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From:   oracleks043021@gmail.com
To:     beanhuo@micron.com, kenny.gibbons@oracle.com,
        kimito.sakata@oracle.com, rkamdar@micron.com, chris@printf.net,
        ulf.hansson@linaro.org
Cc:     linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v1] mmc-utils: Fix for Firmware Version string printing
Date:   Mon, 12 Jul 2021 23:34:58 -0600
Message-Id: <20210713053458.1441-1-oracleks043021@gmail.com>
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From: Kimito Sakata <kimito.sakata@oracle.com>

Added a local buffer to create a NULL terminated string to print the
Firmware Version instead of attempting to print directly from
ext_csd buffer. The last byte of the Firmware Version field may not
be NULL and the next field may also not be which may cause it to
print garbage.

Tested on x86 platform.
---
 mmc_cmds.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mmc_cmds.c b/mmc_cmds.c
index afa85b7..205e6e5 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -1392,6 +1392,7 @@ int do_read_extcsd(int nargs, char **argv)
 	__u32 regl;
 	int fd, ret;
 	char *device;
+	char lbuf[10];
 	const char *str;
 
 	if (nargs != 2) {
@@ -1833,8 +1834,9 @@ int do_read_extcsd(int nargs, char **argv)
 	}
 
 	if (ext_csd_rev >= 7) {
-		printf("eMMC Firmware Version: %s\n",
-			(char*)&ext_csd[EXT_CSD_FIRMWARE_VERSION]);
+                memset(lbuf, 0, sizeof(lbuf));
+		strncpy(lbuf, (char*)&ext_csd[EXT_CSD_FIRMWARE_VERSION], 8);
+		printf("eMMC Firmware Version: %s\n", lbuf);
 		printf("eMMC Life Time Estimation A [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A]: 0x%02x\n",
 			ext_csd[EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A]);
 		printf("eMMC Life Time Estimation B [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_B]: 0x%02x\n",
-- 
2.31.1