SOFTDEP("pre: md5");
 MODULE_SOFTDEP("pre: nls");
 MODULE_SOFTDEP("pre: aes");
 MODULE_SOFTDEP("pre: cmac");
 MODULE_SOFTDEP("pre: sha256");
-MODULE_SOFTDEP("pre: sha512");
 MODULE_SOFTDEP("pre: aead2");
 MODULE_SOFTDEP("pre: ccm");
 MODULE_SOFTDEP("pre: gcm");
 module_init(ksmbd_server_init)
 module_exit(ksmbd_server_exit)

Signature · 1 line

2.51.0

Eric Biggers

author

2025-10-14 23:18 UTC #2 lore raw

PATCH 2/3 ksmbd: Use HMAC-SHA256 library for message signing and key generation

In reply to Eric Biggers

Convert ksmbd_sign_smb2_pdu() and generate_key() to use the HMAC-SHA256 library instead of a "hmac(sha256)" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the HMAC-SHA256 code is accessed directly without inefficient indirect calls and other unnecessary API overhead.

Signed-off-by Eric Biggers <[email protected]>

---
 fs/smb/server/Kconfig      |   1 -
 fs/smb/server/auth.c       | 176 ++++++++-----------------------------
 fs/smb/server/auth.h       |  10 +--
 fs/smb/server/crypto_ctx.c |   8 --
 fs/smb/server/crypto_ctx.h |   5 --
 fs/smb/server/server.c     |   1 -
 fs/smb/server/smb2pdu.c    |  26 ++----
 fs/smb/server/smb_common.h |   2 +-
 8 files changed, 52 insertions(+), 177 deletions(-)

fs/smb/server/Kconfig +0 -1

index d5f3a417246d4..788104cfb082f 100644
@@ -12,11 +12,10 @@ config SMB_SERVER
 	select CRYPTO_ECB
 	select CRYPTO_LIB_ARC4
 	select CRYPTO_LIB_DES
 	select CRYPTO_LIB_SHA256
 	select CRYPTO_LIB_SHA512
-	select CRYPTO_SHA256
 	select CRYPTO_CMAC
 	select CRYPTO_AEAD2
 	select CRYPTO_CCM
 	select CRYPTO_GCM
 	select ASN1

fs/smb/server/auth.c +39 ~~-137~~

273 lines not on this page · raw message

fs/smb/server/auth.h +5 -5

index 6879a1bd1b91f..6d351d61b0e57 100644
@@ -50,20 +50,20 @@ int ksmbd_decode_ntlmssp_neg_blob(struct negotiate_message *negblob,
 unsigned int
 ksmbd_build_ntlmssp_challenge_blob(struct challenge_message *chgblob,
 				   struct ksmbd_conn *conn);
 int ksmbd_krb5_authenticate(struct ksmbd_session *sess, char *in_blob,
 			    int in_len,	char *out_blob, int *out_len);
-int ksmbd_sign_smb2_pdu(struct ksmbd_conn *conn, char *key, struct kvec *iov,
-			int n_vec, char *sig);
+void ksmbd_sign_smb2_pdu(struct ksmbd_conn *conn, char *key, struct kvec *iov,
+			 int n_vec, char *sig);
 int ksmbd_sign_smb3_pdu(struct ksmbd_conn *conn, char *key, struct kvec *iov,
 			int n_vec, char *sig);
 int ksmbd_gen_smb30_signingkey(struct ksmbd_session *sess,
 			       struct ksmbd_conn *conn);
 int ksmbd_gen_smb311_signingkey(struct ksmbd_session *sess,
 				struct ksmbd_conn *conn);
-int ksmbd_gen_smb30_encryptionkey(struct ksmbd_conn *conn,
-				  struct ksmbd_session *sess);
-int ksmbd_gen_smb311_encryptionkey(struct ksmbd_conn *conn,
+void ksmbd_gen_smb30_encryptionkey(struct ksmbd_conn *conn,
 				   struct ksmbd_session *sess);
+void ksmbd_gen_smb311_encryptionkey(struct ksmbd_conn *conn,
+				    struct ksmbd_session *sess);
 int ksmbd_gen_preauth_integrity_hash(struct ksmbd_conn *conn, char *buf,
 				     __u8 *pi_hash);
 #endif

fs/smb/server/crypto_ctx.c +0 -8

index 1de41b10528bc..a5ec22ba8ae37 100644
@@ -67,13 +67,10 @@ static struct shash_desc *alloc_shash_desc(int id)
 
 	switch (id) {
 	case CRYPTO_SHASH_HMACMD5:
 		tfm = crypto_alloc_shash("hmac(md5)", 0, 0);
 		break;
-	case CRYPTO_SHASH_HMACSHA256:
-		tfm = crypto_alloc_shash("hmac(sha256)", 0, 0);
-		break;
 	case CRYPTO_SHASH_CMACAES:
 		tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
 		break;
 	default:
 		return NULL;

@@ -180,15 +177,10 @@ static struct ksmbd_crypto_ctx *____crypto_shash_ctx_find(int id)
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacmd5(void)
 {
 	return ____crypto_shash_ctx_find(CRYPTO_SHASH_HMACMD5);
 }
 
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacsha256(void)
-{
-	return ____crypto_shash_ctx_find(CRYPTO_SHASH_HMACSHA256);
-}
-
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void)
 {
 	return ____crypto_shash_ctx_find(CRYPTO_SHASH_CMACAES);
 }

fs/smb/server/crypto_ctx.h +0 -5

index 4e8954acd8b8b..c571d65a16f3e 100644
@@ -9,11 +9,10 @@
 #include <crypto/hash.h>
 #include <crypto/aead.h>
 
 enum {
 	CRYPTO_SHASH_HMACMD5	= 0,
-	CRYPTO_SHASH_HMACSHA256,
 	CRYPTO_SHASH_CMACAES,
 	CRYPTO_SHASH_MAX,
 };
 
 enum {

@@ -33,24 +32,20 @@ struct ksmbd_crypto_ctx {
 	struct shash_desc		*desc[CRYPTO_SHASH_MAX];
 	struct crypto_aead		*ccmaes[CRYPTO_AEAD_MAX];
 };
 
 #define CRYPTO_HMACMD5(c)	((c)->desc[CRYPTO_SHASH_HMACMD5])
-#define CRYPTO_HMACSHA256(c)	((c)->desc[CRYPTO_SHASH_HMACSHA256])
 #define CRYPTO_CMACAES(c)	((c)->desc[CRYPTO_SHASH_CMACAES])
 
 #define CRYPTO_HMACMD5_TFM(c)	((c)->desc[CRYPTO_SHASH_HMACMD5]->tfm)
-#define CRYPTO_HMACSHA256_TFM(c)\
-				((c)->desc[CRYPTO_SHASH_HMACSHA256]->tfm)
 #define CRYPTO_CMACAES_TFM(c)	((c)->desc[CRYPTO_SHASH_CMACAES]->tfm)
 
 #define CRYPTO_GCM(c)		((c)->ccmaes[CRYPTO_AEAD_AES_GCM])
 #define CRYPTO_CCM(c)		((c)->ccmaes[CRYPTO_AEAD_AES_CCM])
 
 void ksmbd_release_crypto_ctx(struct ksmbd_crypto_ctx *ctx);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacmd5(void);
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacsha256(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_gcm(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_ccm(void);
 void ksmbd_crypto_destroy(void);
 int ksmbd_crypto_create(void);

fs/smb/server/server.c +0 -1

index 51e2aee2a6985..8bce97633e01a 100644
@@ -625,11 +625,10 @@ MODULE_SOFTDEP("pre: ecb");
 MODULE_SOFTDEP("pre: hmac");
 MODULE_SOFTDEP("pre: md5");
 MODULE_SOFTDEP("pre: nls");
 MODULE_SOFTDEP("pre: aes");
 MODULE_SOFTDEP("pre: cmac");
-MODULE_SOFTDEP("pre: sha256");
 MODULE_SOFTDEP("pre: aead2");
 MODULE_SOFTDEP("pre: ccm");
 MODULE_SOFTDEP("pre: gcm");
 module_init(ksmbd_server_init)
 module_exit(ksmbd_server_exit)

fs/smb/server/smb2pdu.c +7 ~~-19~~

index ab1d45fcebdef..b315b07bc4043 100644
@@ -1536,16 +1536,11 @@ static int ntlm_authenticate(struct ksmbd_work *work,
 	    (req->SecurityMode & SMB2_NEGOTIATE_SIGNING_REQUIRED))
 		sess->sign = true;
 
 	if (smb3_encryption_negotiated(conn) &&
 			!(req->Flags & SMB2_SESSION_REQ_FLAG_BINDING)) {
-		rc = conn->ops->generate_encryptionkey(conn, sess);
-		if (rc) {
-			ksmbd_debug(SMB,
-					"SMB3 encryption key generation failed\n");
-			return -EINVAL;
-		}
+		conn->ops->generate_encryptionkey(conn, sess);
 		sess->enc = true;
 		if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION)
 			rsp->SessionFlags = SMB2_SESSION_FLAG_ENCRYPT_DATA_LE;
 		/*
 		 * signing is disable if encryption is enable

@@ -1638,16 +1633,11 @@ static int krb5_authenticate(struct ksmbd_work *work,
 	    (req->SecurityMode & SMB2_NEGOTIATE_SIGNING_REQUIRED))
 		sess->sign = true;
 
 	if (smb3_encryption_negotiated(conn) &&
 	    !(req->Flags & SMB2_SESSION_REQ_FLAG_BINDING)) {
-		retval = conn->ops->generate_encryptionkey(conn, sess);
-		if (retval) {
-			ksmbd_debug(SMB,
-				    "SMB3 encryption key generation failed\n");
-			return -EINVAL;
-		}
+		conn->ops->generate_encryptionkey(conn, sess);
 		sess->enc = true;
 		if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_ENCRYPTION)
 			rsp->SessionFlags = SMB2_SESSION_FLAG_ENCRYPT_DATA_LE;
 		sess->sign = false;
 	}

@@ -8850,13 +8840,12 @@ int smb2_check_sign_req(struct ksmbd_work *work)
 	memset(hdr->Signature, 0, SMB2_SIGNATURE_SIZE);
 
 	iov[0].iov_base = (char *)&hdr->ProtocolId;
 	iov[0].iov_len = len;
 
-	if (ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, 1,
-				signature))
-		return 0;
+	ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, 1,
+			    signature);
 
 	if (memcmp(signature, signature_req, SMB2_SIGNATURE_SIZE)) {
 		pr_err("bad smb2 signature\n");
 		return 0;
 	}

@@ -8876,22 +8865,21 @@ void smb2_set_sign_rsp(struct ksmbd_work *work)
 	struct kvec *iov;
 	int n_vec = 1;
 
 	hdr = ksmbd_resp_buf_curr(work);
 	hdr->Flags |= SMB2_FLAGS_SIGNED;
-	memset(hdr->Signature, 0, SMB2_SIGNATURE_SIZE);
 
 	if (hdr->Command == SMB2_READ) {
 		iov = &work->iov[work->iov_idx - 1];
 		n_vec++;
 	} else {
 		iov = &work->iov[work->iov_idx];
 	}
 
-	if (!ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, n_vec,
-				 signature))
-		memcpy(hdr->Signature, signature, SMB2_SIGNATURE_SIZE);
+	ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, n_vec,
+			    signature);
+	memcpy(hdr->Signature, signature, SMB2_SIGNATURE_SIZE);
 }
 
 /**
  * smb3_check_sign_req() - handler for req packet sign processing
  * @work:   smb work containing notify command buffer

fs/smb/server/smb_common.h +1 -1

index d742ba754348b..b6e0659a7e414 100644
@@ -407,11 +407,11 @@ struct smb_version_ops {
 	int (*get_ksmbd_tcon)(struct ksmbd_work *work);
 	bool (*is_sign_req)(struct ksmbd_work *work, unsigned int command);
 	int (*check_sign_req)(struct ksmbd_work *work);
 	void (*set_sign_rsp)(struct ksmbd_work *work);
 	int (*generate_signingkey)(struct ksmbd_session *sess, struct ksmbd_conn *conn);
-	int (*generate_encryptionkey)(struct ksmbd_conn *conn, struct ksmbd_session *sess);
+	void (*generate_encryptionkey)(struct ksmbd_conn *conn, struct ksmbd_session *sess);
 	bool (*is_transform_hdr)(void *buf);
 	int (*decrypt_req)(struct ksmbd_work *work);
 	int (*encrypt_resp)(struct ksmbd_work *work);
 };

Signature · 1 line

2.51.0

Namjae Jeon

maintainer

2025-10-16 05:00 UTC #3 lore raw

Re: [PATCH 2/3] ksmbd: Use HMAC-SHA256 library for message signing and key generation

[snip]

fs/smb/server/smb2pdu.c void smb2_set_sign_rsp(struct ksmbd_work *work) · line 8881

Quoted 7 lines

fs/smb/server/smb2pdu.c +0 -1

@@ -8876,22 +8865,21 @@ void smb2_set_sign_rsp(struct ksmbd_work *work)
        struct kvec *iov;
        int n_vec = 1;
 
        hdr = ksmbd_resp_buf_curr(work);
        hdr->Flags |= SMB2_FLAGS_SIGNED;
-       memset(hdr->Signature, 0, SMB2_SIGNATURE_SIZE);

By deleting this line, the following error occurs.

[162118.260693] CIFS: VFS: sign fail cmd 0x3 message id 0x3
[162118.260707] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.261473] CIFS: VFS: sign fail cmd 0xb message id 0x4
[162118.261482] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.262437] CIFS: VFS: sign fail cmd 0x3 message id 0x5
[162118.262449] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.262892] CIFS: VFS: sign fail cmd 0x5 message id 0x6
[162118.262900] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.263301] CIFS: VFS: sign fail cmd 0x10 message id 0x7
[162118.263314] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.263724] CIFS: VFS: sign fail cmd 0x10 message id 0x8
[162118.263736] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.264142] CIFS: VFS: sign fail cmd 0x6 message id 0x9
[162118.264154] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.264591] CIFS: VFS: sign fail cmd 0x5 message id 0xa
[162118.264603] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.264912] CIFS: VFS: sign fail cmd 0x6 message id 0xb
[162118.264925] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.265244] CIFS: VFS: sign fail cmd 0x5 message id 0xc
[162118.265257] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162119.831575] CIFS: VFS: \\10.177.110.57\homes2 SMB signature

verification returned error = -13

I have directly restored this line manually and then applied this patch to #ksmbd-for-next-next.
Thanks!

Quoted 39 lines

fs/smb/server/smb2pdu.c +3 -3

        if (hdr->Command == SMB2_READ) {
                iov = &work->iov[work->iov_idx - 1];
                n_vec++;
        } else {
                iov = &work->iov[work->iov_idx];
        }
 
-       if (!ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, n_vec,
-                                signature))
-               memcpy(hdr->Signature, signature, SMB2_SIGNATURE_SIZE);
+       ksmbd_sign_smb2_pdu(work->conn, work->sess->sess_key, iov, n_vec,
+                           signature);
+       memcpy(hdr->Signature, signature, SMB2_SIGNATURE_SIZE);
 }
 
 /**
  * smb3_check_sign_req() - handler for req packet sign processing
  * @work:   smb work containing notify command buffer

fs/smb/server/smb_common.h +1 -2

index d742ba754348b..b6e0659a7e414 100644
@@ -407,11 +407,11 @@ struct smb_version_ops {
        int (*get_ksmbd_tcon)(struct ksmbd_work *work);
        bool (*is_sign_req)(struct ksmbd_work *work, unsigned int command);
        int (*check_sign_req)(struct ksmbd_work *work);
        void (*set_sign_rsp)(struct ksmbd_work *work);
        int (*generate_signingkey)(struct ksmbd_session *sess, struct ksmbd_conn *conn);
-       int (*generate_encryptionkey)(struct ksmbd_conn *conn, struct ksmbd_session *sess);
+       void (*generate_encryptionkey)(struct ksmbd_conn *conn, struct ksmbd_session *sess);
        bool (*is_transform_hdr)(void *buf);
        int (*decrypt_req)(struct ksmbd_work *work);
        int (*encrypt_resp)(struct ksmbd_work *work);
 };
 
--

2.51.0

Eric Biggers

author

2025-10-16 17:56 UTC #4 lore raw

Re: [PATCH 2/3] ksmbd: Use HMAC-SHA256 library for message signing and key generation

Quoted 41 lines · Namjae Jeon

[snip]

fs/smb/server/smb2pdu.c void smb2_set_sign_rsp(struct ksmbd_work *work) · line 8881

Quoted 7 lines

fs/smb/server/smb2pdu.c +0 -1

@@ -8876,22 +8865,21 @@ void smb2_set_sign_rsp(struct ksmbd_work *work)
        struct kvec *iov;
        int n_vec = 1;
 
        hdr = ksmbd_resp_buf_curr(work);
        hdr->Flags |= SMB2_FLAGS_SIGNED;
-       memset(hdr->Signature, 0, SMB2_SIGNATURE_SIZE);

By deleting this line, the following error occurs.

[162118.260693] CIFS: VFS: sign fail cmd 0x3 message id 0x3
[162118.260707] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.261473] CIFS: VFS: sign fail cmd 0xb message id 0x4
[162118.261482] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.262437] CIFS: VFS: sign fail cmd 0x3 message id 0x5
[162118.262449] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.262892] CIFS: VFS: sign fail cmd 0x5 message id 0x6
[162118.262900] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.263301] CIFS: VFS: sign fail cmd 0x10 message id 0x7
[162118.263314] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.263724] CIFS: VFS: sign fail cmd 0x10 message id 0x8
[162118.263736] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.264142] CIFS: VFS: sign fail cmd 0x6 message id 0x9
[162118.264154] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.264591] CIFS: VFS: sign fail cmd 0x5 message id 0xa
[162118.264603] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.264912] CIFS: VFS: sign fail cmd 0x6 message id 0xb
[162118.264925] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162118.265244] CIFS: VFS: sign fail cmd 0x5 message id 0xc
[162118.265257] CIFS: VFS: \\10.177.110.57 SMB signature verification
returned error = -13
[162119.831575] CIFS: VFS: \\10.177.110.57\homes2 SMB signature

Quoted 5 lines

verification returned error = -13
I have directly restored this line manually and then applied this patch to #ksmbd-for-next-next.
Thanks!

Thanks for catching that! It looked like zeroizing 'hdr->Signature' was only needed for when ksmbd_sign_smb2_pdu() failed. But it must be part of the HMAC input data as well, i.e. 'hdr' must point to the same memory as one of the iovecs. So restoring the line is fine. Thanks,

- Eric

Eric Biggers

author

2025-10-14 23:18 UTC #5 lore raw

PATCH 3/3 ksmbd: Use HMAC-MD5 library for NTLMv2

In reply to Eric Biggers

For the HMAC-MD5 computations in NTLMv2, use the HMAC-MD5 library instead of a "hmac(md5)" crypto_shash. This is simpler and faster. With the library there's no need to allocate memory, no need to handle errors, and the HMAC-MD5 code is accessed directly without inefficient indirect calls and other unnecessary API overhead.

To preserve the existing behavior of NTLMv2 support being disabled when the kernel is booted with "fips=1", make ksmbd_auth_ntlmv2() check fips_enabled itself. Previously it relied on the error from crypto_alloc_shash("hmac(md5)") being bubbled up. I don't know for sure that this is actually needed, but this preserves the existing behavior.

Signed-off-by Eric Biggers <[email protected]>

---
 fs/smb/server/Kconfig      |   3 +-
 fs/smb/server/auth.c       | 173 ++++++-------------------------------
 fs/smb/server/crypto_ctx.c |   8 --
 fs/smb/server/crypto_ctx.h |   6 +-
 fs/smb/server/server.c     |   2 -
 5 files changed, 27 insertions(+), 165 deletions(-)

fs/smb/server/Kconfig +1 -2

index 788104cfb082f..2775162c535c6 100644
@@ -5,15 +5,14 @@ config SMB_SERVER
 	depends on FILE_LOCKING
 	select NLS
 	select NLS_UTF8
 	select NLS_UCS2_UTILS
 	select CRYPTO
-	select CRYPTO_MD5
-	select CRYPTO_HMAC
 	select CRYPTO_ECB
 	select CRYPTO_LIB_ARC4
 	select CRYPTO_LIB_DES
+	select CRYPTO_LIB_MD5
 	select CRYPTO_LIB_SHA256
 	select CRYPTO_LIB_SHA512
 	select CRYPTO_CMAC
 	select CRYPTO_AEAD2
 	select CRYPTO_CCM

fs/smb/server/auth.c +25 ~~-148~~

243 lines not on this page · raw message

fs/smb/server/crypto_ctx.c +0 -8

index a5ec22ba8ae37..fe29d186baf68 100644
@@ -64,13 +64,10 @@ static struct shash_desc *alloc_shash_desc(int id)
 {
 	struct crypto_shash *tfm = NULL;
 	struct shash_desc *shash;
 
 	switch (id) {
-	case CRYPTO_SHASH_HMACMD5:
-		tfm = crypto_alloc_shash("hmac(md5)", 0, 0);
-		break;
 	case CRYPTO_SHASH_CMACAES:
 		tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
 		break;
 	default:
 		return NULL;

@@ -172,15 +169,10 @@ static struct ksmbd_crypto_ctx *____crypto_shash_ctx_find(int id)
 		return ctx;
 	ksmbd_release_crypto_ctx(ctx);
 	return NULL;
 }
 
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacmd5(void)
-{
-	return ____crypto_shash_ctx_find(CRYPTO_SHASH_HMACMD5);
-}
-
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void)
 {
 	return ____crypto_shash_ctx_find(CRYPTO_SHASH_CMACAES);
 }

fs/smb/server/crypto_ctx.h +1 -5

index c571d65a16f3e..b9476ed520ae4 100644
@@ -8,12 +8,11 @@
 
 #include <crypto/hash.h>
 #include <crypto/aead.h>
 
 enum {
-	CRYPTO_SHASH_HMACMD5	= 0,
-	CRYPTO_SHASH_CMACAES,
+	CRYPTO_SHASH_CMACAES	= 0,
 	CRYPTO_SHASH_MAX,
 };
 
 enum {
 	CRYPTO_AEAD_AES_GCM = 16,

@@ -31,21 +30,18 @@ struct ksmbd_crypto_ctx {
 
 	struct shash_desc		*desc[CRYPTO_SHASH_MAX];
 	struct crypto_aead		*ccmaes[CRYPTO_AEAD_MAX];
 };
 
-#define CRYPTO_HMACMD5(c)	((c)->desc[CRYPTO_SHASH_HMACMD5])
 #define CRYPTO_CMACAES(c)	((c)->desc[CRYPTO_SHASH_CMACAES])
 
-#define CRYPTO_HMACMD5_TFM(c)	((c)->desc[CRYPTO_SHASH_HMACMD5]->tfm)
 #define CRYPTO_CMACAES_TFM(c)	((c)->desc[CRYPTO_SHASH_CMACAES]->tfm)
 
 #define CRYPTO_GCM(c)		((c)->ccmaes[CRYPTO_AEAD_AES_GCM])
 #define CRYPTO_CCM(c)		((c)->ccmaes[CRYPTO_AEAD_AES_CCM])
 
 void ksmbd_release_crypto_ctx(struct ksmbd_crypto_ctx *ctx);
-struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_hmacmd5(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_cmacaes(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_gcm(void);
 struct ksmbd_crypto_ctx *ksmbd_crypto_ctx_find_ccm(void);
 void ksmbd_crypto_destroy(void);
 int ksmbd_crypto_create(void);

fs/smb/server/server.c +0 -2

index 8bce97633e01a..3cea16050e4f7 100644
@@ -620,12 +620,10 @@ static void __exit ksmbd_server_exit(void)
 
 MODULE_AUTHOR("Namjae Jeon <[email protected]>");
 MODULE_DESCRIPTION("Linux kernel CIFS/SMB SERVER");
 MODULE_LICENSE("GPL");
 MODULE_SOFTDEP("pre: ecb");
-MODULE_SOFTDEP("pre: hmac");
-MODULE_SOFTDEP("pre: md5");
 MODULE_SOFTDEP("pre: nls");
 MODULE_SOFTDEP("pre: aes");
 MODULE_SOFTDEP("pre: cmac");
 MODULE_SOFTDEP("pre: aead2");
 MODULE_SOFTDEP("pre: ccm");

Signature · 1 line

2.51.0

Steve French

2025-10-14 23:25 UTC #6 lore raw

cover ksmbd: More crypto library conversions

In reply to Eric Biggers

Adding linux-cifs mailing lists for more visibility to these changes

---------- Forwarded message ---------
From: Eric Biggers <[email protected]>
Date: Tue, Oct 14, 2025 at 6:18 PM
Subject: [PATCH 0/3] ksmbd: More crypto library conversions
To: <[email protected]>, Namjae Jeon <[email protected]>, Steve French <[email protected]>
Cc: Sergey Senozhatsky <[email protected]>, Tom Talpey <[email protected]>, <[email protected]>, <[email protected]>, Eric Biggers <[email protected]>

This series converts fs/smb/server/ to access SHA-512, HMAC-SHA256, and HMAC-MD5 using the library APIs instead of crypto_shash.

No change in behavior intended. All the crypto computations should be the same as before. I haven't tested this series (I did test the similar client-side series), but everything should still work.

Eric Biggers (3):
ksmbd: Use SHA-512 library for SMB3.1.1 preauth hash
ksmbd: Use HMAC-SHA256 library for message signing and key generation
ksmbd: Use HMAC-MD5 library for NTLMv2

 fs/smb/server/Kconfig      |   6 +-
 fs/smb/server/auth.c       | 390 +++++++------------------------------
 fs/smb/server/auth.h       |  10 +-
 fs/smb/server/crypto_ctx.c |  24 ---
 fs/smb/server/crypto_ctx.h |  15 +-
 fs/smb/server/server.c     |   4 -
 fs/smb/server/smb2pdu.c    |  26 +--
 fs/smb/server/smb_common.h |   2 +-
 8 files changed, 87 insertions(+), 390 deletions(-)

base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 --
2.51.0

Signature · 3 lines

Thanks,

Steve

Namjae Jeon

maintainer Applied

2025-10-16 05:03 UTC #7 lore raw

In reply to Eric Biggers

Quoted 10 lines · Eric Biggers

This series converts fs/smb/server/ to access SHA-512, HMAC-SHA256, and HMAC-MD5 using the library APIs instead of crypto_shash.
This simplifies the code significantly. It also slightly improves performance, as it eliminates unnecessary overhead. I haven't done server-specific benchmarks, but you can get an idea of what to expect by looking at the numbers I gave for the similar client-side series:
https://lore.kernel.org/linux-cifs/20251014034230.GC2763@sol/

Quoted 8 lines

No change in behavior intended. All the crypto computations should be the same as before. I haven't tested this series (I did test the similar client-side series), but everything should still work.
Eric Biggers (3):
ksmbd: Use SHA-512 library for SMB3.1.1 preauth hash
ksmbd: Use HMAC-SHA256 library for message signing and key generation
ksmbd: Use HMAC-MD5 library for NTLMv2

Applied them to #ksmbd-for-next-next.
Thanks!

Quoted 16 lines

 fs/smb/server/Kconfig      |   6 +-
 fs/smb/server/auth.c       | 390 +++++++------------------------------
 fs/smb/server/auth.h       |  10 +-
 fs/smb/server/crypto_ctx.c |  24 ---
 fs/smb/server/crypto_ctx.h |  15 +-
 fs/smb/server/server.c     |   4 -
 fs/smb/server/smb2pdu.c    |  26 +--
 fs/smb/server/smb_common.h |   2 +-
 8 files changed, 87 insertions(+), 390 deletions(-)

base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 --
2.51.0