check for safe arguments, raising error when invalid (fix #17720)

1 files changed, 53 insertions, 3 deletions

diff --git a/rts/RtsFlags.c b/rts/RtsFlags.c
index fe118ea5f0..5b594c915d 100644
--- a/rts/RtsFlags.c
+++ b/rts/RtsFlags.c
@@ -21,7 +21,10 @@
 #include <ctype.h>
 #endif
 
+#include <errno.h>
+
 #include <string.h>
+#include <stdlib.h>
 
 #if defined(HAVE_UNISTD_H)
 #include <unistd.h>
@@ -98,6 +101,9 @@ static int  openStatsFile (
 static StgWord64 decodeSize (
     const char *flag, uint32_t offset, StgWord64 min, StgWord64 max);
 
+static double parseDouble (
+    const char *arg, bool *error);
+
 static void bad_option (const char *s);
 
 #if defined(DEBUG)
@@ -1326,8 +1332,13 @@ error = true;
                 if (rts_argv[arg][2] == '\0') {
                   /* use default */
                 } else {
+                    double intervalSeconds = parseDouble(rts_argv[arg]+2, &error);
+
+                    if (error) {
+                        errorBelch("bad value for -i");
+                    }
                     RtsFlags.ProfFlags.heapProfileInterval =
-                        fsecondsToTime(atof(rts_argv[arg]+2));
+                        fsecondsToTime(intervalSeconds);
                 }
                 break;
 
@@ -1337,8 +1348,13 @@ error = true;
                 if (rts_argv[arg][2] == '\0')
                     RtsFlags.ConcFlags.ctxtSwitchTime = 0;
                 else {
+                    double intervalSeconds = parseDouble(rts_argv[arg]+2, &error);
+
+                    if (error) {
+                        errorBelch("bad value for -C");
+                    }
                     RtsFlags.ConcFlags.ctxtSwitchTime =
-                        fsecondsToTime(atof(rts_argv[arg]+2));
+                        fsecondsToTime(intervalSeconds);
                 }
                 break;
 
@@ -1348,8 +1364,13 @@ error = true;
                     // turns off ticks completely
                     RtsFlags.MiscFlags.tickInterval = 0;
                 } else {
+                    double intervalSeconds = parseDouble(rts_argv[arg]+2, &error);
+
+                    if (error) {
+                        errorBelch("bad value for -V");
+                    }
                     RtsFlags.MiscFlags.tickInterval =
-                        fsecondsToTime(atof(rts_argv[arg]+2));
+                        fsecondsToTime(intervalSeconds);
                 }
                 break;
 
@@ -1912,6 +1933,35 @@ decodeSize(const char *flag, uint32_t offset, StgWord64 min, StgWord64 max)
     return val;
 }
 
+/* ----------------------------------------------------------------------------------
+ * parseDouble: parse a double from a string, setting a flag in case of an error
+-------------------------------------------------------------------------------- */
+
+static double
+parseDouble(const char *arg, bool *error)
+{
+    char *endptr;
+    double out;
+    errno = 0;
+
+    out = strtod(arg, &endptr);
+
+    if (errno != 0 || endptr == arg) {
+        *error = true;
+        return out;
+    }
+
+    while (isspace((unsigned char)*endptr)) {
+        ++endptr;
+    }
+
+    if (*endptr != 0) {
+        *error = true;
+    }
+
+    return out;
+}
+
 #if defined(DEBUG)
 static void read_debug_flags(const char* arg)
 {