1 files changed, 132 insertions, 66 deletions

diff --git a/drivers/firewire/core-device.c b/drivers/firewire/core-device.c
index 9d0dfcbe2c1c..014cabd3afda 100644
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -18,6 +18,7 @@
  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
+#include <linux/bug.h>
 #include <linux/ctype.h>
 #include <linux/delay.h>
 #include <linux/device.h>
@@ -43,7 +44,7 @@
 
 #include "core.h"
 
-void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
+void fw_csr_iterator_init(struct fw_csr_iterator *ci, const u32 *p)
 {
 	ci->p = p + 1;
 	ci->end = ci->p + (p[0] >> 16);
@@ -59,9 +60,76 @@ int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
 }
 EXPORT_SYMBOL(fw_csr_iterator_next);
 
+static const u32 *search_leaf(const u32 *directory, int search_key)
+{
+	struct fw_csr_iterator ci;
+	int last_key = 0, key, value;
+
+	fw_csr_iterator_init(&ci, directory);
+	while (fw_csr_iterator_next(&ci, &key, &value)) {
+		if (last_key == search_key &&
+		    key == (CSR_DESCRIPTOR | CSR_LEAF))
+			return ci.p - 1 + value;
+
+		last_key = key;
+	}
+
+	return NULL;
+}
+
+static int textual_leaf_to_string(const u32 *block, char *buf, size_t size)
+{
+	unsigned int quadlets, i;
+	char c;
+
+	if (!size || !buf)
+		return -EINVAL;
+
+	quadlets = min(block[0] >> 16, 256U);
+	if (quadlets < 2)
+		return -ENODATA;
+
+	if (block[1] != 0 || block[2] != 0)
+		/* unknown language/character set */
+		return -ENODATA;
+
+	block += 3;
+	quadlets -= 2;
+	for (i = 0; i < quadlets * 4 && i < size - 1; i++) {
+		c = block[i / 4] >> (24 - 8 * (i % 4));
+		if (c == '\0')
+			break;
+		buf[i] = c;
+	}
+	buf[i] = '\0';
+
+	return i;
+}
+
+/**
+ * fw_csr_string - reads a string from the configuration ROM
+ * @directory: e.g. root directory or unit directory
+ * @key: the key of the preceding directory entry
+ * @buf: where to put the string
+ * @size: size of @buf, in bytes
+ *
+ * The string is taken from a minimal ASCII text descriptor leaf after
+ * the immediate entry with @key.  The string is zero-terminated.
+ * Returns strlen(buf) or a negative error code.
+ */
+int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
+{
+	const u32 *leaf = search_leaf(directory, key);
+	if (!leaf)
+		return -ENOENT;
+
+	return textual_leaf_to_string(leaf, buf, size);
+}
+EXPORT_SYMBOL(fw_csr_string);
+
 static bool is_fw_unit(struct device *dev);
 
-static int match_unit_directory(u32 *directory, u32 match_flags,
+static int match_unit_directory(const u32 *directory, u32 match_flags,
 				const struct ieee1394_device_id *id)
 {
 	struct fw_csr_iterator ci;
@@ -195,7 +263,7 @@ static ssize_t show_immediate(struct device *dev,
 	struct config_rom_attribute *attr =
 		container_of(dattr, struct config_rom_attribute, attr);
 	struct fw_csr_iterator ci;
-	u32 *dir;
+	const u32 *dir;
 	int key, value, ret = -ENOENT;
 
 	down_read(&fw_device_rwsem);
@@ -226,10 +294,10 @@ static ssize_t show_text_leaf(struct device *dev,
 {
 	struct config_rom_attribute *attr =
 		container_of(dattr, struct config_rom_attribute, attr);
-	struct fw_csr_iterator ci;
-	u32 *dir, *block = NULL, *p, *end;
-	int length, key, value, last_key = 0, ret = -ENOENT;
-	char *b;
+	const u32 *dir;
+	size_t bufsize;
+	char dummy_buf[2];
+	int ret;
 
 	down_read(&fw_device_rwsem);
 
@@ -238,40 +306,23 @@ static ssize_t show_text_leaf(struct device *dev,
 	else
 		dir = fw_device(dev)->config_rom + 5;
 
-	fw_csr_iterator_init(&ci, dir);
-	while (fw_csr_iterator_next(&ci, &key, &value)) {
-		if (attr->key == last_key &&
-		    key == (CSR_DESCRIPTOR | CSR_LEAF))
-			block = ci.p - 1 + value;
-		last_key = key;
+	if (buf) {
+		bufsize = PAGE_SIZE - 1;
+	} else {
+		buf = dummy_buf;
+		bufsize = 1;
 	}
 
-	if (block == NULL)
-		goto out;
-
-	length = min(block[0] >> 16, 256U);
-	if (length < 3)
-		goto out;
-
-	if (block[1] != 0 || block[2] != 0)
-		/* Unknown encoding. */
-		goto out;
+	ret = fw_csr_string(dir, attr->key, buf, bufsize);
 
-	if (buf == NULL) {
-		ret = length * 4;
-		goto out;
+	if (ret >= 0) {
+		/* Strip trailing whitespace and add newline. */
+		while (ret > 0 && isspace(buf[ret - 1]))
+			ret--;
+		strcpy(buf + ret, "\n");
+		ret++;
 	}
 
-	b = buf;
-	end = &block[length + 1];
-	for (p = &block[3]; p < end; p++, b += 4)
-		* (u32 *) b = (__force u32) __cpu_to_be32(*p);
-
-	/* Strip trailing whitespace and add newline. */
-	while (b--, (isspace(*b) || *b == '\0') && b > buf);
-	strcpy(b + 1, "\n");
-	ret = b + 2 - buf;
- out:
 	up_read(&fw_device_rwsem);
 
 	return ret;
@@ -371,7 +422,7 @@ static ssize_t guid_show(struct device *dev,
 	return ret;
 }
 
-static int units_sprintf(char *buf, u32 *directory)
+static int units_sprintf(char *buf, const u32 *directory)
 {
 	struct fw_csr_iterator ci;
 	int key, value;
@@ -441,28 +492,29 @@ static int read_rom(struct fw_device *device,
 	return rcode;
 }
 
-#define READ_BIB_ROM_SIZE	256
-#define READ_BIB_STACK_SIZE	16
+#define MAX_CONFIG_ROM_SIZE 256
 
 /*
  * Read the bus info block, perform a speed probe, and read all of the rest of
  * the config ROM.  We do all this with a cached bus generation.  If the bus
- * generation changes under us, read_bus_info_block will fail and get retried.
+ * generation changes under us, read_config_rom will fail and get retried.
  * It's better to start all over in this case because the node from which we
  * are reading the ROM may have changed the ROM during the reset.
  */
-static int read_bus_info_block(struct fw_device *device, int generation)
+static int read_config_rom(struct fw_device *device, int generation)
 {
-	u32 *rom, *stack, *old_rom, *new_rom;
+	const u32 *old_rom, *new_rom;
+	u32 *rom, *stack;
 	u32 sp, key;
 	int i, end, length, ret = -1;
 
-	rom = kmalloc(sizeof(*rom) * READ_BIB_ROM_SIZE +
-		      sizeof(*stack) * READ_BIB_STACK_SIZE, GFP_KERNEL);
+	rom = kmalloc(sizeof(*rom) * MAX_CONFIG_ROM_SIZE +
+		      sizeof(*stack) * MAX_CONFIG_ROM_SIZE, GFP_KERNEL);
 	if (rom == NULL)
 		return -ENOMEM;
 
-	stack = &rom[READ_BIB_ROM_SIZE];
+	stack = &rom[MAX_CONFIG_ROM_SIZE];
+	memset(rom, 0, sizeof(*rom) * MAX_CONFIG_ROM_SIZE);
 
 	device->max_speed = SCODE_100;
 
@@ -529,40 +581,54 @@ static int read_bus_info_block(struct fw_device *device, int generation)
 		 */
 		key = stack[--sp];
 		i = key & 0xffffff;
-		if (i >= READ_BIB_ROM_SIZE)
-			/*
-			 * The reference points outside the standard
-			 * config rom area, something's fishy.
-			 */
+		if (WARN_ON(i >= MAX_CONFIG_ROM_SIZE))
 			goto out;
 
 		/* Read header quadlet for the block to get the length. */
 		if (read_rom(device, generation, i, &rom[i]) != RCODE_COMPLETE)
 			goto out;
 		end = i + (rom[i] >> 16) + 1;
-		i++;
-		if (end > READ_BIB_ROM_SIZE)
+		if (end > MAX_CONFIG_ROM_SIZE) {
 			/*
-			 * This block extends outside standard config
-			 * area (and the array we're reading it
-			 * into).  That's broken, so ignore this
-			 * device.
+			 * This block extends outside the config ROM which is
+			 * a firmware bug.  Ignore this whole block, i.e.
+			 * simply set a fake block length of 0.
 			 */
-			goto out;
+			fw_error("skipped invalid ROM block %x at %llx\n",
+				 rom[i],
+				 i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
+			rom[i] = 0;
+			end = i;
+		}
+		i++;
 
 		/*
 		 * Now read in the block.  If this is a directory
 		 * block, check the entries as we read them to see if
 		 * it references another block, and push it in that case.
 		 */
-		while (i < end) {
+		for (; i < end; i++) {
 			if (read_rom(device, generation, i, &rom[i]) !=
 			    RCODE_COMPLETE)
 				goto out;
-			if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
-			    sp < READ_BIB_STACK_SIZE)
-				stack[sp++] = i + rom[i];
-			i++;
+
+			if ((key >> 30) != 3 || (rom[i] >> 30) < 2)
+				continue;
+			/*
+			 * Offset points outside the ROM.  May be a firmware
+			 * bug or an Extended ROM entry (IEEE 1212-2001 clause
+			 * 7.7.18).  Simply overwrite this pointer here by a
+			 * fake immediate entry so that later iterators over
+			 * the ROM don't have to check offsets all the time.
+			 */
+			if (i + (rom[i] & 0xffffff) >= MAX_CONFIG_ROM_SIZE) {
+				fw_error("skipped unsupported ROM entry %x at %llx\n",
+					 rom[i],
+					 i * 4 | CSR_REGISTER_BASE | CSR_CONFIG_ROM);
+				rom[i] = 0;
+				continue;
+			}
+			stack[sp++] = i + rom[i];
 		}
 		if (length < i)
 			length = i;
@@ -905,7 +971,7 @@ static void fw_device_init(struct work_struct *work)
 	 * device.
 	 */
 
-	if (read_bus_info_block(device, device->generation) < 0) {
+	if (read_config_rom(device, device->generation) < 0) {
 		if (device->config_rom_retries < MAX_RETRIES &&
 		    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 			device->config_rom_retries++;
@@ -1022,7 +1088,7 @@ enum {
 };
 
 /* Reread and compare bus info block and header of root directory */
-static int reread_bus_info_block(struct fw_device *device, int generation)
+static int reread_config_rom(struct fw_device *device, int generation)
 {
 	u32 q;
 	int i;
@@ -1048,7 +1114,7 @@ static void fw_device_refresh(struct work_struct *work)
 	struct fw_card *card = device->card;
 	int node_id = device->node_id;
 
-	switch (reread_bus_info_block(device, device->generation)) {
+	switch (reread_config_rom(device, device->generation)) {
 	case REREAD_BIB_ERROR:
 		if (device->config_rom_retries < MAX_RETRIES / 2 &&
 		    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
@@ -1082,7 +1148,7 @@ static void fw_device_refresh(struct work_struct *work)
 	 */
 	device_for_each_child(&device->device, NULL, shutdown_unit);
 
-	if (read_bus_info_block(device, device->generation) < 0) {
+	if (read_config_rom(device, device->generation) < 0) {
 		if (device->config_rom_retries < MAX_RETRIES &&
 		    atomic_read(&device->state) == FW_DEVICE_INITIALIZING) {
 			device->config_rom_retries++;