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smb3: Replace smb2pdu 1-element arrays with flex-arrays 

The kernel is globally removing the ambiguous 0-length and 1-element
arrays in favor of flexible arrays, so that we can gain both compile-time
and run-time array bounds checking[1].

Replace the trailing 1-element array with a flexible array in the
following structures:

	struct smb2_err_rsp
	struct smb2_tree_connect_req
	struct smb2_negotiate_rsp
	struct smb2_sess_setup_req
	struct smb2_sess_setup_rsp
	struct smb2_read_req
	struct smb2_read_rsp
	struct smb2_write_req
	struct smb2_write_rsp
	struct smb2_query_directory_req
	struct smb2_query_directory_rsp
	struct smb2_set_info_req
	struct smb2_change_notify_rsp
	struct smb2_create_rsp
	struct smb2_query_info_req
	struct smb2_query_info_rsp

Replace the trailing 1-element array with a flexible array, but leave
the existing structure padding:

	struct smb2_file_all_info
	struct smb2_lock_req

Adjust all related size calculations to match the changes to sizeof().

No machine code output or .data section differences are produced after
these changes.

[1] For lots of details, see both:
    https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays
    https://people.kernel.org/kees/bounded-flexible-arrays-in-c

Cc: Steve French <sfrench@samba.org>
Cc: Paulo Alcantara <pc@cjr.nz>
Cc: Ronnie Sahlberg <lsahlber@redhat.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Kees Cook 2023-02-17 16:24:40 -08:00 committed by Steve French
parent 0e9bd27b2a
commit eb3e28c1e8
8 changed files with 47 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/cifs/smb2file.c
View File

@ -34,7 +34,7 @@ static struct smb2_symlink_err_rsp *symlink_data(const struct kvec *iov)
len = (u32)err->ErrorContextCount * (offsetof(struct smb2_error_context_rsp,
ErrorContextData) +
sizeof(struct smb2_symlink_err_rsp));
if (le32_to_cpu(err->ByteCount) < len || iov->iov_len < len + sizeof(*err))
if (le32_to_cpu(err->ByteCount) < len || iov->iov_len < len + sizeof(*err) + 1)
return ERR_PTR(-EINVAL);
p = (struct smb2_error_context_rsp *)err->ErrorData;

2
fs/cifs/smb2misc.c
View File

@ -113,7 +113,7 @@ static __u32 get_neg_ctxt_len(struct smb2_hdr *hdr, __u32 len,
} else if (nc_offset + 1 == non_ctxlen) {
cifs_dbg(FYI, "no SPNEGO security blob in negprot rsp\n");
size_of_pad_before_neg_ctxts = 0;
} else if (non_ctxlen == SMB311_NEGPROT_BASE_SIZE)
} else if (non_ctxlen == SMB311_NEGPROT_BASE_SIZE + 1)
/* has padding, but no SPNEGO blob */
size_of_pad_before_neg_ctxts = nc_offset - non_ctxlen + 1;
else

14
fs/cifs/smb2ops.c
View File

@ -5645,7 +5645,7 @@ struct smb_version_values smb20_values = {
.header_size = sizeof(struct smb2_hdr),
.header_preamble_size = 0,
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -5667,7 +5667,7 @@ struct smb_version_values smb21_values = {
.header_size = sizeof(struct smb2_hdr),
.header_preamble_size = 0,
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -5688,7 +5688,7 @@ struct smb_version_values smb3any_values = {
.header_size = sizeof(struct smb2_hdr),
.header_preamble_size = 0,
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -5709,7 +5709,7 @@ struct smb_version_values smbdefault_values = {
.header_size = sizeof(struct smb2_hdr),
.header_preamble_size = 0,
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -5730,7 +5730,7 @@ struct smb_version_values smb30_values = {
.header_size = sizeof(struct smb2_hdr),
.header_preamble_size = 0,
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -5751,7 +5751,7 @@ struct smb_version_values smb302_values = {
.header_size = sizeof(struct smb2_hdr),
.header_preamble_size = 0,
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -5772,7 +5772,7 @@ struct smb_version_values smb311_values = {
.header_size = sizeof(struct smb2_hdr),
.header_preamble_size = 0,
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,

16
fs/cifs/smb2pdu.c
View File

@ -1373,7 +1373,7 @@ SMB2_sess_sendreceive(struct SMB2_sess_data *sess_data)
/* Testing shows that buffer offset must be at location of Buffer[0] */
req->SecurityBufferOffset =
cpu_to_le16(sizeof(struct smb2_sess_setup_req) - 1 /* pad */);
cpu_to_le16(sizeof(struct smb2_sess_setup_req));
req->SecurityBufferLength = cpu_to_le16(sess_data->iov[1].iov_len);
memset(&rqst, 0, sizeof(struct smb_rqst));
@ -1892,8 +1892,7 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
iov[0].iov_len = total_len - 1;
/* Testing shows that buffer offset must be at location of Buffer[0] */
req->PathOffset = cpu_to_le16(sizeof(struct smb2_tree_connect_req)
- 1 /* pad */);
req->PathOffset = cpu_to_le16(sizeof(struct smb2_tree_connect_req));
req->PathLength = cpu_to_le16(unc_path_len);
iov[1].iov_base = unc_path;
iov[1].iov_len = unc_path_len;
@ -3773,7 +3772,7 @@ SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
ses->Suid, (u8)watch_tree, completion_filter);
/* validate that notify information is plausible */
if ((rsp_iov.iov_base == NULL) ||
(rsp_iov.iov_len < sizeof(struct smb2_change_notify_rsp)))
(rsp_iov.iov_len < sizeof(struct smb2_change_notify_rsp) + 1))
goto cnotify_exit;
smb_rsp = (struct smb2_change_notify_rsp *)rsp_iov.iov_base;
@ -4966,7 +4965,7 @@ int SMB2_query_directory_init(const unsigned int xid,
memcpy(bufptr, &asteriks, len);
req->FileNameOffset =
cpu_to_le16(sizeof(struct smb2_query_directory_req) - 1);
cpu_to_le16(sizeof(struct smb2_query_directory_req));
req->FileNameLength = cpu_to_le16(len);
/*
* BB could be 30 bytes or so longer if we used SMB2 specific
@ -5162,8 +5161,7 @@ SMB2_set_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
req->VolatileFileId = volatile_fid;
req->AdditionalInformation = cpu_to_le32(additional_info);
req->BufferOffset =
cpu_to_le16(sizeof(struct smb2_set_info_req) - 1);
req->BufferOffset = cpu_to_le16(sizeof(struct smb2_set_info_req));
req->BufferLength = cpu_to_le32(*size);
memcpy(req->Buffer, *data, *size);
@ -5397,9 +5395,9 @@ build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon,
req->VolatileFileId = volatile_fid;
/* 1 for pad */
req->InputBufferOffset =
cpu_to_le16(sizeof(struct smb2_query_info_req) - 1);
cpu_to_le16(sizeof(struct smb2_query_info_req));
req->OutputBufferLength = cpu_to_le32(
outbuf_len + sizeof(struct smb2_query_info_rsp) - 1);
outbuf_len + sizeof(struct smb2_query_info_rsp));
iov->iov_base = (char *)req;
iov->iov_len = total_len;

2
fs/cifs/smb2pdu.h
View File

@ -57,7 +57,7 @@ struct smb2_rdma_crypto_transform {
#define COMPOUND_FID 0xFFFFFFFFFFFFFFFFULL
#define SMB2_SYMLINK_STRUCT_SIZE \
(sizeof(struct smb2_err_rsp) - 1 + sizeof(struct smb2_symlink_err_rsp))
(sizeof(struct smb2_err_rsp) + sizeof(struct smb2_symlink_err_rsp))
#define SYMLINK_ERROR_TAG 0x4c4d5953

8
fs/ksmbd/smb2ops.c
View File

@ -26,7 +26,7 @@ static struct smb_version_values smb21_server_values = {
.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
.header_size = sizeof(struct smb2_hdr),
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -52,7 +52,7 @@ static struct smb_version_values smb30_server_values = {
.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
.header_size = sizeof(struct smb2_hdr),
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -79,7 +79,7 @@ static struct smb_version_values smb302_server_values = {
.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
.header_size = sizeof(struct smb2_hdr),
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,
@ -106,7 +106,7 @@ static struct smb_version_values smb311_server_values = {
.unlock_lock_type = SMB2_LOCKFLAG_UNLOCK,
.header_size = sizeof(struct smb2_hdr),
.max_header_size = MAX_SMB2_HDR_SIZE,
.read_rsp_size = sizeof(struct smb2_read_rsp) - 1,
.read_rsp_size = sizeof(struct smb2_read_rsp),
.lock_cmd = SMB2_LOCK,
.cap_unix = 0,
.cap_nt_find = SMB2_NT_FIND,

6
fs/ksmbd/smb2pdu.c
View File

@ -280,8 +280,7 @@ int init_smb2_neg_rsp(struct ksmbd_work *work)
le16_to_cpu(rsp->SecurityBufferOffset));
inc_rfc1001_len(work->response_buf,
sizeof(struct smb2_negotiate_rsp) -
sizeof(struct smb2_hdr) - sizeof(rsp->Buffer) +
AUTH_GSS_LENGTH);
sizeof(struct smb2_hdr) + AUTH_GSS_LENGTH);
rsp->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED_LE;
if (server_conf.signing == KSMBD_CONFIG_OPT_MANDATORY)
rsp->SecurityMode |= SMB2_NEGOTIATE_SIGNING_REQUIRED_LE;
@ -1212,8 +1211,7 @@ int smb2_handle_negotiate(struct ksmbd_work *work)
ksmbd_copy_gss_neg_header((char *)(&rsp->hdr) +
le16_to_cpu(rsp->SecurityBufferOffset));
inc_rfc1001_len(work->response_buf, sizeof(struct smb2_negotiate_rsp) -
sizeof(struct smb2_hdr) - sizeof(rsp->Buffer) +
AUTH_GSS_LENGTH);
sizeof(struct smb2_hdr) + AUTH_GSS_LENGTH);
rsp->SecurityMode = SMB2_NEGOTIATE_SIGNING_ENABLED_LE;
conn->use_spnego = true;

42
fs/smbfs_common/smb2pdu.h
View File

@ -167,7 +167,7 @@ struct smb2_err_rsp {
__u8 ErrorContextCount;
__u8 Reserved;
__le32 ByteCount; /* even if zero, at least one byte follows */
__u8 ErrorData[1]; /* variable length */
__u8 ErrorData[]; /* variable length */
} __packed;
#define SMB3_AES_CCM_NONCE 11
@ -308,7 +308,7 @@ struct smb2_tree_connect_req {
__le16 Flags; /* Flags in SMB3.1.1 */
__le16 PathOffset;
__le16 PathLength;
__u8 Buffer[1]; /* variable length */
__u8 Buffer[]; /* variable length */
} __packed;
/* Possible ShareType values */
@ -595,7 +595,7 @@ struct smb2_negotiate_rsp {
__le16 SecurityBufferOffset;
__le16 SecurityBufferLength;
__le32 NegotiateContextOffset; /* Pre:SMB3.1.1 was reserved/ignored */
__u8 Buffer[1]; /* variable length GSS security buffer */
__u8 Buffer[]; /* variable length GSS security buffer */
} __packed;
@ -616,7 +616,7 @@ struct smb2_sess_setup_req {
__le16 SecurityBufferOffset;
__le16 SecurityBufferLength;
__le64 PreviousSessionId;
__u8 Buffer[1]; /* variable length GSS security buffer */
__u8 Buffer[]; /* variable length GSS security buffer */
} __packed;
/* Currently defined SessionFlags */
@ -633,7 +633,7 @@ struct smb2_sess_setup_rsp {
__le16 SessionFlags;
__le16 SecurityBufferOffset;
__le16 SecurityBufferLength;
__u8 Buffer[1]; /* variable length GSS security buffer */
__u8 Buffer[]; /* variable length GSS security buffer */
} __packed;
@ -715,7 +715,7 @@ struct smb2_read_req {
__le32 RemainingBytes;
__le16 ReadChannelInfoOffset;
__le16 ReadChannelInfoLength;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
/* Read flags */
@ -730,7 +730,7 @@ struct smb2_read_rsp {
__le32 DataLength;
__le32 DataRemaining;
__le32 Flags;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
@ -754,7 +754,7 @@ struct smb2_write_req {
__le16 WriteChannelInfoOffset;
__le16 WriteChannelInfoLength;
__le32 Flags;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
struct smb2_write_rsp {
@ -765,7 +765,7 @@ struct smb2_write_rsp {
__le32 DataLength;
__le32 DataRemaining;
__u32 Reserved2;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
@ -812,7 +812,10 @@ struct smb2_lock_req {
__u64 PersistentFileId;
__u64 VolatileFileId;
/* Followed by at least one */
struct smb2_lock_element locks[1];
union {
struct smb2_lock_element lock;
DECLARE_FLEX_ARRAY(struct smb2_lock_element, locks);
};
} __packed;
struct smb2_lock_rsp {
@ -866,7 +869,7 @@ struct smb2_query_directory_req {
__le16 FileNameOffset;
__le16 FileNameLength;
__le32 OutputBufferLength;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
struct smb2_query_directory_rsp {
@ -874,7 +877,7 @@ struct smb2_query_directory_rsp {
__le16 StructureSize; /* Must be 9 */
__le16 OutputBufferOffset;
__le32 OutputBufferLength;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
/*
@ -897,7 +900,7 @@ struct smb2_set_info_req {
__le32 AdditionalInformation;
__u64 PersistentFileId;
__u64 VolatileFileId;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
struct smb2_set_info_rsp {
@ -952,7 +955,7 @@ struct smb2_change_notify_rsp {
__le16 StructureSize; /* Must be 9 */
__le16 OutputBufferOffset;
__le32 OutputBufferLength;
__u8 Buffer[1]; /* array of file notify structs */
__u8 Buffer[]; /* array of file notify structs */
} __packed;
@ -1158,7 +1161,7 @@ struct smb2_create_rsp {
__u64 VolatileFileId;
__le32 CreateContextsOffset;
__le32 CreateContextsLength;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
struct create_posix {
@ -1501,7 +1504,7 @@ struct smb2_query_info_req {
__le32 Flags;
__u64 PersistentFileId;
__u64 VolatileFileId;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
struct smb2_query_info_rsp {
@ -1509,7 +1512,7 @@ struct smb2_query_info_rsp {
__le16 StructureSize; /* Must be 9 */
__le16 OutputBufferOffset;
__le32 OutputBufferLength;
__u8 Buffer[1];
__u8 Buffer[];
} __packed;
/*
@ -1570,7 +1573,10 @@ struct smb2_file_all_info { /* data block encoding of response to level 18 */
__le32 Mode;
__le32 AlignmentRequirement;
__le32 FileNameLength;
char FileName[1];
union {
char __pad; /* Legacy structure padding */
DECLARE_FLEX_ARRAY(char, FileName);
};
} __packed; /* level 18 Query */
struct smb2_file_eof_info { /* encoding of request for level 10 */