ALSA: firewire-lib/bebob/oxfw: improve response evaluation for AV/C commands

In ALSA firewire stack, some AV/C commands are supported, including
vendor's extensions. Drivers includes response parser of each command,
according to its requirements, while the parser is written with loose
fashion in two points; error check and length check. This doesn't cause
any issues such as kernel corruption, but should be improved.

This commit modifies evaluations of return value on each parsers.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/bebob/bebob_command.c

@@ -31,13 +31,15 @@ int avc_audio_set_selector(struct fw_unit *unit, unsigned int subunit_id,
 	err = fcp_avc_transaction(unit, buf, 12, buf, 12,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(7) | BIT(8));
-	if (err > 0 && err < 9)
+	if (err < 0)
+		;
+	else if (err < 9)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
 	else if (buf[0] == 0x0a) /* REJECTED */
 		err = -EINVAL;
-	else if (err > 0)
+	else
 		err = 0;
 
 	kfree(buf);
@@ -67,7 +69,9 @@ int avc_audio_get_selector(struct fw_unit *unit, unsigned int subunit_id,
 	err = fcp_avc_transaction(unit, buf, 12, buf, 12,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(8));
-	if (err > 0 && err < 9)
+	if (err < 0)
+		;
+	else if (err < 9)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -120,7 +124,9 @@ int avc_bridgeco_get_plug_type(struct fw_unit *unit,
 	err = fcp_avc_transaction(unit, buf, 12, buf, 12,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(7) | BIT(9));
-	if ((err >= 0) && (err < 8))
+	if (err < 0)
+		;
+	else if (err < 11)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -150,7 +156,9 @@ int avc_bridgeco_get_plug_ch_pos(struct fw_unit *unit,
 	err = fcp_avc_transaction(unit, buf, 12, buf, 256,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) |
 				  BIT(5) | BIT(6) | BIT(7) | BIT(9));
-	if ((err >= 0) && (err < 8))
+	if (err < 0)
+		;
+	else if (err < 11)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -187,7 +195,9 @@ int avc_bridgeco_get_plug_section_type(struct fw_unit *unit,
 	err = fcp_avc_transaction(unit, buf, 12, buf, 12,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(7) | BIT(9) | BIT(10));
-	if ((err >= 0) && (err < 8))
+	if (err < 0)
+		;
+	else if (err < 12)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -221,7 +231,9 @@ int avc_bridgeco_get_plug_input(struct fw_unit *unit,
 	err = fcp_avc_transaction(unit, buf, 16, buf, 16,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(7));
-	if ((err >= 0) && (err < 8))
+	if (err < 0)
+		;
+	else if (err < 16)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -260,7 +272,9 @@ int avc_bridgeco_get_plug_strm_fmt(struct fw_unit *unit,
 	err = fcp_avc_transaction(unit, buf, 12, buf, *len,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(7) | BIT(10));
-	if ((err >= 0) && (err < 12))
+	if (err < 0)
+		;
+	else if (err < 12)
 		err = -EIO;
 	else if (buf[0] == 0x08)        /* NOT IMPLEMENTED */
 		err = -ENOSYS;

sound/firewire/fcp.c

@@ -63,7 +63,9 @@ int avc_general_set_sig_fmt(struct fw_unit *unit, unsigned int rate,
 	/* do transaction and check buf[1-5] are the same against command */
 	err = fcp_avc_transaction(unit, buf, 8, buf, 8,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5));
-	if (err >= 0 && err < 8)
+	if (err < 0)
+		;
+	else if (err < 8)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -106,7 +108,9 @@ int avc_general_get_sig_fmt(struct fw_unit *unit, unsigned int *rate,
 	/* do transaction and check buf[1-4] are the same against command */
 	err = fcp_avc_transaction(unit, buf, 8, buf, 8,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4));
-	if (err >= 0 && err < 8)
+	if (err < 0)
+		;
+	else if (err < 8)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -154,7 +158,9 @@ int avc_general_get_plug_info(struct fw_unit *unit, unsigned int subunit_type,
 	buf[3] = 0xff & subfunction;
 
 	err = fcp_avc_transaction(unit, buf, 8, buf, 8, BIT(1) | BIT(2));
-	if (err >= 0 && err < 8)
+	if (err < 0)
+		;
+	else if (err < 8)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;

sound/firewire/oxfw/oxfw-command.c

@@ -34,7 +34,9 @@ int avc_stream_set_format(struct fw_unit *unit, enum avc_general_plug_dir dir,
 	err = fcp_avc_transaction(unit, buf, len + 10, buf, len + 10,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(7) | BIT(8));
-	if ((err > 0) && (err < len + 10))
+	if (err < 0)
+		;
+	else if (err < len + 10)
 		err = -EIO;
 	else if (buf[0] == 0x08) /* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -77,7 +79,9 @@ int avc_stream_get_format(struct fw_unit *unit,
 	err = fcp_avc_transaction(unit, buf, 12, buf, *len,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5) |
 				  BIT(6) | BIT(7));
-	if ((err > 0) && (err < 10))
+	if (err < 0)
+		;
+	else if (err < 12)
 		err = -EIO;
 	else if (buf[0] == 0x08)	/* NOT IMPLEMENTED */
 		err = -ENOSYS;
@@ -139,7 +143,9 @@ int avc_general_inquiry_sig_fmt(struct fw_unit *unit, unsigned int rate,
 	/* do transaction and check buf[1-5] are the same against command */
 	err = fcp_avc_transaction(unit, buf, 8, buf, 8,
 				  BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(5));
-	if ((err > 0) && (err < 8))
+	if (err < 0)
+		;
+	else if (err < 8)
 		err = -EIO;
 	else if (buf[0] == 0x08)	/* NOT IMPLEMENTED */
 		err = -ENOSYS;