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SubjectRe: [PATCH 2/6] cifs: merge the hash calculation helpers
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On Sat, 2016-04-09 at 21:50 +0100, Al Viro wrote:
> three practically identical copies...
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  fs/cifs/cifsencrypt.c   |  97 ++++++++++++++++++++++++-------------------
>  fs/cifs/cifsproto.h     |   3 ++
>  fs/cifs/smb2transport.c | 107 +++++-------------------------------------------
>  3 files changed, 67 insertions(+), 140 deletions(-)
>
> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
> index 4897dac..6aeb8d4 100644
> --- a/fs/cifs/cifsencrypt.c
> +++ b/fs/cifs/cifsencrypt.c
> @@ -66,45 +66,15 @@ cifs_crypto_shash_md5_allocate(struct TCP_Server_Info *server)
>   return 0;
>  }
>  
> -/*
> - * Calculate and return the CIFS signature based on the mac key and SMB PDU.
> - * The 16 byte signature must be allocated by the caller. Note we only use the
> - * 1st eight bytes and that the smb header signature field on input contains
> - * the sequence number before this function is called. Also, this function
> - * should be called with the server->srv_mutex held.
> - */
> -static int cifs_calc_signature(struct smb_rqst *rqst,
> - struct TCP_Server_Info *server, char *signature)
> +int __cifs_calc_signature(struct smb_rqst *rqst,
> + struct TCP_Server_Info *server, char *signature,
> + struct shash_desc *shash)
>  {
>   int i;
>   int rc;
>   struct kvec *iov = rqst->rq_iov;
>   int n_vec = rqst->rq_nvec;
>  
> - if (iov == NULL || signature == NULL || server == NULL)
> - return -EINVAL;
> -
> - if (!server->secmech.sdescmd5) {
> - rc = cifs_crypto_shash_md5_allocate(server);
> - if (rc) {
> - cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
> - return -1;
> - }
> - }
> -
> - rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
> - if (rc) {
> - cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
> - return rc;
> - }
> -
> - rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
> - server->session_key.response, server->session_key.len);
> - if (rc) {
> - cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
> - return rc;
> - }
> -
>   for (i = 0; i < n_vec; i++) {
>   if (iov[i].iov_len == 0)
>   continue;
> @@ -117,12 +87,10 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
>   if (i == 0) {
>   if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
>   break; /* nothing to sign or corrupt header */
> - rc =
> - crypto_shash_update(&server->secmech.sdescmd5->shash,
> + rc = crypto_shash_update(shash,
>   iov[i].iov_base + 4, iov[i].iov_len - 4);
>   } else {
> - rc =
> - crypto_shash_update(&server->secmech.sdescmd5->shash,
> + rc = crypto_shash_update(shash,
>   iov[i].iov_base, iov[i].iov_len);
>   }
>   if (rc) {
> @@ -134,21 +102,64 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
>  
>   /* now hash over the rq_pages array */
>   for (i = 0; i < rqst->rq_npages; i++) {
> - struct kvec p_iov;
> + void *kaddr = kmap(rqst->rq_pages[i]);
> + size_t len = rqst->rq_pagesz;
> +
> + if (i == rqst->rq_npages - 1)
> + len = rqst->rq_tailsz;
> +
> + crypto_shash_update(shash, kaddr, len);
>  
> - cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> - crypto_shash_update(&server->secmech.sdescmd5->shash,
> - p_iov.iov_base, p_iov.iov_len);
>   kunmap(rqst->rq_pages[i]);
>   }
>  
> - rc = crypto_shash_final(&server->secmech.sdescmd5->shash, signature);
> + rc = crypto_shash_final(shash, signature);
>   if (rc)
> - cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
> + cifs_dbg(VFS, "%s: Could not generate hash\n", __func__);
>  
>   return rc;
>  }
>  
> +/*
> + * Calculate and return the CIFS signature based on the mac key and SMB PDU.
> + * The 16 byte signature must be allocated by the caller. Note we only use the
> + * 1st eight bytes and that the smb header signature field on input contains
> + * the sequence number before this function is called. Also, this function
> + * should be called with the server->srv_mutex held.
> + */
> +static int cifs_calc_signature(struct smb_rqst *rqst,
> + struct TCP_Server_Info *server, char *signature)
> +{
> + int rc;
> +
> + if (!rqst->rq_iov || !signature || !server)
> + return -EINVAL;
> +
> + if (!server->secmech.sdescmd5) {
> + rc = cifs_crypto_shash_md5_allocate(server);
> + if (rc) {
> + cifs_dbg(VFS, "%s: Can't alloc md5 crypto\n", __func__);
> + return -1;
> + }
> + }
> +
> + rc = crypto_shash_init(&server->secmech.sdescmd5->shash);
> + if (rc) {
> + cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
> + return rc;
> + }
> +
> + rc = crypto_shash_update(&server->secmech.sdescmd5->shash,
> + server->session_key.response, server->session_key.len);
> + if (rc) {
> + cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
> + return rc;
> + }
> +
> + return __cifs_calc_signature(rqst, server, signature,
> +      &server->secmech.sdescmd5->shash);
> +}
> +
>  /* must be called with server->srv_mutex held */
>  int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
>      __u32 *pexpected_response_sequence_number)
> diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> index eed7ff5..d9b4f44 100644
> --- a/fs/cifs/cifsproto.h
> +++ b/fs/cifs/cifsproto.h
> @@ -512,4 +512,7 @@ int cifs_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
>      struct cifs_sb_info *cifs_sb,
>      const unsigned char *path, char *pbuf,
>      unsigned int *pbytes_written);
> +int __cifs_calc_signature(struct smb_rqst *rqst,
> + struct TCP_Server_Info *server, char *signature,
> + struct shash_desc *shash);
>  #endif /* _CIFSPROTO_H */
> diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
> index 8732a43..bc9a7b6 100644
> --- a/fs/cifs/smb2transport.c
> +++ b/fs/cifs/smb2transport.c
> @@ -135,11 +135,10 @@ smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
>  int
>  smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>  {
> - int i, rc;
> + int rc;
>   unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
>   unsigned char *sigptr = smb2_signature;
>   struct kvec *iov = rqst->rq_iov;
> - int n_vec = rqst->rq_nvec;
>   struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
>   struct cifs_ses *ses;
>  
> @@ -171,53 +170,11 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>   return rc;
>   }
>  
> - for (i = 0; i < n_vec; i++) {
> - if (iov[i].iov_len == 0)
> - continue;
> - if (iov[i].iov_base == NULL) {
> - cifs_dbg(VFS, "null iovec entry\n");
> - return -EIO;
> - }
> - /*
> -  * The first entry includes a length field (which does not get
> -  * signed that occupies the first 4 bytes before the header).
> -  */
> - if (i == 0) {
> - if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
> - break; /* nothing to sign or corrupt header */
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdeschmacsha256->shash,
> - iov[i].iov_base + 4, iov[i].iov_len - 4);
> - } else {
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdeschmacsha256->shash,
> - iov[i].iov_base, iov[i].iov_len);
> - }
> - if (rc) {
> - cifs_dbg(VFS, "%s: Could not update with payload\n",
> -  __func__);
> - return rc;
> - }
> - }
> -
> - /* now hash over the rq_pages array */
> - for (i = 0; i < rqst->rq_npages; i++) {
> - struct kvec p_iov;
> -
> - cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> - crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
> - p_iov.iov_base, p_iov.iov_len);
> - kunmap(rqst->rq_pages[i]);
> - }
> -
> - rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
> - sigptr);
> - if (rc)
> - cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
> + rc = __cifs_calc_signature(rqst, server, sigptr,
> + &server->secmech.sdeschmacsha256->shash);
>  
> - memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
> + if (!rc)
> + memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
>  
>   return rc;
>  }
> @@ -395,12 +352,10 @@ generate_smb311signingkey(struct cifs_ses *ses)
>  int
>  smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>  {
> - int i;
>   int rc = 0;
>   unsigned char smb3_signature[SMB2_CMACAES_SIZE];
>   unsigned char *sigptr = smb3_signature;
>   struct kvec *iov = rqst->rq_iov;
> - int n_vec = rqst->rq_nvec;
>   struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
>   struct cifs_ses *ses;
>  
> @@ -431,54 +386,12 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
>   cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
>   return rc;
>   }
> +
> + rc = __cifs_calc_signature(rqst, server, sigptr,
> +    &server->secmech.sdesccmacaes->shash);
>  
> - for (i = 0; i < n_vec; i++) {
> - if (iov[i].iov_len == 0)
> - continue;
> - if (iov[i].iov_base == NULL) {
> - cifs_dbg(VFS, "null iovec entry");
> - return -EIO;
> - }
> - /*
> -  * The first entry includes a length field (which does not get
> -  * signed that occupies the first 4 bytes before the header).
> -  */
> - if (i == 0) {
> - if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
> - break; /* nothing to sign or corrupt header */
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdesccmacaes->shash,
> - iov[i].iov_base + 4, iov[i].iov_len - 4);
> - } else {
> - rc =
> - crypto_shash_update(
> - &server->secmech.sdesccmacaes->shash,
> - iov[i].iov_base, iov[i].iov_len);
> - }
> - if (rc) {
> - cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload\n",
> - __func__);
> - return rc;
> - }
> - }
> -
> - /* now hash over the rq_pages array */
> - for (i = 0; i < rqst->rq_npages; i++) {
> - struct kvec p_iov;
> -
> - cifs_rqst_page_to_kvec(rqst, i, &p_iov);
> - crypto_shash_update(&server->secmech.sdesccmacaes->shash,
> - p_iov.iov_base, p_iov.iov_len);
> - kunmap(rqst->rq_pages[i]);
> - }
> -
> - rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
> - sigptr);
> - if (rc)
> - cifs_dbg(VFS, "%s: Could not generate cmac aes\n", __func__);
> -
> - memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
> + if (!rc)
> + memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
>  
>   return rc;
>  }

Nice. Long overdue cleanup.

Reviewed-by: Jeff Layton <jlayton@poochiereds.net>

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