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 f6e331d..278bf25 100644 (file)
--- a/src/internal/floatscan.c
+++ b/src/internal/floatscan.c
@@ -15,12 +15,20 @@
 #define LD_B1B_MAX 9007199, 254740991
 #define KMAX 128
 
-#else /* LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 */
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
 
 #define LD_B1B_DIG 3
 #define LD_B1B_MAX 18, 446744073, 709551615
 #define KMAX 2048
 
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
+
+#define LD_B1B_DIG 4
+#define LD_B1B_MAX 10384593, 717069655, 257060992, 658440191
+#define KMAX 2048
+
+#else
+#error Unsupported long double representation
 #endif
 
 #define MASK (KMAX-1)
@@ -102,7 +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;
@@ -164,6 +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;