[PATCH AUTOSEL 6.1 08/15] smb: Work around Clang __bdos() type confusion

[PATCH AUTOSEL 6.1 08/15] smb: Work around Clang __bdos() type confusion

[Sasha Levin]

From: Kees Cook <keescook@chromium.org>

[ Upstream commit 8deb05c84b63b4fdb8549e08942867a68924a5b8 ]

Recent versions of Clang gets confused about the possible size of the
"user" allocation, and CONFIG_FORTIFY_SOURCE ends up emitting a
warning[1]:

repro.c:126:4: warning: call to '__write_overflow_field' declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
  126 |                         __write_overflow_field(p_size_field, size);
      |                         ^

for this memset():

        int len;
        __le16 *user;
	...
        len = ses->user_name ? strlen(ses->user_name) : 0;
        user = kmalloc(2 + (len * 2), GFP_KERNEL);
	...
	if (len) {
		...
	} else {
		memset(user, '\0', 2);
	}

While Clang works on this bug[2], switch to using a direct assignment,
which avoids memset() entirely which both simplifies the code and silences
the false positive warning. (Making "len" size_t also silences the
warning, but the direct assignment seems better.)

Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://github.com/ClangBuiltLinux/linux/issues/1966 [1]
Link: https://github.com/llvm/llvm-project/issues/77813 [2]
Cc: Steve French <sfrench@samba.org>
Cc: Paulo Alcantara <pc@manguebit.com>
Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Shyam Prasad N <sprasad@microsoft.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: llvm@lists.linux.dev
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/cifsencrypt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/smb/client/cifsencrypt.c b/fs/smb/client/cifsencrypt.c
index d0ac2648c0d6..d3d4cf6321fd 100644
--- a/fs/smb/client/cifsencrypt.c
+++ b/fs/smb/client/cifsencrypt.c
@@ -444,7 +444,7 @@ static int calc_ntlmv2_hash(struct cifs_ses *ses, char *ntlmv2_hash,
 		len = cifs_strtoUTF16(user, ses->user_name, len, nls_cp);
 		UniStrupr(user);
 	} else {
-		memset(user, '\0', 2);
+		*(u16 *)user = 0;
 	}
 
 	rc = crypto_shash_update(ses->server->secmech.hmacmd5,
-- 
2.43.0

[PATCH AUTOSEL 6.1 09/15] cifs: translate network errors on send to -ECONNABORTED

[Sasha Levin]

From: Shyam Prasad N <sprasad@microsoft.com>

[ Upstream commit a68106a6928e0a6680f12bcc7338c0dddcfe4d11 ]

When the network stack returns various errors, we today bubble
up the error to the user (in case of soft mounts).

This change translates all network errors except -EINTR and
-EAGAIN to -ECONNABORTED. A similar approach is taken when
we receive network errors when reading from the socket.

The change also forces the cifsd thread to reconnect during
it's next activity.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/smb/client/transport.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c
index 8a1dd8407a3a..97bf46de8e42 100644
--- a/fs/smb/client/transport.c
+++ b/fs/smb/client/transport.c
@@ -427,10 +427,17 @@ __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 						  server->conn_id, server->hostname);
 	}
 smbd_done:
-	if (rc < 0 && rc != -EINTR)
+	/*
+	 * there's hardly any use for the layers above to know the
+	 * actual error code here. All they should do at this point is
+	 * to retry the connection and hope it goes away.
+	 */
+	if (rc < 0 && rc != -EINTR && rc != -EAGAIN) {
 		cifs_server_dbg(VFS, "Error %d sending data on socket to server\n",
 			 rc);
-	else if (rc > 0)
+		rc = -ECONNABORTED;
+		cifs_signal_cifsd_for_reconnect(server, false);
+	} else if (rc > 0)
 		rc = 0;
 out:
 	cifs_in_send_dec(server);
-- 
2.43.0