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commit 3ab3c16db6a5674f53cf23d56512a405fde0b2c9
Author: Daniel Stenberg <daniel@haxx.se>
Date: Tue Nov 8 15:32:37 2016 +0100
printf: fix floating point buffer overflow issues
... and add a bunch of floating point printf tests
Upstream-Status: Backport
https://curl.haxx.se/CVE-2016-9586.patch
dropped the tests as they require more changes to work.
CVE: CVE-2016-9586
Signed-off-by: Thiruvadi Rajaraman <trajaraman@mvista.com>
Index: curl-7.50.1/lib/mprintf.c
===================================================================
--- curl-7.50.1.orig/lib/mprintf.c 2017-06-15 18:24:08.934720707 +0530
+++ curl-7.50.1/lib/mprintf.c 2017-06-15 18:24:09.318720721 +0530
@@ -92,7 +92,8 @@
# define mp_uintmax_t unsigned long
#endif
-#define BUFFSIZE 256 /* buffer for long-to-str and float-to-str calcs */
+#define BUFFSIZE 326 /* buffer for long-to-str and float-to-str calcs, should
+ fit negative DBL_MAX (317 letters) */
#define MAX_PARAMETERS 128 /* lame static limit */
#ifdef __AMIGA__
@@ -910,12 +911,25 @@
*fptr = 0;
if(width >= 0) {
+ if(width >= (long)sizeof(work))
+ width = sizeof(work)-1;
/* RECURSIVE USAGE */
len = curl_msnprintf(fptr, left, "%ld", width);
fptr += len;
left -= len;
}
if(prec >= 0) {
+ /* for each digit in the integer part, we can have one less
+ precision */
+ size_t maxprec = sizeof(work) - 2;
+ double val = p->data.dnum;
+ while(val >= 10.0) {
+ val /= 10;
+ maxprec--;
+ }
+
+ if(prec > (long)maxprec)
+ prec = maxprec-1;
/* RECURSIVE USAGE */
len = curl_msnprintf(fptr, left, ".%ld", prec);
fptr += len;
@@ -935,7 +949,9 @@
/* NOTE NOTE NOTE!! Not all sprintf implementations return number of
output characters */
(sprintf)(work, formatbuf, p->data.dnum);
-
+#ifdef CURLDEBUG
+ assert(strlen(work) <= sizeof(work));
+#endif
for(fptr=work; *fptr; fptr++)
OUTCHAR(*fptr);
}
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