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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Dmitry Antipov <dmantipov@yandex.ru>,
        Namjae Jeon <linkinjeon@kernel.org>,
        Steve French <stfrench@microsoft.com>,
        Sasha Levin <sashal@kernel.org>, sfrench@samba.org,
        linux-cifs@vger.kernel.org, samba-technical@lists.samba.org
Subject: [PATCH AUTOSEL 6.1 15/17] smb: client, common: fix fortify warnings
Date:   Mon,  4 Dec 2023 15:35:00 -0500
Message-ID: <20231204203514.2093855-15-sashal@kernel.org>
In-Reply-To: <20231204203514.2093855-1-sashal@kernel.org>
References: <20231204203514.2093855-1-sashal@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
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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 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 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 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 |= 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 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 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 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 open 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 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