[PATCH AUTOSEL 6.6 29/32] smb: client, common: fix fortify warnings

Sasha Levin
2023-12-04T20:36:52Z

From: Dmitry Antipov <dmantipov@yandex.ru>

[ Upstream commit 0015eb6e12384ff1c589928e84deac2ad1ceb236 ]

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>
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 a75220db5c1e1..11081492d9436 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;
@@ -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 */
diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c
index 25503f1a4fd21..09e66ceb38a25 100644
--- a/fs/smb/client/cifssmb.c
+++ b/fs/smb/client/cifssmb.c
@@ -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;
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index c75a80bb6d9ee..3e388c6cb5c25 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -3377,12 +3377,10 @@ __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);
diff --git a/fs/smb/client/smb2pdu.h b/fs/smb/client/smb2pdu.h
index 220994d0a0f7f..db08194484e06 100644
--- a/fs/smb/client/smb2pdu.h
+++ b/fs/smb/client/smb2pdu.h
@@ -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 */

diff --git a/fs/smb/common/smb2pdu.h b/fs/smb/common/smb2pdu.h
index 319fb9ffc6a03..7d676e7fa5b1a 100644
--- a/fs/smb/common/smb2pdu.h
+++ b/fs/smb/common/smb2pdu.h
@@ -700,13 +700,16 @@ 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;

--
2.42.0