diff options
| author | Paulo Alcantara <paulo@paulo.ac> | 2018-06-23 20:52:23 +0300 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2018-07-05 21:48:24 +0300 |
| commit | 27c32b49c3dbfe1e5f57d2b61823bf9474ae0875 (patch) | |
| tree | 1a520e0ee9a1a4cb5e49c06f3c3c825b0bc3b83d | |
| parent | 696e420bb2a6624478105651d5368d45b502b324 (diff) | |
| download | linux-27c32b49c3dbfe1e5f57d2b61823bf9474ae0875.tar.xz | |
cifs: Fix validation of signed data in smb3+
Fixes: c713c8770fa5 ("cifs: push rfc1002 generation down the stack")
We failed to validate signed data returned by the server because
__cifs_calc_signature() now expects to sign the actual data in iov but
we were also passing down the rfc1002 length.
Fix smb3_calc_signature() to calculate signature of rfc1002 length prior
to passing only the actual data iov[1-N] to __cifs_calc_signature(). In
addition, there are a few cases where no rfc1002 length is passed so we
make sure there's one (iov_len == 4).
Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
| -rw-r--r-- | fs/cifs/smb2transport.c | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c index 50592976dcb4..1af46ca5a951 100644 --- a/fs/cifs/smb2transport.c +++ b/fs/cifs/smb2transport.c @@ -408,12 +408,14 @@ generate_smb311signingkey(struct cifs_ses *ses) int smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server) { - int rc = 0; + int rc; unsigned char smb3_signature[SMB2_CMACAES_SIZE]; unsigned char *sigptr = smb3_signature; struct kvec *iov = rqst->rq_iov; struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[0].iov_base; struct cifs_ses *ses; + struct shash_desc *shash = &server->secmech.sdesccmacaes->shash; + struct smb_rqst drqst; ses = smb2_find_smb_ses(server, shdr->SessionId); if (!ses) { @@ -425,8 +427,7 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server) memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE); rc = crypto_shash_setkey(server->secmech.cmacaes, - ses->smb3signingkey, SMB2_CMACAES_SIZE); - + ses->smb3signingkey, SMB2_CMACAES_SIZE); if (rc) { cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__); return rc; @@ -437,15 +438,33 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server) * so unlike smb2 case we do not have to check here if secmech are * initialized */ - rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash); + rc = crypto_shash_init(shash); if (rc) { 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 SMB2+, __cifs_calc_signature() expects to sign only the actual + * data, that is, iov[0] should not contain a rfc1002 length. + * + * Sign the rfc1002 length prior to passing the data (iov[1-N]) down to + * __cifs_calc_signature(). + */ + 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_dbg(VFS, "%s: Could not update with payload\n", + __func__); + return rc; + } + drqst.rq_iov++; + drqst.rq_nvec--; + } + rc = __cifs_calc_signature(&drqst, server, sigptr, shash); if (!rc) memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE); |