patch 9.0.2122: [security]: prevent overflow in indentingv9.0.2122

Problem:  [security]: prevent overflow in indenting
Solution: use long long and remove cast to (int)

The shiftwidth option values are defined as being long. However, when
calculating the actual amount of indent, we cast down to (int), which
may cause the shiftwidth value to become negative and later it may even
cause Vim to try to allocate a huge amount of memory.

We already use long and long long variable types to calculate the indent
(and detect possible overflows), so the cast to (int) seems superfluous
and can be safely removed. So let's just remove the (int) cast and
calculate the indent using longs.

Additionally, the 'shiftwidth' option value is also used when determining
the actual 'cino' options. There it can again cause another overflow, so
make sure it is safe in parse_cino() as well.

fixes: #13554
closes: #13555

Signed-off-by: Christian Brabandt <cb@256bit.org>

4 files changed, 69 insertions, 41 deletions

diff --git a/src/cindent.c b/src/cindent.c
index 9b2b6442a6..7ac1f4ba87 100644
--- a/src/cindent.c
+++ b/src/cindent.c
@@ -1730,10 +1730,17 @@ parse_cino(buf_T *buf)
     char_u	*p;
     char_u	*l;
     char_u	*digits;
-    int		n;
+    long long	n;
     int		divider;
     int		fraction = 0;
-    int		sw = (int)get_sw_value(buf);
+    int		sw;
+    long long	t = get_sw_value(buf);
+
+    // needed for cino-(, it will be multiplied by 2 again
+    if (t > INT_MAX / 2)
+	sw = INT_MAX / 2;
+    else
+	sw = (int)t;
 
     // Set the default values.
 
@@ -1902,47 +1909,52 @@ parse_cino(buf_T *buf)
 	if (l[1] == '-')
 	    n = -n;
 
+	if (n > INT_MAX)
+	    n = INT_MAX;
+	else if (n < INT_MIN)
+	    n = INT_MIN;
+
 	// When adding an entry here, also update the default 'cinoptions' in
 	// doc/indent.txt, and add explanation for it!
 	switch (*l)
 	{
-	    case '>': buf->b_ind_level = n; break;
-	    case 'e': buf->b_ind_open_imag = n; break;
-	    case 'n': buf->b_ind_no_brace = n; break;
-	    case 'f': buf->b_ind_first_open = n; break;
-	    case '{': buf->b_ind_open_extra = n; break;
-	    case '}': buf->b_ind_close_extra = n; break;
-	    case '^': buf->b_ind_open_left_imag = n; break;
-	    case 'L': buf->b_ind_jump_label = n; break;
-	    case ':': buf->b_ind_case = n; break;
-	    case '=': buf->b_ind_case_code = n; break;
-	    case 'b': buf->b_ind_case_break = n; break;
-	    case 'p': buf->b_ind_param = n; break;
-	    case 't': buf->b_ind_func_type = n; break;
-	    case '/': buf->b_ind_comment = n; break;
-	    case 'c': buf->b_ind_in_comment = n; break;
-	    case 'C': buf->b_ind_in_comment2 = n; break;
-	    case 'i': buf->b_ind_cpp_baseclass = n; break;
-	    case '+': buf->b_ind_continuation = n; break;
-	    case '(': buf->b_ind_unclosed = n; break;
-	    case 'u': buf->b_ind_unclosed2 = n; break;
-	    case 'U': buf->b_ind_unclosed_noignore = n; break;
-	    case 'W': buf->b_ind_unclosed_wrapped = n; break;
-	    case 'w': buf->b_ind_unclosed_whiteok = n; break;
-	    case 'm': buf->b_ind_matching_paren = n; break;
-	    case 'M': buf->b_ind_paren_prev = n; break;
-	    case ')': buf->b_ind_maxparen = n; break;
-	    case '*': buf->b_ind_maxcomment = n; break;
-	    case 'g': buf->b_ind_scopedecl = n; break;
-	    case 'h': buf->b_ind_scopedecl_code = n; break;
-	    case 'j': buf->b_ind_java = n; break;
-	    case 'J': buf->b_ind_js = n; break;
-	    case 'l': buf->b_ind_keep_case_label = n; break;
-	    case '#': buf->b_ind_hash_comment = n; break;
-	    case 'N': buf->b_ind_cpp_namespace = n; break;
-	    case 'k': buf->b_ind_if_for_while = n; break;
-	    case 'E': buf->b_ind_cpp_extern_c = n; break;
-	    case 'P': buf->b_ind_pragma = n; break;
+	    case '>': buf->b_ind_level = (int)n; break;
+	    case 'e': buf->b_ind_open_imag = (int)n; break;
+	    case 'n': buf->b_ind_no_brace = (int)n; break;
+	    case 'f': buf->b_ind_first_open = (int)n; break;
+	    case '{': buf->b_ind_open_extra = (int)n; break;
+	    case '}': buf->b_ind_close_extra = (int)n; break;
+	    case '^': buf->b_ind_open_left_imag = (int)n; break;
+	    case 'L': buf->b_ind_jump_label = (int)n; break;
+	    case ':': buf->b_ind_case = (int)n; break;
+	    case '=': buf->b_ind_case_code = (int)n; break;
+	    case 'b': buf->b_ind_case_break = (int)n; break;
+	    case 'p': buf->b_ind_param = (int)n; break;
+	    case 't': buf->b_ind_func_type = (int)n; break;
+	    case '/': buf->b_ind_comment = (int)n; break;
+	    case 'c': buf->b_ind_in_comment = (int)n; break;
+	    case 'C': buf->b_ind_in_comment2 = (int)n; break;
+	    case 'i': buf->b_ind_cpp_baseclass = (int)n; break;
+	    case '+': buf->b_ind_continuation = (int)n; break;
+	    case '(': buf->b_ind_unclosed = (int)n; break;
+	    case 'u': buf->b_ind_unclosed2 = (int)n; break;
+	    case 'U': buf->b_ind_unclosed_noignore = (int)n; break;
+	    case 'W': buf->b_ind_unclosed_wrapped = (int)n; break;
+	    case 'w': buf->b_ind_unclosed_whiteok = (int)n; break;
+	    case 'm': buf->b_ind_matching_paren = (int)n; break;
+	    case 'M': buf->b_ind_paren_prev = (int)n; break;
+	    case ')': buf->b_ind_maxparen = (int)n; break;
+	    case '*': buf->b_ind_maxcomment = (int)n; break;
+	    case 'g': buf->b_ind_scopedecl = (int)n; break;
+	    case 'h': buf->b_ind_scopedecl_code = (int)n; break;
+	    case 'j': buf->b_ind_java = (int)n; break;
+	    case 'J': buf->b_ind_js = (int)n; break;
+	    case 'l': buf->b_ind_keep_case_label = (int)n; break;
+	    case '#': buf->b_ind_hash_comment = (int)n; break;
+	    case 'N': buf->b_ind_cpp_namespace = (int)n; break;
+	    case 'k': buf->b_ind_if_for_while = (int)n; break;
+	    case 'E': buf->b_ind_cpp_extern_c = (int)n; break;
+	    case 'P': buf->b_ind_pragma = (int)n; break;
 	}
 	if (*p == ',')
 	    ++p;
diff --git a/src/ops.c b/src/ops.c
index 9e8ea86160..7cb82b89fb 100644
--- a/src/ops.c
+++ b/src/ops.c
@@ -230,8 +230,8 @@ shift_line(
     int call_changed_bytes)	// call changed_bytes()
 {
     long long	count;
-    int		i, j;
-    int		sw_val = (int)get_sw_value_indent(curbuf);
+    long	i, j;
+    long	sw_val = get_sw_value_indent(curbuf);
 
     count = (long long)get_indent();	// get current indent
 
diff --git a/src/testdir/test_indent.vim b/src/testdir/test_indent.vim
index 217a7ae625..a7e9f425c9 100644
--- a/src/testdir/test_indent.vim
+++ b/src/testdir/test_indent.vim
@@ -286,4 +286,18 @@ func Test_indent_overflow_count()
   close!
 endfunc
 
+func Test_indent_overflow_count2()
+  new
+  " this only works, when long is 64bits
+  try
+    setl sw=0x180000000
+  catch /^Vim\%((\a\+)\)\=:E487:/
+  throw 'Skipped: value negative on this platform'
+  endtry
+  call setline(1, "\tabc")
+  norm! <<
+  call assert_equal(0, indent(1))
+  close!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/src/version.c b/src/version.c
index 642da01d8b..9b7fbe7229 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2122,
+/**/
     2121,
 /**/
     2120,