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From: Steve French <smfrench@gmail.com>
Date: Tue, 23 Apr 2024 13:57:29 -0500
Message-ID: <CAH2r5mt2gwyyAqotBv5U1esJQggGUbz8_J=6k_Z69X2dRRK8Ug@mail.gmail.com>
Subject: Re: [PATCH AUTOSEL 6.1 15/17] smb: client, common: fix fortify warnings
To: Sasha Levin <sashal@kernel.org>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, 
	Dmitry Antipov <dmantipov@yandex.ru>, Namjae Jeon <linkinjeon@kernel.org>, 
	Steve French <stfrench@microsoft.com>, sfrench@samba.org, linux-cifs@vger.kernel.org, 
	samba-technical@lists.samba.org
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Note that kernels that backported this fix will also need this ksmbd
fix (fixes a bug when Macs mount to ksmbd)

commit 0268a7cc7fdc47d90b6c18859de7718d5059f6f1
Author: Namjae Jeon <linkinjeon@kernel.org>
Date:   Fri Apr 19 23:46:34 2024 +0900

    ksmbd: common: use struct_group_attr instead of struct_group for
network_open_info

    4byte padding cause the connection issue with the applications of MacOS=
.
    smb2_close response size increases by 4 bytes by padding, And the smb
    client of MacOS check it and stop the connection. This patch use
    struct_group_attr instead of struct_group for network_open_info to use
     __packed to avoid padding.

    Fixes: 0015eb6e1238 ("smb: client, common: fix fortify warnings")
    Cc: stable@vger.kernel.org
    Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
    Signed-off-by: Steve French <stfrench@microsoft.com>

On Mon, Dec 4, 2023 at 2:36=E2=80=AFPM Sasha Levin <sashal@kernel.org> wrot=
e:
>
> From: Dmitry Antipov <dmantipov@yandex.ru>
>
> [ Upstream commit 0015eb6e12384ff1c589928e84deac2ad1ceb236 ]
>
> When compiling with gcc version 14.0.0 20231126 (experimental)
> and CONFIG_FORTIFY_SOURCE=3Dy, I've noticed the following:
>
> In file included from ./include/linux/string.h:295,
>                  from ./include/linux/bitmap.h:12,
>                  from ./include/linux/cpumask.h:12,
>                  from ./arch/x86/include/asm/paravirt.h:17,
>                  from ./arch/x86/include/asm/cpuid.h:62,
>                  from ./arch/x86/include/asm/processor.h:19,
>                  from ./arch/x86/include/asm/cpufeature.h:5,
>                  from ./arch/x86/include/asm/thread_info.h:53,
>                  from ./include/linux/thread_info.h:60,
>                  from ./arch/x86/include/asm/preempt.h:9,
>                  from ./include/linux/preempt.h:79,
>                  from ./include/linux/spinlock.h:56,
>                  from ./include/linux/wait.h:9,
>                  from ./include/linux/wait_bit.h:8,
>                  from ./include/linux/fs.h:6,
>                  from fs/smb/client/smb2pdu.c:18:
> In function 'fortify_memcpy_chk',
>     inlined from '__SMB2_close' at fs/smb/client/smb2pdu.c:3480:4:
> ./include/linux/fortify-string.h:588:25: warning: call to '__read_overflo=
w2_field'
> declared with attribute warning: detected read beyond size of field (2nd =
parameter);
> maybe use struct_group()? [-Wattribute-warning]
>   588 |                         __read_overflow2_field(q_size_field, size=
);
>       |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~=
~
>
> and:
>
> In file included from ./include/linux/string.h:295,
>                  from ./include/linux/bitmap.h:12,
>                  from ./include/linux/cpumask.h:12,
>                  from ./arch/x86/include/asm/paravirt.h:17,
>                  from ./arch/x86/include/asm/cpuid.h:62,
>                  from ./arch/x86/include/asm/processor.h:19,
>                  from ./arch/x86/include/asm/cpufeature.h:5,
>                  from ./arch/x86/include/asm/thread_info.h:53,
>                  from ./include/linux/thread_info.h:60,
>                  from ./arch/x86/include/asm/preempt.h:9,
>                  from ./include/linux/preempt.h:79,
>                  from ./include/linux/spinlock.h:56,
>                  from ./include/linux/wait.h:9,
>                  from ./include/linux/wait_bit.h:8,
>                  from ./include/linux/fs.h:6,
>                  from fs/smb/client/cifssmb.c:17:
> In function 'fortify_memcpy_chk',
>     inlined from 'CIFS_open' at fs/smb/client/cifssmb.c:1248:3:
> ./include/linux/fortify-string.h:588:25: warning: call to '__read_overflo=
w2_field'
> declared with attribute warning: detected read beyond size of field (2nd =
parameter);
> maybe use struct_group()? [-Wattribute-warning]
>   588 |                         __read_overflow2_field(q_size_field, size=
);
>       |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~=
~
>
> In both cases, the fortification logic inteprets calls to 'memcpy()' as a=
n
> attempts to copy an amount of data which exceeds the size of the specifie=
d
> field (i.e. more than 8 bytes from __le64 value) and thus issues an overr=
ead
> warning. Both of these warnings may be silenced by using the convenient
> 'struct_group()' quirk.
>
> Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
> Acked-by: Namjae Jeon <linkinjeon@kernel.org>
> Signed-off-by: Steve French <stfrench@microsoft.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  fs/smb/client/cifspdu.h | 24 ++++++++++++++----------
>  fs/smb/client/cifssmb.c |  6 ++++--
>  fs/smb/client/smb2pdu.c |  8 +++-----
>  fs/smb/client/smb2pdu.h | 16 +++++++++-------
>  fs/smb/common/smb2pdu.h | 17 ++++++++++-------
>  5 files changed, 40 insertions(+), 31 deletions(-)
>
> diff --git a/fs/smb/client/cifspdu.h b/fs/smb/client/cifspdu.h
> index c403816d0b6c1..97bb1838555b4 100644
> --- a/fs/smb/client/cifspdu.h
> +++ b/fs/smb/client/cifspdu.h
> @@ -882,11 +882,13 @@ typedef struct smb_com_open_rsp {
>         __u8 OplockLevel;
>         __u16 Fid;
>         __le32 CreateAction;
> -       __le64 CreationTime;
> -       __le64 LastAccessTime;
> -       __le64 LastWriteTime;
> -       __le64 ChangeTime;
> -       __le32 FileAttributes;
> +       struct_group(common_attributes,
> +               __le64 CreationTime;
> +               __le64 LastAccessTime;
> +               __le64 LastWriteTime;
> +               __le64 ChangeTime;
> +               __le32 FileAttributes;
> +       );
>         __le64 AllocationSize;
>         __le64 EndOfFile;
>         __le16 FileType;
> @@ -2268,11 +2270,13 @@ typedef struct {
>  /* QueryFileInfo/QueryPathinfo (also for SetPath/SetFile) data buffer fo=
rmats */
>  /***********************************************************************=
*******/
>  typedef struct { /* data block encoding of response to level 263 QPathIn=
fo */
> -       __le64 CreationTime;
> -       __le64 LastAccessTime;
> -       __le64 LastWriteTime;
> -       __le64 ChangeTime;
> -       __le32 Attributes;
> +       struct_group(common_attributes,
> +               __le64 CreationTime;
> +               __le64 LastAccessTime;
> +               __le64 LastWriteTime;
> +               __le64 ChangeTime;
> +               __le32 Attributes;
> +       );
>         __u32 Pad1;
>         __le64 AllocationSize;
>         __le64 EndOfFile;       /* size ie offset to first free byte in f=
ile */
> diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
> index c90d4ec9292ca..67c5fc2b2db94 100644
> --- a/fs/smb/client/cifssmb.c
> +++ b/fs/smb/client/cifssmb.c
> @@ -1234,8 +1234,10 @@ CIFS_open(const unsigned int xid, struct cifs_open=
_parms *oparms, int *oplock,
>                 *oplock |=3D CIFS_CREATE_ACTION;
>
>         if (buf) {
> -               /* copy from CreationTime to Attributes */
> -               memcpy((char *)buf, (char *)&rsp->CreationTime, 36);
> +               /* copy commonly used attributes */
> +               memcpy(&buf->common_attributes,
> +                      &rsp->common_attributes,
> +                      sizeof(buf->common_attributes));
>                 /* the file_info buf is endian converted by caller */
>                 buf->AllocationSize =3D rsp->AllocationSize;
>                 buf->EndOfFile =3D rsp->EndOfFile;
> diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
> index 847d69d327c2a..aea7770fb5631 100644
> --- a/fs/smb/client/smb2pdu.c
> +++ b/fs/smb/client/smb2pdu.c
> @@ -3425,12 +3425,10 @@ __SMB2_close(const unsigned int xid, struct cifs_=
tcon *tcon,
>         } else {
>                 trace_smb3_close_done(xid, persistent_fid, tcon->tid,
>                                       ses->Suid);
> -               /*
> -                * Note that have to subtract 4 since struct network_open=
_info
> -                * has a final 4 byte pad that close response does not ha=
ve
> -                */
>                 if (pbuf)
> -                       memcpy(pbuf, (char *)&rsp->CreationTime, sizeof(*=
pbuf) - 4);
> +                       memcpy(&pbuf->network_open_info,
> +                              &rsp->network_open_info,
> +                              sizeof(pbuf->network_open_info));
>         }
>
>         atomic_dec(&tcon->num_remote_opens);
> diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h
> index 1237bb86e93a8..8ac99563487c1 100644
> --- a/fs/smb/client/smb2pdu.h
> +++ b/fs/smb/client/smb2pdu.h
> @@ -339,13 +339,15 @@ struct smb2_file_reparse_point_info {
>  } __packed;
>
>  struct smb2_file_network_open_info {
> -       __le64 CreationTime;
> -       __le64 LastAccessTime;
> -       __le64 LastWriteTime;
> -       __le64 ChangeTime;
> -       __le64 AllocationSize;
> -       __le64 EndOfFile;
> -       __le32 Attributes;
> +       struct_group(network_open_info,
> +               __le64 CreationTime;
> +               __le64 LastAccessTime;
> +               __le64 LastWriteTime;
> +               __le64 ChangeTime;
> +               __le64 AllocationSize;
> +               __le64 EndOfFile;
> +               __le32 Attributes;
> +       );
>         __le32 Reserved;
>  } __packed; /* level 34 Query also similar returned in close rsp and ope=
n rsp */
>
> diff --git a/fs/smb/common/smb2pdu.h b/fs/smb/common/smb2pdu.h
> index 9619015d78f29..778c1e3b70bc1 100644
> --- a/fs/smb/common/smb2pdu.h
> +++ b/fs/smb/common/smb2pdu.h
> @@ -699,13 +699,16 @@ struct smb2_close_rsp {
>         __le16 StructureSize; /* 60 */
>         __le16 Flags;
>         __le32 Reserved;
> -       __le64 CreationTime;
> -       __le64 LastAccessTime;
> -       __le64 LastWriteTime;
> -       __le64 ChangeTime;
> -       __le64 AllocationSize;  /* Beginning of FILE_STANDARD_INFO equiva=
lent */
> -       __le64 EndOfFile;
> -       __le32 Attributes;
> +       struct_group(network_open_info,
> +               __le64 CreationTime;
> +               __le64 LastAccessTime;
> +               __le64 LastWriteTime;
> +               __le64 ChangeTime;
> +               /* Beginning of FILE_STANDARD_INFO equivalent */
> +               __le64 AllocationSize;
> +               __le64 EndOfFile;
> +               __le32 Attributes;
> +       );
>  } __packed;
>
>
> --
> 2.42.0
>
>


--=20
Thanks,

Steve