From: Eric Biggers Date: Sat, 18 Apr 2026 22:13:08 +0000 (-0700) Subject: smb: client: Use AES-CMAC library for SMB3 signature calculation X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=3a4580e71371dc5d323ac1fb4af80316838aca14;p=thirdparty%2Fkernel%2Fstable.git smb: client: Use AES-CMAC library for SMB3 signature calculation Convert smb3_calc_signature() to use the AES-CMAC library instead of a "cmac(aes)" crypto_shash. The result is simpler and faster code. With the library there's no need to allocate memory, no need to handle errors except for key preparation, and the AES-CMAC code is accessed directly without inefficient indirect calls and other unnecessary API overhead. For now a "cmac(aes)" crypto_shash is still being allocated in 'struct cifs_secmech'. Later commits will remove that, simplifying the code even further. Reviewed-by: Ard Biesheuvel Signed-off-by: Eric Biggers Signed-off-by: Steve French --- diff --git a/fs/smb/client/Kconfig b/fs/smb/client/Kconfig index 63831242fddf..029bbe595d5f 100644 --- a/fs/smb/client/Kconfig +++ b/fs/smb/client/Kconfig @@ -10,6 +10,7 @@ config CIFS select CRYPTO_CCM select CRYPTO_GCM select CRYPTO_AES + select CRYPTO_LIB_AES_CBC_MACS select CRYPTO_LIB_ARC4 select CRYPTO_LIB_MD5 select CRYPTO_LIB_SHA256 diff --git a/fs/smb/client/cifsencrypt.c b/fs/smb/client/cifsencrypt.c index 3d731f3af235..d092bca2df62 100644 --- a/fs/smb/client/cifsencrypt.c +++ b/fs/smb/client/cifsencrypt.c @@ -22,49 +22,33 @@ #include #include #include +#include #include #include #include -static int cifs_sig_update(struct cifs_calc_sig_ctx *ctx, - const u8 *data, size_t len) +static size_t cifs_sig_step(void *iter_base, size_t progress, size_t len, + void *priv, void *priv2) { - if (ctx->md5) { - md5_update(ctx->md5, data, len); - return 0; - } - if (ctx->hmac) { - hmac_sha256_update(ctx->hmac, data, len); - return 0; - } - return crypto_shash_update(ctx->shash, data, len); + struct cifs_calc_sig_ctx *ctx = priv; + + if (ctx->md5) + md5_update(ctx->md5, iter_base, len); + else if (ctx->hmac) + hmac_sha256_update(ctx->hmac, iter_base, len); + else + aes_cmac_update(ctx->cmac, iter_base, len); + return 0; /* Return value is length *not* processed, i.e. 0. */ } -static int cifs_sig_final(struct cifs_calc_sig_ctx *ctx, u8 *out) +static void cifs_sig_final(struct cifs_calc_sig_ctx *ctx, u8 *out) { - if (ctx->md5) { + if (ctx->md5) md5_final(ctx->md5, out); - return 0; - } - if (ctx->hmac) { + else if (ctx->hmac) hmac_sha256_final(ctx->hmac, out); - return 0; - } - return crypto_shash_final(ctx->shash, out); -} - -static size_t cifs_sig_step(void *iter_base, size_t progress, size_t len, - void *priv, void *priv2) -{ - struct cifs_calc_sig_ctx *ctx = priv; - int ret, *pret = priv2; - - ret = cifs_sig_update(ctx, iter_base, len); - if (ret < 0) { - *pret = ret; - return len; - } - return 0; + else + aes_cmac_final(ctx->cmac, out); } /* @@ -75,9 +59,8 @@ static int cifs_sig_iter(const struct iov_iter *iter, size_t maxsize, { struct iov_iter tmp_iter = *iter; size_t did; - int err; - did = iterate_and_advance_kernel(&tmp_iter, maxsize, ctx, &err, + did = iterate_and_advance_kernel(&tmp_iter, maxsize, ctx, NULL, cifs_sig_step); if (did != maxsize) return smb_EIO2(smb_eio_trace_sig_iter, did, maxsize); @@ -108,11 +91,8 @@ int __cifs_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server, if (rc < 0) return rc; - rc = cifs_sig_final(ctx, signature); - if (rc) - cifs_dbg(VFS, "%s: Could not generate hash\n", __func__); - - return rc; + cifs_sig_final(ctx, signature); + return 0; } /* Build a proper attribute value/target info pairs blob. diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h index ccfde157d3be..74265d055c26 100644 --- a/fs/smb/client/cifsglob.h +++ b/fs/smb/client/cifsglob.h @@ -2324,7 +2324,7 @@ static inline void mid_execute_callback(struct TCP_Server_Info *server, struct cifs_calc_sig_ctx { struct md5_ctx *md5; struct hmac_sha256_ctx *hmac; - struct shash_desc *shash; + struct aes_cmac_ctx *cmac; }; #define CIFS_RECONN_DELAY_SECS 30 diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c index 81be2b226e26..b233e0cd9152 100644 --- a/fs/smb/client/smb2transport.c +++ b/fs/smb/client/smb2transport.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include "cifsglob.h" @@ -474,7 +475,8 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server, unsigned char smb3_signature[SMB2_CMACAES_SIZE]; struct kvec *iov = rqst->rq_iov; struct smb2_hdr *shdr = (struct smb2_hdr *)iov[0].iov_base; - struct shash_desc *shash = NULL; + struct aes_cmac_key cmac_key; + struct aes_cmac_ctx cmac_ctx; struct smb_rqst drqst; u8 key[SMB3_SIGN_KEY_SIZE]; @@ -487,33 +489,16 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server, return rc; } - if (allocate_crypto) { - rc = cifs_alloc_hash("cmac(aes)", &shash); - if (rc) - return rc; - } else { - shash = server->secmech.aes_cmac; - } - memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE); memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE); - rc = crypto_shash_setkey(shash->tfm, key, SMB2_CMACAES_SIZE); + rc = aes_cmac_preparekey(&cmac_key, key, SMB2_CMACAES_SIZE); if (rc) { cifs_server_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__); - goto out; + return rc; } - /* - * we already allocate aes_cmac when we init smb3 signing key, - * so unlike smb2 case we do not have to check here if secmech are - * initialized - */ - rc = crypto_shash_init(shash); - if (rc) { - cifs_server_dbg(VFS, "%s: Could not init cmac aes\n", __func__); - goto out; - } + aes_cmac_init(&cmac_ctx, &cmac_key); /* * For SMB2+, __cifs_calc_signature() expects to sign only the actual @@ -524,26 +509,16 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server, */ drqst = *rqst; if (drqst.rq_nvec >= 2 && iov[0].iov_len == 4) { - rc = crypto_shash_update(shash, iov[0].iov_base, - iov[0].iov_len); - if (rc) { - cifs_server_dbg(VFS, "%s: Could not update with payload\n", - __func__); - goto out; - } + aes_cmac_update(&cmac_ctx, iov[0].iov_base, iov[0].iov_len); drqst.rq_iov++; drqst.rq_nvec--; } rc = __cifs_calc_signature( &drqst, server, smb3_signature, - &(struct cifs_calc_sig_ctx){ .shash = shash }); + &(struct cifs_calc_sig_ctx){ .cmac = &cmac_ctx }); if (!rc) memcpy(shdr->Signature, smb3_signature, SMB2_SIGNATURE_SIZE); - -out: - if (allocate_crypto) - cifs_free_hash(&shash); return rc; }