mmc: core: use sysfs_emit() instead of sprintf()

sprintf() (still used in the MMC core for the sysfs output) is vulnerable
to the buffer overflow. Use the new-fangled sysfs_emit() instead.

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/core/bus.c

···
 #include <linux/stat.h>
 #include <linux/of.h>
 #include <linux/pm_runtime.h>
+#include <linux/sysfs.h>
 
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
···
 
 	switch (card->type) {
 	case MMC_TYPE_MMC:
-		return sprintf(buf, "MMC\n");
+		return sysfs_emit(buf, "MMC\n");
 	case MMC_TYPE_SD:
-		return sprintf(buf, "SD\n");
+		return sysfs_emit(buf, "SD\n");
 	case MMC_TYPE_SDIO:
-		return sprintf(buf, "SDIO\n");
+		return sysfs_emit(buf, "SDIO\n");
 	case MMC_TYPE_SD_COMBO:
-		return sprintf(buf, "SDcombo\n");
+		return sysfs_emit(buf, "SDcombo\n");
 	default:
 		return -EFAULT;
 	}

drivers/mmc/core/bus.h

···
 #define _MMC_CORE_BUS_H
 
 #include <linux/device.h>
+#include <linux/sysfs.h>
 
 struct mmc_host;
 struct mmc_card;
···
 static ssize_t mmc_##name##_show (struct device *dev, struct device_attribute *attr, char *buf)	\
 {										\
 	struct mmc_card *card = mmc_dev_to_card(dev);				\
-	return sprintf(buf, fmt, args);						\
+	return sysfs_emit(buf, fmt, args);					\
 }										\
 static DEVICE_ATTR(name, S_IRUGO, mmc_##name##_show, NULL)
 

drivers/mmc/core/mmc.c

···
 #include <linux/slab.h>
 #include <linux/stat.h>
 #include <linux/pm_runtime.h>
+#include <linux/sysfs.h>
 
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
···
 {
 	struct mmc_card *card = mmc_dev_to_card(dev);
 
-	if (card->ext_csd.rev < 7) {
-		return sprintf(buf, "0x%x\n", card->cid.fwrev);
-	} else {
-		return sprintf(buf, "0x%*phN\n", MMC_FIRMWARE_LEN,
-			       card->ext_csd.fwrev);
-	}
+	if (card->ext_csd.rev < 7)
+		return sysfs_emit(buf, "0x%x\n", card->cid.fwrev);
+	else
+		return sysfs_emit(buf, "0x%*phN\n", MMC_FIRMWARE_LEN,
+				  card->ext_csd.fwrev);
 }
 
 static DEVICE_ATTR(fwrev, S_IRUGO, mmc_fwrev_show, NULL);
···
 	struct mmc_host *host = card->host;
 
 	if (card->csd.dsr_imp && host->dsr_req)
-		return sprintf(buf, "0x%x\n", host->dsr);
+		return sysfs_emit(buf, "0x%x\n", host->dsr);
 	else
 		/* return default DSR value */
-		return sprintf(buf, "0x%x\n", 0x404);
+		return sysfs_emit(buf, "0x%x\n", 0x404);
 }
 
 static DEVICE_ATTR(dsr, S_IRUGO, mmc_dsr_show, NULL);

drivers/mmc/core/sd.c

···
 #include <linux/stat.h>
 #include <linux/pm_runtime.h>
 #include <linux/scatterlist.h>
+#include <linux/sysfs.h>
 
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
···
 MMC_DEV_ATTR(rca, "0x%04x\n", card->rca);
 
 
-static ssize_t mmc_dsr_show(struct device *dev,
-                           struct device_attribute *attr,
-                           char *buf)
+static ssize_t mmc_dsr_show(struct device *dev, struct device_attribute *attr,
+			    char *buf)
 {
-       struct mmc_card *card = mmc_dev_to_card(dev);
-       struct mmc_host *host = card->host;
+	struct mmc_card *card = mmc_dev_to_card(dev);
+	struct mmc_host *host = card->host;
 
-       if (card->csd.dsr_imp && host->dsr_req)
-               return sprintf(buf, "0x%x\n", host->dsr);
-       else
-               /* return default DSR value */
-               return sprintf(buf, "0x%x\n", 0x404);
+	if (card->csd.dsr_imp && host->dsr_req)
+		return sysfs_emit(buf, "0x%x\n", host->dsr);
+	/* return default DSR value */
+	return sysfs_emit(buf, "0x%x\n", 0x404);
 }
 
 static DEVICE_ATTR(dsr, S_IRUGO, mmc_dsr_show, NULL);
···
 												\
 	if (num > card->num_info)								\
 		return -ENODATA;								\
-	if (!card->info[num-1][0])								\
+	if (!card->info[num - 1][0])								\
 		return 0;									\
-	return sprintf(buf, "%s\n", card->info[num-1]);						\
+	return sysfs_emit(buf, "%s\n", card->info[num - 1]);					\
 }												\
 static DEVICE_ATTR_RO(info##num)
 

drivers/mmc/core/sdio.c

···
 
 #include <linux/err.h>
 #include <linux/pm_runtime.h>
+#include <linux/sysfs.h>
 
 #include <linux/mmc/host.h>
 #include <linux/mmc/card.h>
···
 												\
 	if (num > card->num_info)								\
 		return -ENODATA;								\
-	if (!card->info[num-1][0])								\
+	if (!card->info[num - 1][0])								\
 		return 0;									\
-	return sprintf(buf, "%s\n", card->info[num-1]);						\
+	return sysfs_emit(buf, "%s\n", card->info[num - 1]);					\
 }												\
 static DEVICE_ATTR_RO(info##num)
 

drivers/mmc/core/sdio_bus.c

···
 #include <linux/pm_runtime.h>
 #include <linux/pm_domain.h>
 #include <linux/acpi.h>
+#include <linux/sysfs.h>
 
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
···
 	struct sdio_func *func;						\
 									\
 	func = dev_to_sdio_func (dev);					\
-	return sprintf(buf, format_string, args);			\
+	return sysfs_emit(buf, format_string, args);			\
 }									\
 static DEVICE_ATTR_RO(field)
 
···
 												\
 	if (num > func->num_info)								\
 		return -ENODATA;								\
-	if (!func->info[num-1][0])								\
+	if (!func->info[num - 1][0])								\
 		return 0;									\
-	return sprintf(buf, "%s\n", func->info[num-1]);						\
+	return sysfs_emit(buf, "%s\n", func->info[num - 1]);					\
 }												\
 static DEVICE_ATTR_RO(info##num)