postgres.git / summary / log / commit / refs

commit    4868e4468590bc32f9c3afed4ec795d6a7732c9d
Author:   Andres Freund <andres@anarazel.de>
Date:     Wed Oct 03 20:02:25 2018 +0000
First released in: 12.0

    Ensure that snprintf.c's fmtint() doesn't overflow when printing INT64_MIN.
    
    This isn't actually a live bug, as the output happens to be the
    same.  But it upsets tools like UBSan, which makes it worthwhile to
    fix.
    
    As it's an issue without practical consequences, don't backpatch.
    
    Author: Andres Freund
    Discussion: https://postgr.es/m/20180928001121.hhx5n6dsygqxr5wu@alap3.anarazel.de


 src/port/snprintf.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/port/snprintf.c b/src/port/snprintf.c
index 3bd598d75c6..872d8001240 100644
--- a/src/port/snprintf.c
+++ b/src/port/snprintf.c
@@ -1007,6 +1007,7 @@ fmtint(long long value, char type, int forcesign, int leftjust,
 	   PrintfTarget *target)
 {
 	unsigned long long base;
+	unsigned long long uvalue;
 	int			dosign;
 	const char *cvt = "0123456789abcdef";
 	int			signvalue = 0;
@@ -1045,7 +1046,9 @@ fmtint(long long value, char type, int forcesign, int leftjust,
 
 	/* Handle +/- */
 	if (dosign && adjust_sign((value < 0), forcesign, &signvalue))
-		value = -value;
+		uvalue = -(uint64) value;
+	else
+		uvalue = (uint64) value;
 
 	/*
 	 * SUS: the result of converting 0 with an explicit precision of 0 is no
@@ -1056,8 +1059,6 @@ fmtint(long long value, char type, int forcesign, int leftjust,
 	else
 	{
 		/* make integer string */
-		unsigned long long uvalue = (unsigned long long) value;
-
 		do
 		{
 			convert[sizeof(convert) - (++vallen)] = cvt[uvalue % base];


[parent: 9a3cebeaa7fd]