From: Dan Albert <danalbert@google.com>
Date: Tue, 7 Oct 2014 18:07:53 +0000 (-0700)
Subject: Use snprintf instead of sprintf.
X-Git-Tag: android-x86-7.1-r1~757^2~584^2
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=b0fd55608e707b3e9b5c2937537414be7d098afd;p=android-x86%2Fbionic.git

Use snprintf instead of sprintf.

At -O0, the attribute warning on sprintf is actually triggered (why
doesn't this happen with -Os?!) and promoted to an error by -Werror.
asctime64_r() is a non-standard function, but the IBM docs state that
the buffer is assumed to be at least 26 characters wide, and the
format string does limit to that (assuming a 4 digit year, also
defined by the IBM docs).

http://www-01.ibm.com/support/knowledgecenter/SSLTBW_2.1.0/com.ibm.zos.v2r1.bpxbd00/asctimer.htm

Change-Id: I1c884474a769aa16c53e985c3d8d694c478c1189
---

diff --git a/libc/bionic/time64.c b/libc/bionic/time64.c
index 95dfab539..da38bf3b6 100644
--- a/libc/bionic/time64.c
+++ b/libc/bionic/time64.c
@@ -748,10 +748,24 @@ static int valid_tm_mon( const struct TM* date ) {
 char *asctime64_r( const struct TM* date, char *result ) {
     /* I figure everything else can be displayed, even hour 25, but if
        these are out of range we walk off the name arrays */
-    if( !valid_tm_wday(date) || !valid_tm_mon(date) )
+    if (!valid_tm_wday(date) || !valid_tm_mon(date)) {
         return NULL;
+    }
+
+    /* Docs state this function does not support years beyond 9999. */
+    if (1900 + date->tm_year > 9999) {
+        return NULL;
+    }
 
-    sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
+    /*
+     * The IBM docs for this function state that the result buffer can be
+     * assumed to be at least 26 bytes wide. The docs also state that this is
+     * only valid for years <= 9999, so we know this format string will not
+     * print more than that many characters.
+     *
+     * http://www-01.ibm.com/support/knowledgecenter/SSLTBW_2.1.0/com.ibm.zos.v2r1.bpxbd00/asctimer.htm
+     */
+    snprintf(result, 26, "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n",
         wday_name[date->tm_wday],
         mon_name[date->tm_mon],
         date->tm_mday, date->tm_hour,