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smb: client, common: fix fortify warnings
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When compiling with gcc version 14.0.0 20231126 (experimental)
and CONFIG_FORTIFY_SOURCE=y, 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_overflow2_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_overflow2_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 an
attempts to copy an amount of data which exceeds the size of the specified
field (i.e. more than 8 bytes from __le64 value) and thus issues an overread
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>
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@dmantipov
dmantipov authored and Steve French committed Nov 30, 2023
1 parent 8801015 commit 0015eb6
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Showing 5 changed files with 40 additions and 31 deletions.
24 changes: 14 additions & 10 deletions fs/smb/client/cifspdu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -2264,11 +2266,13 @@ typedef struct {
/* QueryFileInfo/QueryPathinfo (also for SetPath/SetFile) data buffer formats */
/******************************************************************************/
typedef struct { /* data block encoding of response to level 263 QPathInfo */
__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 file */
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6 changes: 4 additions & 2 deletions fs/smb/client/cifssmb.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1244,8 +1244,10 @@ CIFS_open(const unsigned int xid, struct cifs_open_parms *oparms, int *oplock,
*oplock |= 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 = rsp->AllocationSize;
buf->EndOfFile = rsp->EndOfFile;
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8 changes: 3 additions & 5 deletions fs/smb/client/smb2pdu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3472,12 +3472,10 @@ __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 have
*/
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);
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16 changes: 9 additions & 7 deletions fs/smb/client/smb2pdu.h
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Original file line number Diff line number Diff line change
Expand Up @@ -319,13 +319,15 @@ 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 open rsp */

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17 changes: 10 additions & 7 deletions fs/smb/common/smb2pdu.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -702,13 +702,16 @@ 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 equivalent */
__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;


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