From eb3e28c1e89b4984308777231887e41aa8a0151f Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Fri, 17 Feb 2023 16:24:40 -0800 Subject: [PATCH] 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 Cc: Paulo Alcantara Cc: Ronnie Sahlberg Cc: Shyam Prasad N Cc: Tom Talpey Cc: Namjae Jeon Cc: Sergey Senozhatsky Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Reviewed-by: Namjae Jeon Signed-off-by: Kees Cook Signed-off-by: Steve French --- fs/cifs/smb2file.c | 2 +- fs/cifs/smb2misc.c | 2 +- fs/cifs/smb2ops.c | 14 +++++++------- fs/cifs/smb2pdu.c | 16 +++++++--------- fs/cifs/smb2pdu.h | 2 +- fs/ksmbd/smb2ops.c | 8 ++++---- fs/ksmbd/smb2pdu.c | 6 ++---- fs/smbfs_common/smb2pdu.h | 42 ++++++++++++++++++++++++------------------ 8 files changed, 47 insertions(+), 45 deletions(-) diff --git a/fs/cifs/smb2file.c b/fs/cifs/smb2file.c index ba6cc50..a7475bc 100644 --- a/fs/cifs/smb2file.c +++ b/fs/cifs/smb2file.c @@ -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; diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c index 572293c..3935a60 100644 --- a/fs/cifs/smb2misc.c +++ b/fs/cifs/smb2misc.c @@ -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 diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 43beec5..3fea942 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -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, diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 3bc0aa8..4982f5e 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -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; diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h index 3ad7ec4..2114e8a 100644 --- a/fs/cifs/smb2pdu.h +++ b/fs/cifs/smb2pdu.h @@ -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 diff --git a/fs/ksmbd/smb2ops.c b/fs/ksmbd/smb2ops.c index e401302..aed7704 100644 --- a/fs/ksmbd/smb2ops.c +++ b/fs/ksmbd/smb2ops.c @@ -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, diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index d681f91..91fe499 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -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; diff --git a/fs/smbfs_common/smb2pdu.h b/fs/smbfs_common/smb2pdu.h index 7d605db..ace133c 100644 --- a/fs/smbfs_common/smb2pdu.h +++ b/fs/smbfs_common/smb2pdu.h @@ -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 */ -- 2.7.4