diff mbox series

cifs: clarify SMB1 code for UnixCreateHardLink

Message ID CAH2r5mtHr8eQJo=L1of-PHHNa8iuGUQqWzAAFdpT0=14rvKSkQ@mail.gmail.com
State New
Headers show
Series cifs: clarify SMB1 code for UnixCreateHardLink | expand

Commit Message

Steve French July 1, 2021, 10:53 p.m. UTC 
Coverity complains about the way we calculate the offset
(starting from the address of a 4 byte array within the
header structure rather than from the beginning of the struct
plus 4 bytes).  This doesn't change the address but
makes it slightly clearer.

Addresses-Coverity: 711529 ("Out of bounds read")
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/cifspdu.h | 1 +
 fs/cifs/cifssmb.c | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

  name_len_target =
      cifsConvertToUTF16((__le16 *) data_offset, fromName,

Comments

ronnie sahlberg July 1, 2021, 10:56 p.m. UTC | #1 
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>

On Fri, Jul 2, 2021 at 8:53 AM Steve French <smfrench@gmail.com> wrote:
>
> Coverity complains about the way we calculate the offset
> (starting from the address of a 4 byte array within the
> header structure rather than from the beginning of the struct
> plus 4 bytes).  This doesn't change the address but
> makes it slightly clearer.
>
> Addresses-Coverity: 711529 ("Out of bounds read")
> Signed-off-by: Steve French <stfrench@microsoft.com>
> ---
>  fs/cifs/cifspdu.h | 1 +
>  fs/cifs/cifssmb.c | 3 ++-
>  2 files changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
> index 0923f72d27e9..f6e235001358 100644
> --- a/fs/cifs/cifspdu.h
> +++ b/fs/cifs/cifspdu.h
> @@ -1785,6 +1785,7 @@ struct smb_com_transaction2_sfi_req {
>   __u16 Fid;
>   __le16 InformationLevel;
>   __u16 Reserved4;
> + __u8  payload[];
>  } __attribute__((packed));
>
>  struct smb_com_transaction2_sfi_rsp {
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 58ebec4d4413..ea12fa6eacb6 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -3009,7 +3009,8 @@ CIFSUnixCreateHardLink(const unsigned int xid,
> struct cifs_tcon *tcon,
>   InformationLevel) - 4;
>   offset = param_offset + params;
>
> - data_offset = (char *) (&pSMB->hdr.Protocol) + offset;
> + /* SMB offsets are from the beginning of SMB which is 4 bytes in,
> after RFC1001 field */
> + data_offset = (char *)pSMB + offset + 4;
>   if (pSMB->hdr.Flags2 & SMBFLG2_UNICODE) {
>   name_len_target =
>       cifsConvertToUTF16((__le16 *) data_offset, fromName,
>
> --
> Thanks,
>
> Steve
diff mbox series

Patch

From 16e790b35255c1e70964fd6ee9272bc603614aa1 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Thu, 1 Jul 2021 17:46:23 -0500
Subject: [PATCH] cifs: clarify SMB1 code for UnixCreateHardLink

Coverity complains about the way we calculate the offset
(starting from the address of a 4 byte array within the
header structure rather than from the beginning of the struct
plus 4 bytes).  This doesn't change the address but
makes it slightly clearer.

Addresses-Coverity: 711529 ("Out of bounds read")
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/cifspdu.h | 1 +
 fs/cifs/cifssmb.c | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
index 0923f72d27e9..f6e235001358 100644
--- a/fs/cifs/cifspdu.h
+++ b/fs/cifs/cifspdu.h
@@ -1785,6 +1785,7 @@  struct smb_com_transaction2_sfi_req {
 	__u16 Fid;
 	__le16 InformationLevel;
 	__u16 Reserved4;
+	__u8  payload[];
 } __attribute__((packed));
 
 struct smb_com_transaction2_sfi_rsp {
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 58ebec4d4413..ea12fa6eacb6 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -3009,7 +3009,8 @@  CIFSUnixCreateHardLink(const unsigned int xid, struct cifs_tcon *tcon,
 				InformationLevel) - 4;
 	offset = param_offset + params;
 
-	data_offset = (char *) (&pSMB->hdr.Protocol) + offset;
+	/* SMB offsets are from the beginning of SMB which is 4 bytes in, after RFC1001 field */
+	data_offset = (char *)pSMB + offset + 4;
 	if (pSMB->hdr.Flags2 & SMBFLG2_UNICODE) {
 		name_len_target =
 		    cifsConvertToUTF16((__le16 *) data_offset, fromName,
-- 
2.30.2