1 files changed, 59 insertions, 11 deletions

diff --git a/src/lib/confmgt/unitparse.c b/src/lib/confmgt/unitparse.c
index c3ed8285a4..61edc60694 100644
--- a/src/lib/confmgt/unitparse.c
+++ b/src/lib/confmgt/unitparse.c
@@ -1,7 +1,7 @@
 /* Copyright (c) 2001 Matej Pfajfar.
  * Copyright (c) 2001-2004, Roger Dingledine.
  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2019, The Tor Project, Inc. */
+ * Copyright (c) 2007-2020, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
 /**
@@ -13,8 +13,11 @@
 #include "lib/confmgt/unitparse.h"
 #include "lib/log/log.h"
 #include "lib/log/util_bug.h"
+#include "lib/malloc/malloc.h"
 #include "lib/string/parse_int.h"
+#include "lib/string/printf.h"
 #include "lib/string/util_string.h"
+#include "lib/intmath/muldiv.h"
 
 #include <string.h>
 
@@ -109,22 +112,30 @@ const struct unit_table_t time_msec_units[] = {
  * table <b>u</b>, then multiply the number by the unit multiplier.
  * On success, set *<b>ok</b> to 1 and return this product.
  * Otherwise, set *<b>ok</b> to 0.
+ *
+ * If an error (like overflow or a negative value is detected), put an error
+ * message in *<b>errmsg_out</b> if that pointer is non-NULL, and otherwise
+ * log a warning.
  */
 uint64_t
-config_parse_units(const char *val, const unit_table_t *u, int *ok)
+config_parse_units(const char *val, const unit_table_t *u, int *ok,
+                   char **errmsg_out)
 {
   uint64_t v = 0;
   double d = 0;
   int use_float = 0;
   char *cp;
+  char *errmsg = NULL;
 
   tor_assert(ok);
 
   v = tor_parse_uint64(val, 10, 0, UINT64_MAX, ok, &cp);
   if (!*ok || (cp && *cp == '.')) {
     d = tor_parse_double(val, 0, (double)UINT64_MAX, ok, &cp);
-    if (!*ok)
+    if (!*ok) {
+      tor_asprintf(&errmsg, "Unable to parse %s as a number", val);
       goto done;
+    }
     use_float = 1;
   }
 
@@ -142,18 +153,55 @@ config_parse_units(const char *val, const unit_table_t *u, int *ok)
 
   for ( ;u->unit;++u) {
     if (!strcasecmp(u->unit, cp)) {
-      if (use_float)
-        v = (uint64_t)(u->multiplier * d);
-      else
-        v *= u->multiplier;
+      if (use_float) {
+        d = u->multiplier * d;
+
+        if (d < 0) {
+          tor_asprintf(&errmsg, "Got a negative value while parsing %s %s",
+                       val, u->unit);
+          *ok = 0;
+          goto done;
+        }
+
+        // Some compilers may warn about casting a double to an unsigned type
+        // because they don't know if d is >= 0
+        if (d >= 0 && (d > (double)INT64_MAX || (uint64_t)d > INT64_MAX)) {
+          tor_asprintf(&errmsg, "Overflow while parsing %s %s",
+                       val, u->unit);
+          *ok = 0;
+          goto done;
+        }
+
+        v = (uint64_t) d;
+      } else {
+        v = tor_mul_u64_nowrap(v, u->multiplier);
+
+        if (v > INT64_MAX) {
+          tor_asprintf(&errmsg, "Overflow while parsing %s %s",
+                       val, u->unit);
+          *ok = 0;
+          goto done;
+        }
+      }
+
       *ok = 1;
       goto done;
     }
   }
-  log_warn(LD_CONFIG, "Unknown unit '%s'.", cp);
+  tor_asprintf(&errmsg, "Unknown unit in %s", val);
   *ok = 0;
  done:
 
+  if (errmsg) {
+    tor_assert_nonfatal(!*ok);
+    if (errmsg_out) {
+      *errmsg_out = errmsg;
+    } else {
+      log_warn(LD_CONFIG, "%s", errmsg);
+      tor_free(errmsg);
+    }
+  }
+
   if (*ok)
     return v;
   else
@@ -167,7 +215,7 @@ config_parse_units(const char *val, const unit_table_t *u, int *ok)
 uint64_t
 config_parse_memunit(const char *s, int *ok)
 {
-  uint64_t u = config_parse_units(s, memory_units, ok);
+  uint64_t u = config_parse_units(s, memory_units, ok, NULL);
   return u;
 }
 
@@ -179,7 +227,7 @@ int
 config_parse_msec_interval(const char *s, int *ok)
 {
   uint64_t r;
-  r = config_parse_units(s, time_msec_units, ok);
+  r = config_parse_units(s, time_msec_units, ok, NULL);
   if (r > INT_MAX) {
     log_warn(LD_CONFIG, "Msec interval '%s' is too long", s);
     *ok = 0;
@@ -196,7 +244,7 @@ int
 config_parse_interval(const char *s, int *ok)
 {
   uint64_t r;
-  r = config_parse_units(s, time_units, ok);
+  r = config_parse_units(s, time_units, ok, NULL);
   if (r > INT_MAX) {
     log_warn(LD_CONFIG, "Interval '%s' is too long", s);
     *ok = 0;