From: Takashi Iwai <tiwai@suse.de>
Date: Sun, 15 Mar 2020 09:42:39 +0000 (+0100)
Subject: scsi: megaraid_sas: Use scnprintf() for avoiding potential buffer overflow
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=ff33d0e2b9d10ba8a0ccb09261f5f9adb1ab32cb;p=linux.git

scsi: megaraid_sas: Use scnprintf() for avoiding potential buffer overflow

Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().

Also corrected the wrongly passed limit size.  The remaining buffer size
must be decremented.

Link: https://lore.kernel.org/r/20200315094241.9086-7-tiwai@suse.de
Cc: "James E . J . Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K . Petersen" <martin.petersen@oracle.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumit Saxena <sumit.saxena@broadcom.com>
Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
---

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 5bebdd397580c..babe85d7b537a 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -2987,9 +2987,10 @@ megasas_dump_sys_regs(void __iomem *reg_set, char *buf)
 	u32 __iomem *reg = (u32 __iomem *)reg_set;
 
 	for (i = 0; i < sz / sizeof(u32); i++) {
-		bytes_wrote += snprintf(loc + bytes_wrote, PAGE_SIZE,
-					"%08x: %08x\n", (i * 4),
-					readl(&reg[i]));
+		bytes_wrote += scnprintf(loc + bytes_wrote,
+					 PAGE_SIZE - bytes_wrote,
+					 "%08x: %08x\n", (i * 4),
+					 readl(&reg[i]));
 	}
 	return bytes_wrote;
 }