smb3: Replace smb2pdu 1-element arrays with flex-arrays
authorKees Cook <keescook@chromium.org>
Fri, 26 Jan 2024 19:31:43 +0000 (22:31 +0300)
committerSalvatore Bonaccorso <carnil@debian.org>
Wed, 31 Jan 2024 21:14:09 +0000 (22:14 +0100)
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit?id=06aa6eff7b243891c631b40852a0c453e274955d

commit eb3e28c1e89b4984308777231887e41aa8a0151f upstream.

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>
Signed-off-by: Vasiliy Kovalev <kovalev@altlinux.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name smb3-Replace-smb2pdu-1-element-arrays-with-flex-arra.patch

fs/cifs/smb2misc.c
fs/cifs/smb2ops.c
fs/cifs/smb2pdu.c
fs/cifs/smb2pdu.h

index b98bba887f84b0ab0a4145eaaf21de7de6332bb7..660e00eb42060ac4798aa22d61bbf979c2b1cce4 100644 (file)
@@ -117,7 +117,7 @@ static __u32 get_neg_ctxt_len(struct smb2_sync_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
index 26edaeb4245d8c315aea4a06528302405e3881cf..84850a55c8b7e70ac875c6a9e152d2d613d6b69a 100644 (file)
@@ -5561,7 +5561,7 @@ struct smb_version_values smb20_values = {
        .header_size = sizeof(struct smb2_sync_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,
@@ -5583,7 +5583,7 @@ struct smb_version_values smb21_values = {
        .header_size = sizeof(struct smb2_sync_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,
@@ -5604,7 +5604,7 @@ struct smb_version_values smb3any_values = {
        .header_size = sizeof(struct smb2_sync_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,
@@ -5625,7 +5625,7 @@ struct smb_version_values smbdefault_values = {
        .header_size = sizeof(struct smb2_sync_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,
@@ -5646,7 +5646,7 @@ struct smb_version_values smb30_values = {
        .header_size = sizeof(struct smb2_sync_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 smb302_values = {
        .header_size = sizeof(struct smb2_sync_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 smb311_values = {
        .header_size = sizeof(struct smb2_sync_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,
index 76679dc4e63288643580079de5fe7eb65a141145..4aec01841f0f26ceb3e872169578a0b5ede4c530 100644 (file)
@@ -1261,7 +1261,7 @@ 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));
@@ -1760,8 +1760,7 @@ 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 - 2);
        iov[1].iov_base = unc_path;
        iov[1].iov_len = unc_path_len;
@@ -4676,7 +4675,7 @@ 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
@@ -4873,7 +4872,7 @@ SMB2_set_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
        req->AdditionalInformation = cpu_to_le32(additional_info);
 
        req->BufferOffset =
-                       cpu_to_le16(sizeof(struct smb2_set_info_req) - 1);
+                       cpu_to_le16(sizeof(struct smb2_set_info_req));
        req->BufferLength = cpu_to_le32(*size);
 
        memcpy(req->Buffer, *data, *size);
@@ -5105,9 +5104,9 @@ 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;
index 89a732b31390ea505ea1a72d3f13f9b5fd5cdb29..eaa873175318a0cd569fd8233354b5c88e230909 100644 (file)
@@ -220,7 +220,7 @@ struct smb2_err_rsp {
        __le16 StructureSize;
        __le16 Reserved; /* MBZ */
        __le32 ByteCount;  /* even if zero, at least one byte follows */
-       __u8   ErrorData[1];  /* variable length */
+       __u8   ErrorData[];  /* variable length */
 } __packed;
 
 #define SYMLINK_ERROR_TAG 0x4c4d5953
@@ -464,7 +464,7 @@ 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;
 
 /* Flags */
@@ -481,7 +481,7 @@ struct smb2_sess_setup_req {
        __le16 SecurityBufferOffset;
        __le16 SecurityBufferLength;
        __u64 PreviousSessionId;
-       __u8   Buffer[1];       /* variable length GSS security buffer */
+       __u8   Buffer[];        /* variable length GSS security buffer */
 } __packed;
 
 /* Currently defined SessionFlags */
@@ -494,7 +494,7 @@ 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;
 
 struct smb2_logoff_req {
@@ -520,7 +520,7 @@ struct smb2_tree_connect_req {
        __le16 Flags; /* Reserved MBZ for dialects prior to SMB3.1.1 */
        __le16 PathOffset;
        __le16 PathLength;
-       __u8   Buffer[1];       /* variable length */
+       __u8   Buffer[];        /* variable length */
 } __packed;
 
 /* See MS-SMB2 section 2.2.9.2 */
@@ -828,7 +828,7 @@ struct smb2_create_rsp {
        __u64  VolatileFileId; /* opaque endianness */
        __le32 CreateContextsOffset;
        __le32 CreateContextsLength;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 struct create_context {
@@ -1289,7 +1289,7 @@ struct smb2_read_plain_req {
        __le32 RemainingBytes;
        __le16 ReadChannelInfoOffset;
        __le16 ReadChannelInfoLength;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 /* Read flags */
@@ -1304,7 +1304,7 @@ struct smb2_read_rsp {
        __le32 DataLength;
        __le32 DataRemaining;
        __u32  Flags;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 /* For write request Flags field below the following flags are defined: */
@@ -1324,7 +1324,7 @@ struct smb2_write_req {
        __le16 WriteChannelInfoOffset;
        __le16 WriteChannelInfoLength;
        __le32 Flags;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 struct smb2_write_rsp {
@@ -1335,7 +1335,7 @@ struct smb2_write_rsp {
        __le32 DataLength;
        __le32 DataRemaining;
        __u32  Reserved2;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 /* notify flags */
@@ -1371,7 +1371,7 @@ 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;
 
 #define SMB2_LOCKFLAG_SHARED_LOCK      0x0001
@@ -1394,7 +1394,10 @@ struct smb2_lock_req {
        __u64  PersistentFileId; /* opaque endianness */
        __u64  VolatileFileId; /* opaque endianness */
        /* 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 {
@@ -1434,7 +1437,7 @@ struct smb2_query_directory_req {
        __le16 FileNameOffset;
        __le16 FileNameLength;
        __le32 OutputBufferLength;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 struct smb2_query_directory_rsp {
@@ -1442,7 +1445,7 @@ struct smb2_query_directory_rsp {
        __le16 StructureSize; /* Must be 9 */
        __le16 OutputBufferOffset;
        __le32 OutputBufferLength;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 /* Possible InfoType values */
@@ -1483,7 +1486,7 @@ struct smb2_query_info_req {
        __le32 Flags;
        __u64  PersistentFileId; /* opaque endianness */
        __u64  VolatileFileId; /* opaque endianness */
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 struct smb2_query_info_rsp {
@@ -1491,7 +1494,7 @@ struct smb2_query_info_rsp {
        __le16 StructureSize; /* Must be 9 */
        __le16 OutputBufferOffset;
        __le32 OutputBufferLength;
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 /*
@@ -1514,7 +1517,7 @@ struct smb2_set_info_req {
        __le32 AdditionalInformation;
        __u64  PersistentFileId; /* opaque endianness */
        __u64  VolatileFileId; /* opaque endianness */
-       __u8   Buffer[1];
+       __u8   Buffer[];
 } __packed;
 
 struct smb2_set_info_rsp {
@@ -1716,7 +1719,10 @@ 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 */