Eliminate sparse warning - bad constant expression

Eliminiate sparse warning during usage of crypto_shash_* APIs
       error: bad constant expression

Allocate memory for shash descriptors once, so that we do not kmalloc/kfree it
for every signature generation (shash descriptor for md5 hash).

From ed7538619817777decc44b5660b52268077b74f3 Mon Sep 17 00:00:00 2001
From: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Date: Tue, 24 Aug 2010 11:47:43 -0500
Subject: [PATCH] eliminate sparse warnings during crypto_shash_* APis usage

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

2 files changed, 128 insertions, 72 deletions

diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
index eef78c24e0cc..709f2296bdb4 100644
--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -45,39 +45,38 @@ extern void SMBencrypt(unsigned char *passwd, const unsigned char *c8,
 static int cifs_calculate_signature(const struct smb_hdr *cifs_pdu,
                         struct TCP_Server_Info *server, char *signature)
 {
-        int rc = 0;
-        struct {
-                struct shash_desc shash;
-                char ctx[crypto_shash_descsize(server->ntlmssp.md5)];
-        } sdesc;
+        int rc;
 
         if (cifs_pdu == NULL || server == NULL || signature == NULL)
                 return -EINVAL;
 
-        sdesc.shash.tfm = server->ntlmssp.md5;
-        sdesc.shash.flags = 0x0;
+        if (!server->ntlmssp.sdescmd5) {
+                cERROR(1,
+                        "cifs_calculate_signature: can't generate signature\n");
+                return -1;
+        }
 
-        rc = crypto_shash_init(&sdesc.shash);
+        rc = crypto_shash_init(&server->ntlmssp.sdescmd5->shash);
         if (rc) {
-                cERROR(1, "could not initialize master crypto API hmacmd5\n");
+                cERROR(1, "cifs_calculate_signature: oould not init md5\n");
                 return rc;
         }
 
         if (server->secType == RawNTLMSSP)
-                crypto_shash_update(&sdesc.shash,
+                crypto_shash_update(&server->ntlmssp.sdescmd5->shash,
                         server->session_key.data.ntlmv2.key,
                         CIFS_NTLMV2_SESSKEY_SIZE);
         else
-                crypto_shash_update(&sdesc.shash,
+                crypto_shash_update(&server->ntlmssp.sdescmd5->shash,
                         (char *)&server->session_key.data,
                         server->session_key.len);
 
-        crypto_shash_update(&sdesc.shash,
+        crypto_shash_update(&server->ntlmssp.sdescmd5->shash,
                         cifs_pdu->Protocol, cifs_pdu->smb_buf_length);
 
-        rc = crypto_shash_final(&sdesc.shash, signature);
+        rc = crypto_shash_final(&server->ntlmssp.sdescmd5->shash, signature);
 
-        return 0;
+        return rc;
 }
 
 
@@ -115,30 +114,28 @@ static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
                         struct TCP_Server_Info *server, char *signature)
 {
         int i;
-        int rc = 0;
-        struct {
-                struct shash_desc shash;
-                char ctx[crypto_shash_descsize(server->ntlmssp.md5)];
-        } sdesc;
+        int rc;
 
         if (iov == NULL || server == NULL || signature == NULL)
                 return -EINVAL;
 
-        sdesc.shash.tfm = server->ntlmssp.md5;
-        sdesc.shash.flags = 0x0;
+        if (!server->ntlmssp.sdescmd5) {
+                cERROR(1, "cifs_calc_signature2: can't generate signature\n");
+                return -1;
+        }
 
-        rc = crypto_shash_init(&sdesc.shash);
+        rc = crypto_shash_init(&server->ntlmssp.sdescmd5->shash);
         if (rc) {
-                cERROR(1, "could not initialize master crypto API hmacmd5\n");
+                cERROR(1, "cifs_calc_signature2: oould not init md5\n");
                 return rc;
         }
 
         if (server->secType == RawNTLMSSP)
-                crypto_shash_update(&sdesc.shash,
+                crypto_shash_update(&server->ntlmssp.sdescmd5->shash,
                         server->session_key.data.ntlmv2.key,
                         CIFS_NTLMV2_SESSKEY_SIZE);
         else
-                crypto_shash_update(&sdesc.shash,
+                crypto_shash_update(&server->ntlmssp.sdescmd5->shash,
                         (char *)&server->session_key.data,
                         server->session_key.len);
 
@@ -146,7 +143,7 @@ static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
                 if (iov[i].iov_len == 0)
                         continue;
                 if (iov[i].iov_base == NULL) {
-                        cERROR(1, "null iovec entry");
+                        cERROR(1, "cifs_calc_signature2: null iovec entry");
                         return -EIO;
                 }
                 /* The first entry includes a length field (which does not get
@@ -154,16 +151,16 @@ static int cifs_calc_signature2(const struct kvec *iov, int n_vec,
                 if (i == 0) {
                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
                                 break; /* nothing to sign or corrupt header */
-                        crypto_shash_update(&sdesc.shash,
+                        crypto_shash_update(&server->ntlmssp.sdescmd5->shash,
                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
                 } else
-                        crypto_shash_update(&sdesc.shash,
+                        crypto_shash_update(&server->ntlmssp.sdescmd5->shash,
                                 iov[i].iov_base, iov[i].iov_len);
         }
 
-        rc = crypto_shash_final(&sdesc.shash, signature);
+        rc = crypto_shash_final(&server->ntlmssp.sdescmd5->shash, signature);
 
-        return 0;
+        return rc;
 }
 
 int cifs_sign_smb2(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
@@ -313,43 +310,48 @@ static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
         wchar_t *user;
         wchar_t *domain;
         wchar_t *server;
-        struct {
-                struct shash_desc shash;
-                char ctx[crypto_shash_descsize(ses->server->ntlmssp.hmacmd5)];
-        } sdesc;
+
+        if (!ses->server->ntlmssp.sdeschmacmd5) {
+                cERROR(1, "calc_ntlmv2_hash: can't generate ntlmv2 hash\n");
+                return -1;
+        }
 
         /* calculate md4 hash of password */
         E_md4hash(ses->password, nt_hash);
 
-        sdesc.shash.tfm = ses->server->ntlmssp.hmacmd5;
-        sdesc.shash.flags = 0x0;
-
         crypto_shash_setkey(ses->server->ntlmssp.hmacmd5, nt_hash,
                                 CIFS_NTHASH_SIZE);
 
-        rc = crypto_shash_init(&sdesc.shash);
+        rc = crypto_shash_init(&ses->server->ntlmssp.sdeschmacmd5->shash);
         if (rc) {
-                cERROR(1, "could not initialize master crypto API hmacmd5\n");
+                cERROR(1, "calc_ntlmv2_hash: could not init hmacmd5\n");
                 return rc;
         }
 
         /* convert ses->userName to unicode and uppercase */
         len = strlen(ses->userName);
         user = kmalloc(2 + (len * 2), GFP_KERNEL);
-        if (user == NULL)
+        if (user == NULL) {
+                cERROR(1, "calc_ntlmv2_hash: user mem alloc failure\n");
+                rc = -ENOMEM;
                 goto calc_exit_2;
+        }
         len = cifs_strtoUCS((__le16 *)user, ses->userName, len, nls_cp);
         UniStrupr(user);
 
-        crypto_shash_update(&sdesc.shash, (char *)user, 2 * len);
+        crypto_shash_update(&ses->server->ntlmssp.sdeschmacmd5->shash,
+                                (char *)user, 2 * len);
 
         /* convert ses->domainName to unicode and uppercase */
         if (ses->domainName) {
                 len = strlen(ses->domainName);
 
                 domain = kmalloc(2 + (len * 2), GFP_KERNEL);
-                if (domain == NULL)
+                if (domain == NULL) {
+                        cERROR(1, "calc_ntlmv2_hash: domain mem alloc failure");
+                        rc = -ENOMEM;
                         goto calc_exit_1;
+                }
                 len = cifs_strtoUCS((__le16 *)domain, ses->domainName, len,
                                         nls_cp);
                 /* the following line was removed since it didn't work well
@@ -357,15 +359,19 @@ static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
                    Maybe converting the domain name earlier makes sense */
                 /* UniStrupr(domain); */
 
-                crypto_shash_update(&sdesc.shash, (char *)domain, 2 * len);
+                crypto_shash_update(&ses->server->ntlmssp.sdeschmacmd5->shash,
+                                        (char *)domain, 2 * len);
 
                 kfree(domain);
         } else if (ses->serverName) {
                 len = strlen(ses->serverName);
 
                 server = kmalloc(2 + (len * 2), GFP_KERNEL);
-                if (server == NULL)
+                if (server == NULL) {
+                        cERROR(1, "calc_ntlmv2_hash: server mem alloc failure");
+                        rc = -ENOMEM;
                         goto calc_exit_1;
+                }
                 len = cifs_strtoUCS((__le16 *)server, ses->serverName, len,
                                         nls_cp);
                 /* the following line was removed since it didn't work well
@@ -373,16 +379,20 @@ static int calc_ntlmv2_hash(struct cifsSesInfo *ses,
                    Maybe converting the domain name earlier makes sense */
                 /* UniStrupr(domain); */
 
-                crypto_shash_update(&sdesc.shash, (char *)server, 2 * len);
+                crypto_shash_update(&ses->server->ntlmssp.sdeschmacmd5->shash,
+                                        (char *)server, 2 * len);
 
                 kfree(server);
         }
+
+        rc = crypto_shash_final(&ses->server->ntlmssp.sdeschmacmd5->shash,
+                                        ses->server->ntlmv2_hash);
+
 calc_exit_1:
         kfree(user);
 calc_exit_2:
         /* BB FIXME what about bytes 24 through 40 of the signing key?
            compare with the NTLM example */
-        rc = crypto_shash_final(&sdesc.shash, ses->server->ntlmv2_hash);
 
         return rc;
 }
@@ -442,34 +452,33 @@ CalcNTLMv2_response(const struct TCP_Server_Info *server,
                          char *v2_session_response)
 {
         int rc;
-        struct {
-                struct shash_desc shash;
-                char ctx[crypto_shash_descsize(server->ntlmssp.hmacmd5)];
-        } sdesc;
 
-        sdesc.shash.tfm = server->ntlmssp.hmacmd5;
-        sdesc.shash.flags = 0x0;
+        if (!server->ntlmssp.sdeschmacmd5) {
+                cERROR(1, "calc_ntlmv2_hash: can't generate ntlmv2 hash\n");
+                return -1;
+        }
 
         crypto_shash_setkey(server->ntlmssp.hmacmd5, server->ntlmv2_hash,
                 CIFS_HMAC_MD5_HASH_SIZE);
 
-        rc = crypto_shash_init(&sdesc.shash);
+        rc = crypto_shash_init(&server->ntlmssp.sdeschmacmd5->shash);
         if (rc) {
-                cERROR(1, "could not initialize master crypto API hmacmd5\n");
+                cERROR(1, "CalcNTLMv2_response: could not init hmacmd5");
                 return rc;
         }
 
         memcpy(v2_session_response + CIFS_SERVER_CHALLENGE_SIZE,
                 server->cryptKey, CIFS_SERVER_CHALLENGE_SIZE);
-        crypto_shash_update(&sdesc.shash,
+        crypto_shash_update(&server->ntlmssp.sdeschmacmd5->shash,
                 v2_session_response + CIFS_SERVER_CHALLENGE_SIZE,
                 sizeof(struct ntlmv2_resp) - CIFS_SERVER_CHALLENGE_SIZE);
 
         if (server->tilen)
-                crypto_shash_update(&sdesc.shash,
+                crypto_shash_update(&server->ntlmssp.sdeschmacmd5->shash,
                                         server->tiblob, server->tilen);
 
-        rc = crypto_shash_final(&sdesc.shash, v2_session_response);
+        rc = crypto_shash_final(&server->ntlmssp.sdeschmacmd5->shash,
+                                        v2_session_response);
 
         return rc;
 }
@@ -480,10 +489,6 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
 {
         int rc = 0;
         struct ntlmv2_resp *buf = (struct ntlmv2_resp *)resp_buf;
-        struct {
-                struct shash_desc shash;
-                char ctx[crypto_shash_descsize(ses->server->ntlmssp.hmacmd5)];
-        } sdesc;
 
         buf->blob_signature = cpu_to_le32(0x00000101);
         buf->reserved = 0;
@@ -511,21 +516,24 @@ setup_ntlmv2_rsp(struct cifsSesInfo *ses, char *resp_buf,
                 return rc;
         }
 
+        if (!ses->server->ntlmssp.sdeschmacmd5) {
+                cERROR(1, "calc_ntlmv2_hash: can't generate ntlmv2 hash\n");
+                return -1;
+        }
+
         crypto_shash_setkey(ses->server->ntlmssp.hmacmd5,
                         ses->server->ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
 
-        sdesc.shash.tfm = ses->server->ntlmssp.hmacmd5;
-        sdesc.shash.flags = 0x0;
-
-        rc = crypto_shash_init(&sdesc.shash);
+        rc = crypto_shash_init(&ses->server->ntlmssp.sdeschmacmd5->shash);
         if (rc) {
-                cERROR(1, "could not initialize master crypto API hmacmd5\n");
+                cERROR(1, "setup_ntlmv2_rsp: could not init hmacmd5\n");
                 return rc;
         }
 
-        crypto_shash_update(&sdesc.shash, resp_buf, CIFS_HMAC_MD5_HASH_SIZE);
+        crypto_shash_update(&ses->server->ntlmssp.sdeschmacmd5->shash,
+                                resp_buf, CIFS_HMAC_MD5_HASH_SIZE);
 
-        rc = crypto_shash_final(&sdesc.shash,
+        rc = crypto_shash_final(&ses->server->ntlmssp.sdeschmacmd5->shash,
                 ses->server->session_key.data.ntlmv2.key);
 
         memcpy(&ses->server->session_key.data.ntlmv2.resp, resp_buf,
@@ -578,24 +586,65 @@ cifs_crypto_shash_release(struct TCP_Server_Info *server)
 
         if (server->ntlmssp.hmacmd5)
                 crypto_free_shash(server->ntlmssp.hmacmd5);
+
+        kfree(server->ntlmssp.sdeschmacmd5);
+
+        kfree(server->ntlmssp.sdescmd5);
 }
 
 int
 cifs_crypto_shash_allocate(struct TCP_Server_Info *server)
 {
+        int rc;
+        unsigned int size;
+
         server->ntlmssp.hmacmd5 = crypto_alloc_shash("hmac(md5)", 0, 0);
         if (!server->ntlmssp.hmacmd5 ||
                         IS_ERR(server->ntlmssp.hmacmd5)) {
-                cERROR(1, "could not allocate master crypto API hmacmd5\n");
+                cERROR(1, "could not allocate crypto hmacmd5\n");
                 return 1;
         }
 
         server->ntlmssp.md5 = crypto_alloc_shash("md5", 0, 0);
         if (!server->ntlmssp.md5 || IS_ERR(server->ntlmssp.md5)) {
-                crypto_free_shash(server->ntlmssp.hmacmd5);
-                cERROR(1, "could not allocate master crypto API md5\n");
-                return 1;
+                cERROR(1, "could not allocate crypto md5\n");
+                rc = 1;
+                goto cifs_crypto_shash_allocate_ret1;
         }
 
+        size = sizeof(struct shash_desc) +
+                        crypto_shash_descsize(server->ntlmssp.hmacmd5);
+        server->ntlmssp.sdeschmacmd5 = kmalloc(size, GFP_KERNEL);
+        if (!server->ntlmssp.sdeschmacmd5) {
+                cERROR(1, "cifs_crypto_shash_allocate: can't alloc hmacmd5\n");
+                rc = -ENOMEM;
+                goto cifs_crypto_shash_allocate_ret2;
+        }
+        server->ntlmssp.sdeschmacmd5->shash.tfm = server->ntlmssp.hmacmd5;
+        server->ntlmssp.sdeschmacmd5->shash.flags = 0x0;
+
+
+        size = sizeof(struct shash_desc) +
+                        crypto_shash_descsize(server->ntlmssp.md5);
+        server->ntlmssp.sdescmd5 = kmalloc(size, GFP_KERNEL);
+        if (!server->ntlmssp.sdescmd5) {
+                cERROR(1, "cifs_crypto_shash_allocate: can't alloc md5\n");
+                rc = -ENOMEM;
+                goto cifs_crypto_shash_allocate_ret3;
+        }
+        server->ntlmssp.sdescmd5->shash.tfm = server->ntlmssp.md5;
+        server->ntlmssp.sdescmd5->shash.flags = 0x0;
+
         return 0;
+
+cifs_crypto_shash_allocate_ret3:
+        kfree(server->ntlmssp.sdeschmacmd5);
+
+cifs_crypto_shash_allocate_ret2:
+        crypto_free_shash(server->ntlmssp.md5);
+
+cifs_crypto_shash_allocate_ret1:
+        crypto_free_shash(server->ntlmssp.hmacmd5);
+
+        return rc;
 }
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 49563e0c1725..c9d0cfc086eb 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -123,12 +123,19 @@ struct cifs_cred {
         struct cifs_ace *aces;
 };
 
+struct sdesc {
+        struct shash_desc shash;
+        char ctx[];
+};
+
 struct ntlmssp_auth {
         __u32 client_flags;
         __u32 server_flags;
         unsigned char ciphertext[CIFS_CPHTXT_SIZE];
         struct crypto_shash *hmacmd5;
         struct crypto_shash *md5;
+        struct sdesc *sdeschmacmd5;
+        struct sdesc *sdescmd5;
 };
 
 /*