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ksmbd: add support for negotiating signing algorithm 

Support for faster packet signing (using GMAC instead of CMAC) can
now be negotiated to some newer servers, including Windows.
See MS-SMB2 section 2.2.3.17.

This patch adds support for sending the new negotiate context with two
supported signing algorithms(AES-CMAC, HMAC-SHA256).
If client add support for AES_GMAC, Server will be supported later
depend on it.

Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Namjae Jeon 2021-07-21 10:05:53 +09:00
parent af320a7390
commit 378087cd17
4 changed files with 78 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/ksmbd/connection.h
View File

@ -109,6 +109,8 @@ struct ksmbd_conn {
__le16 cipher_type;
__le16 compress_algorithm;
bool posix_ext_supported;
bool signing_negotiated;
__le16 signing_algorithm;
bool binding;
};

4
fs/ksmbd/smb2ops.c
View File

@ -204,6 +204,7 @@ void init_smb2_1_server(struct ksmbd_conn *conn)
conn->cmds = smb2_0_server_cmds;
conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
conn->max_credits = SMB2_MAX_CREDITS;
conn->signing_algorithm = SIGNING_ALG_HMAC_SHA256;
if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
conn->vals->capabilities |= SMB2_GLOBAL_CAP_LEASING;
@ -221,6 +222,7 @@ void init_smb3_0_server(struct ksmbd_conn *conn)
conn->cmds = smb2_0_server_cmds;
conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
conn->max_credits = SMB2_MAX_CREDITS;
conn->signing_algorithm = SIGNING_ALG_AES_CMAC;
if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
conn->vals->capabilities |= SMB2_GLOBAL_CAP_LEASING;
@ -245,6 +247,7 @@ void init_smb3_02_server(struct ksmbd_conn *conn)
conn->cmds = smb2_0_server_cmds;
conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
conn->max_credits = SMB2_MAX_CREDITS;
conn->signing_algorithm = SIGNING_ALG_AES_CMAC;
if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
conn->vals->capabilities |= SMB2_GLOBAL_CAP_LEASING;
@ -269,6 +272,7 @@ int init_smb3_11_server(struct ksmbd_conn *conn)
conn->cmds = smb2_0_server_cmds;
conn->max_cmds = ARRAY_SIZE(smb2_0_server_cmds);
conn->max_credits = SMB2_MAX_CREDITS;
conn->signing_algorithm = SIGNING_ALG_AES_CMAC;
if (server_conf.flags & KSMBD_GLOBAL_FLAG_SMB2_LEASES)
conn->vals->capabilities |= SMB2_GLOBAL_CAP_LEASING;

58
fs/ksmbd/smb2pdu.c
View File

@ -786,6 +786,18 @@ static void build_compression_ctxt(struct smb2_compression_ctx *pneg_ctxt,
pneg_ctxt->CompressionAlgorithms[0] = comp_algo;
}
static void build_sign_cap_ctxt(struct smb2_signing_capabilities *pneg_ctxt,
__le16 sign_algo)
{
pneg_ctxt->ContextType = SMB2_SIGNING_CAPABILITIES;
pneg_ctxt->DataLength =
cpu_to_le16((sizeof(struct smb2_signing_capabilities) + 2)
- sizeof(struct smb2_neg_context));
pneg_ctxt->Reserved = cpu_to_le32(0);
pneg_ctxt->SigningAlgorithmCount = cpu_to_le16(1);
pneg_ctxt->SigningAlgorithms[0] = sign_algo;
}
static void build_posix_ctxt(struct smb2_posix_neg_context *pneg_ctxt)
{
pneg_ctxt->ContextType = SMB2_POSIX_EXTENSIONS_AVAILABLE;
@ -863,6 +875,18 @@ static void assemble_neg_contexts(struct ksmbd_conn *conn,
build_posix_ctxt((struct smb2_posix_neg_context *)pneg_ctxt);
rsp->NegotiateContextCount = cpu_to_le16(++neg_ctxt_cnt);
ctxt_size += sizeof(struct smb2_posix_neg_context);
/* Round to 8 byte boundary */
pneg_ctxt += round_up(sizeof(struct smb2_posix_neg_context), 8);
}
if (conn->signing_negotiated) {
ctxt_size = round_up(ctxt_size, 8);
ksmbd_debug(SMB,
"assemble SMB2_SIGNING_CAPABILITIES context\n");
build_sign_cap_ctxt((struct smb2_signing_capabilities *)pneg_ctxt,
conn->signing_algorithm);
rsp->NegotiateContextCount = cpu_to_le16(++neg_ctxt_cnt);
ctxt_size += sizeof(struct smb2_signing_capabilities) + 2;
}
inc_rfc1001_len(rsp, ctxt_size);
@ -919,6 +943,34 @@ static void decode_compress_ctxt(struct ksmbd_conn *conn,
conn->compress_algorithm = SMB3_COMPRESS_NONE;
}
static void decode_sign_cap_ctxt(struct ksmbd_conn *conn,
struct smb2_signing_capabilities *pneg_ctxt,
int len_of_ctxts)
{
int sign_algo_cnt = le16_to_cpu(pneg_ctxt->SigningAlgorithmCount);
int i, sign_alos_size = sign_algo_cnt * sizeof(__le16);
conn->signing_negotiated = false;
if (sizeof(struct smb2_signing_capabilities) + sign_alos_size >
len_of_ctxts) {
pr_err("Invalid signing algorithm count(%d)\n", sign_algo_cnt);
return;
}
for (i = 0; i < sign_algo_cnt; i++) {
if (pneg_ctxt->SigningAlgorithms[i] == SIGNING_ALG_HMAC_SHA256 ||
pneg_ctxt->SigningAlgorithms[i] == SIGNING_ALG_AES_CMAC) {
ksmbd_debug(SMB, "Signing Algorithm ID = 0x%x\n",
pneg_ctxt->SigningAlgorithms[i]);
conn->signing_negotiated = true;
conn->signing_algorithm =
pneg_ctxt->SigningAlgorithms[i];
break;
}
}
}
static __le32 deassemble_neg_contexts(struct ksmbd_conn *conn,
struct smb2_negotiate_req *req)
{
@ -987,6 +1039,12 @@ static __le32 deassemble_neg_contexts(struct ksmbd_conn *conn,
ksmbd_debug(SMB,
"deassemble SMB2_POSIX_EXTENSIONS_AVAILABLE context\n");
conn->posix_ext_supported = true;
} else if (pctx->ContextType == SMB2_SIGNING_CAPABILITIES) {
ksmbd_debug(SMB,
"deassemble SMB2_SIGNING_CAPABILITIES context\n");
decode_sign_cap_ctxt(conn,
(struct smb2_signing_capabilities *)pctx,
len_of_ctxts);
}
/* offsets must be 8 byte aligned */

14
fs/ksmbd/smb2pdu.h
View File

@ -268,6 +268,7 @@ struct preauth_integrity_info {
#define SMB2_ENCRYPTION_CAPABILITIES cpu_to_le16(2)
#define SMB2_COMPRESSION_CAPABILITIES cpu_to_le16(3)
#define SMB2_NETNAME_NEGOTIATE_CONTEXT_ID cpu_to_le16(5)
#define SMB2_SIGNING_CAPABILITIES cpu_to_le16(8)
#define SMB2_POSIX_EXTENSIONS_AVAILABLE cpu_to_le16(0x100)
struct smb2_neg_context {
@ -332,6 +333,19 @@ struct smb2_netname_neg_context {
__le16 NetName[]; /* hostname of target converted to UCS-2 */
} __packed;
/* Signing algorithms */
#define SIGNING_ALG_HMAC_SHA256 cpu_to_le16(0)
#define SIGNING_ALG_AES_CMAC cpu_to_le16(1)
#define SIGNING_ALG_AES_GMAC cpu_to_le16(2)
struct smb2_signing_capabilities {
__le16 ContextType; /* 8 */
__le16 DataLength;
__le32 Reserved;
__le16 SigningAlgorithmCount;
__le16 SigningAlgorithms[];
} __packed;
struct smb2_negotiate_rsp {
struct smb2_hdr hdr;
__le16 StructureSize; /* Must be 65 */