From: Kees Cook keescook@chromium.org

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-... 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 --- fs/cifs/smb2misc.c | 2 +- fs/cifs/smb2ops.c | 14 +++++++------- fs/cifs/smb2pdu.c | 13 ++++++------- fs/cifs/smb2pdu.h | 42 ++++++++++++++++++++++++------------------ 4 files changed, 38 insertions(+), 33 deletions(-)

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c index e2f401c8c5ce71..8f409404aee1e2 100644 --- a/fs/cifs/smb2misc.c +++ b/fs/cifs/smb2misc.c @@ -113,7 +113,7 @@ 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 diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index f31da2647d042c..f8847546d6ac95 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -5826,7 +5826,7 @@ 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, @@ -5848,7 +5848,7 @@ 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, @@ -5869,7 +5869,7 @@ 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, @@ -5890,7 +5890,7 @@ 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, @@ -5911,7 +5911,7 @@ 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, @@ -5932,7 +5932,7 @@ 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, @@ -5953,7 +5953,7 @@ 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, diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 6714e9db0ee837..a21eeb23f8e1c0 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -1327,7 +1327,7 @@ 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)); @@ -1826,8 +1826,7 @@ 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; @@ -4748,7 +4747,7 @@ 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 @@ -4945,7 +4944,7 @@ 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); @@ -5177,9 +5176,9 @@ 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; diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h index 301c155c526779..812a1b564fb209 100644 --- a/fs/cifs/smb2pdu.h +++ b/fs/cifs/smb2pdu.h @@ -218,7 +218,7 @@ 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 @@ -487,7 +487,7 @@ 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 */ @@ -504,7 +504,7 @@ 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 */ @@ -517,7 +517,7 @@ 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 { @@ -543,7 +543,7 @@ 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 */ @@ -852,7 +852,7 @@ struct smb2_create_rsp { __u64 VolatileFileId; /* opaque endianness */ __le32 CreateContextsOffset; __le32 CreateContextsLength; - __u8 Buffer[1]; + __u8 Buffer[]; } __packed;

struct create_context { @@ -1313,7 +1313,7 @@ struct smb2_read_plain_req { __le32 RemainingBytes; __le16 ReadChannelInfoOffset; __le16 ReadChannelInfoLength; - __u8 Buffer[1]; + __u8 Buffer[]; } __packed;

/* Read flags */ @@ -1328,7 +1328,7 @@ 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: */ @@ -1348,7 +1348,7 @@ struct smb2_write_req { __le16 WriteChannelInfoOffset; __le16 WriteChannelInfoLength; __le32 Flags; - __u8 Buffer[1]; + __u8 Buffer[]; } __packed;

struct smb2_write_rsp { @@ -1359,7 +1359,7 @@ struct smb2_write_rsp { __le32 DataLength; __le32 DataRemaining; __u32 Reserved2; - __u8 Buffer[1]; + __u8 Buffer[]; } __packed;

/* notify flags */ @@ -1395,7 +1395,7 @@ 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 @@ -1422,7 +1422,10 @@ 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 { @@ -1478,7 +1481,7 @@ struct smb2_query_directory_req { __le16 FileNameOffset; __le16 FileNameLength; __le32 OutputBufferLength; - __u8 Buffer[1]; + __u8 Buffer[]; } __packed;

struct smb2_query_directory_rsp { @@ -1486,7 +1489,7 @@ struct smb2_query_directory_rsp { __le16 StructureSize; /* Must be 9 */ __le16 OutputBufferOffset; __le32 OutputBufferLength; - __u8 Buffer[1]; + __u8 Buffer[]; } __packed;

/* Possible InfoType values */ @@ -1527,7 +1530,7 @@ 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 { @@ -1535,7 +1538,7 @@ struct smb2_query_info_rsp { __le16 StructureSize; /* Must be 9 */ __le16 OutputBufferOffset; __le32 OutputBufferLength; - __u8 Buffer[1]; + __u8 Buffer[]; } __packed;

/* @@ -1558,7 +1561,7 @@ 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 { @@ -1761,7 +1764,10 @@ 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 */