Re: Remaining memory corruption bugs in readline

[dualbus]

On Fri, Jun 02, 2017 at 12:07:34AM -0500, dualbus wrote:
[...]
> #1 _rl_get_char_len / update_line
[...]
>   ==5781==ERROR: AddressSanitizer: heap-buffer-overflow on address 
> 0x61900000cc80 at pc 0x7f400d00b063 bp 0x7ffcbce72250 sp 0x7ffcbce71a00
>   READ of size 851 at 0x61900000cc80 thread T0
>       #0 0x7f400d00b062  (/usr/lib/x86_64-linux-gnu/libasan.so.3+0x3c062)
>       #1 0x559b50a04821 in _rl_get_char_len 
> ../../../bash/lib/readline/mbutil.c:223
>       #2 0x559b50a048e0 in _rl_compare_chars 
> ../../../bash/lib/readline/mbutil.c:252
>       #3 0x559b509db526 in update_line 
> ../../../bash/lib/readline/display.c:1664
[...]

I have been looking at this specific example for some time now.

The problem is that _rl_get_char_len assumes it's being called with a
\0-terminated string, but under some cases (that I haven't been able to
figure out), there's no \0 at the end, so the strlen reads more than it
should.

-- 
Eduardo Bustamante
https://dualbus.me/