[PATCH v3 net] ptp: clockmatrix: bug fix for idtcm_strverscmp

From: min.li.xe
Date: Tue Nov 24 2020 - 21:58:58 EST


From: Min Li <min.li.xe@xxxxxxxxxxx>

Feed kstrtou8 with NULL terminated string.

Changes since v1:
-Use sscanf to get rid of adhoc string parse.
Changes since v2:
-Check if sscanf returns 3.

Signed-off-by: Min Li <min.li.xe@xxxxxxxxxxx>
---
drivers/ptp/ptp_clockmatrix.c | 49 ++++++++++++++-----------------------------
1 file changed, 16 insertions(+), 33 deletions(-)

diff --git a/drivers/ptp/ptp_clockmatrix.c b/drivers/ptp/ptp_clockmatrix.c
index e020faf..6632557 100644
--- a/drivers/ptp/ptp_clockmatrix.c
+++ b/drivers/ptp/ptp_clockmatrix.c
@@ -103,43 +103,26 @@ static int timespec_to_char_array(struct timespec64 const *ts,
return 0;
}

-static int idtcm_strverscmp(const char *ver1, const char *ver2)
+static int idtcm_strverscmp(const char *version1, const char *version2)
{
- u8 num1;
- u8 num2;
- int result = 0;
-
- /* loop through each level of the version string */
- while (result == 0) {
- /* extract leading version numbers */
- if (kstrtou8(ver1, 10, &num1) < 0)
- return -1;
+ u8 ver1[3], ver2[3];
+ int i;

- if (kstrtou8(ver2, 10, &num2) < 0)
- return -1;
+ if (sscanf(version1, "%hhu.%hhu.%hhu",
+ &ver1[0], &ver1[1], &ver1[2]) != 3)
+ return -1;
+ if (sscanf(version2, "%hhu.%hhu.%hhu",
+ &ver2[0], &ver2[1], &ver2[2]) != 3)
+ return -1;

- /* if numbers differ, then set the result */
- if (num1 < num2)
- result = -1;
- else if (num1 > num2)
- result = 1;
- else {
- /* if numbers are the same, go to next level */
- ver1 = strchr(ver1, '.');
- ver2 = strchr(ver2, '.');
- if (!ver1 && !ver2)
- break;
- else if (!ver1)
- result = -1;
- else if (!ver2)
- result = 1;
- else {
- ver1++;
- ver2++;
- }
- }
+ for (i = 0; i < 3; i++) {
+ if (ver1[i] > ver2[i])
+ return 1;
+ if (ver1[i] < ver2[i])
+ return -1;
}
- return result;
+
+ return 0;
}

static int idtcm_xfer_read(struct idtcm *idtcm,
--
2.7.4