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cifs: Use data structures to compute NTLMv2 response offsets

A bit of cleanup plus some gratuitous variable renaming. I think using
structures instead of numeric offsets makes this code much more
understandable.

Also added a comment about current time range expected by
the server.

Acked-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Steve French <smfrench@gmail.com>
master
Tim Gardner 8 years ago
committed by Steve French
parent
commit
2c957ddf30
  1. 40
      fs/cifs/cifsencrypt.c
  2. 8
      fs/cifs/cifspdu.h

40
fs/cifs/cifsencrypt.c

@ -548,7 +548,13 @@ static int
CalcNTLMv2_response(const struct cifs_ses *ses, char *ntlmv2_hash)
{
int rc;
unsigned int offset = CIFS_SESS_KEY_SIZE + 8;
struct ntlmv2_resp *ntlmv2 = (struct ntlmv2_resp *)
(ses->auth_key.response + CIFS_SESS_KEY_SIZE);
unsigned int hash_len;
/* The MD5 hash starts at challenge_key.key */
hash_len = ses->auth_key.len - (CIFS_SESS_KEY_SIZE +
offsetof(struct ntlmv2_resp, challenge.key[0]));
if (!ses->server->secmech.sdeschmacmd5) {
cifs_dbg(VFS, "%s: can't generate ntlmv2 hash\n", __func__);
@ -556,7 +562,7 @@ CalcNTLMv2_response(const struct cifs_ses *ses, char *ntlmv2_hash)
}
rc = crypto_shash_setkey(ses->server->secmech.hmacmd5,
ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
ntlmv2_hash, CIFS_HMAC_MD5_HASH_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not set NTLMV2 Hash as a key\n",
__func__);
@ -570,20 +576,21 @@ CalcNTLMv2_response(const struct cifs_ses *ses, char *ntlmv2_hash)
}
if (ses->server->negflavor == CIFS_NEGFLAVOR_EXTENDED)
memcpy(ses->auth_key.response + offset,
ses->ntlmssp->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
memcpy(ntlmv2->challenge.key,
ses->ntlmssp->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
else
memcpy(ses->auth_key.response + offset,
ses->server->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
memcpy(ntlmv2->challenge.key,
ses->server->cryptkey, CIFS_SERVER_CHALLENGE_SIZE);
rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
ses->auth_key.response + offset, ses->auth_key.len - offset);
ntlmv2->challenge.key, hash_len);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
return rc;
}
/* Note that the MD5 digest over writes anon.challenge_key.key */
rc = crypto_shash_final(&ses->server->secmech.sdeschmacmd5->shash,
ses->auth_key.response + CIFS_SESS_KEY_SIZE);
ntlmv2->ntlmv2_hash);
if (rc)
cifs_dbg(VFS, "%s: Could not generate md5 hash\n", __func__);
@ -627,7 +634,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
int rc;
int baselen;
unsigned int tilen;
struct ntlmv2_resp *buf;
struct ntlmv2_resp *ntlmv2;
char ntlmv2_hash[16];
unsigned char *tiblob = NULL; /* target info blob */
@ -660,13 +667,14 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
}
ses->auth_key.len += baselen;
buf = (struct ntlmv2_resp *)
ntlmv2 = (struct ntlmv2_resp *)
(ses->auth_key.response + CIFS_SESS_KEY_SIZE);
buf->blob_signature = cpu_to_le32(0x00000101);
buf->reserved = 0;
buf->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
get_random_bytes(&buf->client_chal, sizeof(buf->client_chal));
buf->reserved2 = 0;
ntlmv2->blob_signature = cpu_to_le32(0x00000101);
ntlmv2->reserved = 0;
/* Must be within 5 minutes of the server */
ntlmv2->time = cpu_to_le64(cifs_UnixTimeToNT(CURRENT_TIME));
get_random_bytes(&ntlmv2->client_chal, sizeof(ntlmv2->client_chal));
ntlmv2->reserved2 = 0;
memcpy(ses->auth_key.response + baselen, tiblob, tilen);
@ -706,7 +714,7 @@ setup_ntlmv2_rsp(struct cifs_ses *ses, const struct nls_table *nls_cp)
}
rc = crypto_shash_update(&ses->server->secmech.sdeschmacmd5->shash,
ses->auth_key.response + CIFS_SESS_KEY_SIZE,
ntlmv2->ntlmv2_hash,
CIFS_HMAC_MD5_HASH_SIZE);
if (rc) {
cifs_dbg(VFS, "%s: Could not update with response\n", __func__);

8
fs/cifs/cifspdu.h

@ -697,7 +697,13 @@ struct ntlmssp2_name {
} __attribute__((packed));
struct ntlmv2_resp {
char ntlmv2_hash[CIFS_ENCPWD_SIZE];
union {
char ntlmv2_hash[CIFS_ENCPWD_SIZE];
struct {
__u8 reserved[8];
__u8 key[CIFS_SERVER_CHALLENGE_SIZE];
} __attribute__((packed)) challenge;
} __attribute__((packed));
__le32 blob_signature;
__u32 reserved;
__le64 time;

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