fix undefined behavior in strto* via FILE buffer pointer abuse

[musl] / src / internal / floatscan.c

diff --git a/src/internal/floatscan.c b/src/internal/floatscan.c
index eef70df..278bf25 100644 (file)
--- a/src/internal/floatscan.c
+++ b/src/internal/floatscan.c
@@ -110,7 +110,10 @@ static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int po
                        gotdig=1;
                } else {
                        dc++;
-                       if (c!='0') x[KMAX-4] |= 1;
+                       if (c!='0') {
+                               lnz = (KMAX-4)*9;
+                               x[KMAX-4] |= 1;
+                       }
                }
        }
        if (!gotrad) lrp=dc;
@@ -172,6 +175,9 @@ static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int po
                        return sign * (long double)x[0] * p10s[rp-10];
        }
 
+       /* Drop trailing zeros */
+       for (; !x[z-1]; z--);
+
        /* Align radix point to B1B digit boundary */
        if (rp % 9) {
                int rpm9 = rp>=0 ? rp%9 : rp%9+9;