load: Check for integer and real overlfows and underflows

[jansson.git] / src / load.c

diff --git a/src/load.c b/src/load.c
index 25df182..5175f35 100644 (file)
--- a/src/load.c
+++ b/src/load.c
@@ -8,6 +8,7 @@
 #define _GNU_SOURCE
 #include <ctype.h>
 #include <errno.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -134,10 +135,7 @@ static char stream_get(stream_t *stream, json_error_t *error)
 
         c = stream->buffer[0];
 
-        if(c == EOF && stream->eof(stream->data))
-            return EOF;
-
-        if(c < 0)
+        if(c < 0 && c != EOF)
         {
             /* multi-byte UTF-8 sequence */
             int i, count;
@@ -257,11 +255,11 @@ static void lex_scan_string(lex_t *lex, json_error_t *error)
     lex->value.string = NULL;
     lex->token = TOKEN_INVALID;
 
-    /* skip the " */
     c = lex_get_save(lex, error);
 
     while(c != '"') {
         if(c == EOF) {
+            lex_unget_unsave(lex, c);
             if(lex_eof(lex))
                 error_set(error, lex, "premature end of input");
             goto out;
@@ -402,10 +400,11 @@ out:
     free(lex->value.string);
 }
 
-static void lex_scan_number(lex_t *lex, char c, json_error_t *error)
+static int lex_scan_number(lex_t *lex, char c, json_error_t *error)
 {
     const char *saved_text;
     char *end;
+    double value;
 
     lex->token = TOKEN_INVALID;
 
@@ -426,14 +425,26 @@ static void lex_scan_number(lex_t *lex, char c, json_error_t *error)
     }
 
     if(c != '.' && c != 'E' && c != 'e') {
+        long value;
+
         lex_unget_unsave(lex, c);
-        lex->token = TOKEN_INTEGER;
 
         saved_text = strbuffer_value(&lex->saved_text);
-        lex->value.integer = strtol(saved_text, &end, 10);
+        value = strtol(saved_text, &end, 10);
         assert(end == saved_text + lex->saved_text.length);
 
-        return;
+        if((value == LONG_MAX && errno == ERANGE) || value > INT_MAX) {
+            error_set(error, lex, "too big integer");
+            goto out;
+        }
+        else if((value == LONG_MIN && errno == ERANGE) || value < INT_MIN) {
+            error_set(error, lex, "too big negative integer");
+            goto out;
+        }
+
+        lex->token = TOKEN_INTEGER;
+        lex->value.integer = (int)value;
+        return 0;
     }
 
     if(c == '.') {
@@ -463,14 +474,29 @@ static void lex_scan_number(lex_t *lex, char c, json_error_t *error)
     }
 
     lex_unget_unsave(lex, c);
-    lex->token = TOKEN_REAL;
 
     saved_text = strbuffer_value(&lex->saved_text);
-    lex->value.real = strtod(saved_text, &end);
+    value = strtod(saved_text, &end);
     assert(end == saved_text + lex->saved_text.length);
 
+    if(value == 0 && errno == ERANGE) {
+        error_set(error, lex, "real number underflow");
+        goto out;
+    }
+
+    /* Cannot test for +/-HUGE_VAL because the HUGE_VAL constant is
+       only defined in C99 mode. So let's trust in sole errno. */
+    else if(errno == ERANGE) {
+        error_set(error, lex, "real number overflow");
+        goto out;
+    }
+
+    lex->token = TOKEN_REAL;
+    lex->value.real = value;
+    return 0;
+
 out:
-    return;
+    return -1;
 }
 
 static int lex_scan(lex_t *lex, json_error_t *error)
@@ -509,8 +535,10 @@ static int lex_scan(lex_t *lex, json_error_t *error)
     else if(c == '"')
         lex_scan_string(lex, error);
 
-    else if(isdigit(c) || c == '-')
-        lex_scan_number(lex, c, error);
+    else if(isdigit(c) || c == '-') {
+        if(lex_scan_number(lex, c, error))
+            goto out;
+    }
 
     else if(isupper(c) || islower(c)) {
         /* eat up the whole identifier for clearer error messages */