This is the mail archive of the mailing list for the GDB project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[binutils-gdb] gdb: Avoid signed integer overflow when printing source lines

*** TEST RESULTS FOR COMMIT 0e2a21335b6fc4a5b6bed19d9623916c52918b72 ***

Author: Andrew Burgess <>
Branch: master
Commit: 0e2a21335b6fc4a5b6bed19d9623916c52918b72

gdb: Avoid signed integer overflow when printing source lines

When printing source lines with calls to print_source_lines we need to
pass a start line number and an end line number.  The end line number
is calculated by calling get_lines_to_list and adding this value to
the start line number.  For example this code from list_command:

    print_source_lines (cursal.symtab, first,
                        first + get_lines_to_list (), 0);

The problem is that get_lines_to_list returns a value based on the
GDB setting `set listsize LISTSIZE`.  By default LISTSIZE is 10,
however, its also possible to set LISTSIZE to unlimited, in which
case get_lines_to_list will return INT_MAX.

As the parameter signature for print_source_lines is:

  void print_source_lines (struct symtab *, int, int,

and `first` in the above code is an `int`, then when LISTSIZE is
`unlimited` the above code will result in signed integer overflow,
which is undefined.

The solution in this patch is a new class source_lines_range that can
be constructed from a single line number and a direction (forward or
backward).  The range is then constructed from the line number and the
value of get_lines_to_list.


	* cli/cli-cmds.c (list_command): Pass a source_lines_range to
	* source.c (print_source_lines_base): Update line number check.
	(print_source_lines): New function.
	(source_lines_range::source_lines_range): New function.
	* source.h (class source_lines_range): New class.
	(print_source_lines): New declaration.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]