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[PING][PATCH][readline] Fix heap-buffer-overflow in update_line
- From: Tom de Vries <tdevries at suse dot de>
- To: gdb-patches at sourceware dot org
- Cc: chet dot ramey at case dot edu
- Date: Mon, 10 Jun 2019 20:36:32 +0200
- Subject: [PING][PATCH][readline] Fix heap-buffer-overflow in update_line
- References: <20190525112458.GA3838@delia>
On 25-05-19 13:24, Tom de Vries wrote:
> Hi,
>
> When:
> - building trunk gdb with '-fsanitize=address -lasan',
> - running gdb tests with "export ASAN_OPTIONS=detect_leaks=0",
> I run into a heap-buffer-overflow failure for
> gdb.base/utf8-identifiers.exp.
>
> In more detail, the libasan error report looks like this:
> ...
> =================================================================
> ==22340==ERROR: AddressSanitizer: heap-buffer-overflow on address
> 0x619000054a80 at pc 0x7fcd0306b4c9 bp 0x7fffb1a8d880 sp 0x7fffb1a8d030
> READ of size 32766 at 0x619000054a80 thread T0
> #0 0x7fcd0306b4c8 (/usr/lib64/libasan.so.4+0xae4c8)
> #1 0x15f12a1 in update_line
> /data/gdb_versions/devel/src/readline/display.c:1377
> #2 0x15f03cb in rl_redisplay
> /data/gdb_versions/devel/src/readline/display.c:1204
> #3 0x15bf932 in readline_internal_setup
> /data/gdb_versions/devel/src/readline/readline.c:394
> #4 0x15fe723 in _rl_callback_newline
> /data/gdb_versions/devel/src/readline/callback.c:89
> #5 0x15fe7ef in rl_callback_handler_install
> /data/gdb_versions/devel/src/readline/callback.c:102
> #6 0xd7bce6 in gdb_rl_callback_handler_install(char const*)
> /data/gdb_versions/devel/src/gdb/event-top.c:319
> #7 0xd7c0c6 in display_gdb_prompt(char const*)
> /data/gdb_versions/devel/src/gdb/event-top.c:409
> #8 0xd7d6c1 in command_line_handler(std::unique_ptr<char,
> gdb::xfree_deleter<char> >&&)
> /data/gdb_versions/devel/src/gdb/event-top.c:776
> #9 0xd7b92a in gdb_rl_callback_handler
> /data/gdb_versions/devel/src/gdb/event-top.c:217
> #10 0x15ff479 in rl_callback_read_char
> /data/gdb_versions/devel/src/readline/callback.c:220
> #11 0xd7b4d5 in gdb_rl_callback_read_char_wrapper_noexcept
> /data/gdb_versions/devel/src/gdb/event-top.c:175
> #12 0xd7b6b5 in gdb_rl_callback_read_char_wrapper
> /data/gdb_versions/devel/src/gdb/event-top.c:192
> #13 0xd7c8aa in stdin_event_handler(int, void*)
> /data/gdb_versions/devel/src/gdb/event-top.c:514
> #14 0xd76ca7 in handle_file_event
> /data/gdb_versions/devel/src/gdb/event-loop.c:731
> #15 0xd7751f in gdb_wait_for_event
> /data/gdb_versions/devel/src/gdb/event-loop.c:857
> #16 0xd7547e in gdb_do_one_event()
> /data/gdb_versions/devel/src/gdb/event-loop.c:321
> #17 0xd75526 in start_event_loop()
> /data/gdb_versions/devel/src/gdb/event-loop.c:370
> #18 0x101b04c in captured_command_loop
> /data/gdb_versions/devel/src/gdb/main.c:331
> #19 0x101de73 in captured_main
> /data/gdb_versions/devel/src/gdb/main.c:1173
> #20 0x101df03 in gdb_main(captured_main_args*)
> /data/gdb_versions/devel/src/gdb/main.c:1188
> #21 0x872dba in main /data/gdb_versions/devel/src/gdb/gdb.c:32
> #22 0x7fcd00f2ff49 in __libc_start_main (/lib64/libc.so.6+0x20f49)
> #23 0x872bc9 in _start (/data/gdb_versions/devel/build/gdb/gdb+0x872bc9)
>
> 0x619000054a80 is located 0 bytes to the right of 1024-byte region
> [0x619000054680,0x619000054a80)
> allocated by thread T0 here:
> #0 0x7fcd03099510 in malloc (/usr/lib64/libasan.so.4+0xdc510)
> #1 0xae0078 in xmalloc
> /data/gdb_versions/devel/src/gdb/common/common-utils.c:44
> #2 0x15eaccb in init_line_structures
> /data/gdb_versions/devel/src/readline/display.c:458
> #3 0x15eb4d8 in rl_redisplay
> /data/gdb_versions/devel/src/readline/display.c:526
> #4 0x15bf932 in readline_internal_setup
> /data/gdb_versions/devel/src/readline/readline.c:394
> #5 0x15fe723 in _rl_callback_newline
> /data/gdb_versions/devel/src/readline/callback.c:89
> #6 0x15fe7ef in rl_callback_handler_install
> /data/gdb_versions/devel/src/readline/callback.c:102
> #7 0xd7bce6 in gdb_rl_callback_handler_install(char const*)
> /data/gdb_versions/devel/src/gdb/event-top.c:319
> #8 0xd7c0c6 in display_gdb_prompt(char const*)
> /data/gdb_versions/devel/src/gdb/event-top.c:409
> #9 0xaa041b in cli_interp_base::pre_command_loop()
> /data/gdb_versions/devel/src/gdb/cli/cli-interp.c:286
> #10 0xf5342a in interp_pre_command_loop(interp*)
> /data/gdb_versions/devel/src/gdb/interps.c:320
> #11 0x101b047 in captured_command_loop
> /data/gdb_versions/devel/src/gdb/main.c:328
> #12 0x101de73 in captured_main
> /data/gdb_versions/devel/src/gdb/main.c:1173
> #13 0x101df03 in gdb_main(captured_main_args*)
> /data/gdb_versions/devel/src/gdb/main.c:1188
> #14 0x872dba in main /data/gdb_versions/devel/src/gdb/gdb.c:32
> #15 0x7fcd00f2ff49 in __libc_start_main (/lib64/libc.so.6+0x20f49)
>
> SUMMARY: AddressSanitizer: heap-buffer-overflow
> (/usr/lib64/libasan.so.4+0xae4c8)
> Shadow bytes around the buggy address:
> 0x0c3280002900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c3280002910: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c3280002920: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c3280002930: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c3280002940: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> =>0x0c3280002950:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x0c3280002960: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> 0x0c3280002970: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c3280002980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c3280002990: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 0x0c32800029a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> Shadow byte legend (one shadow byte represents 8 application bytes):
> Addressable: 00
> Partially addressable: 01 02 03 04 05 06 07
> Heap left redzone: fa
> Freed heap region: fd
> Stack left redzone: f1
> Stack mid redzone: f2
> Stack right redzone: f3
> Stack after return: f5
> Stack use after scope: f8
> Global redzone: f9
> Global init order: f6
> Poisoned by user: f7
> Container overflow: fc
> Array cookie: ac
> Intra object redzone: bb
> ASan internal: fe
> Left alloca redzone: ca
> Right alloca redzone: cb
> ==22340==ABORTING
> ...
>
> I've written an assert in rl_redisplay that formulates the error condition:
> ...
> @@ -1387,6 +1389,10 @@ rl_redisplay (void)
> cpos_adjusted = 0;
> + assert (last_lmargin + (_rl_screenwidth + visible_wrap_offset)
> + <= line_size);
> + assert (lmargin + (_rl_screenwidth + (lmargin ? 0 : wrap_offset))
> + <= line_size);
> update_line (&visible_line[last_lmargin],
> &invisible_line[lmargin],
> 0,
> _rl_screenwidth + visible_wrap_offset,
> _rl_screenwidth + (lmargin ? 0 : wrap_offset),
> 0);
> ...
> which triggers without needing the address sanitizer (or even an executable),
> like this:
> ...
> $ TERM=dumb gdb -q -ex "set width 0"
> gdb: src/display.c:1393: rl_redisplay: Assertion
> `last_lmargin + (_rl_screenwidth + visible_wrap_offset) <= line_size'
> failed.
> Aborted (core dumped)
> ...
>
> The basic problem is this: visible_line and invisible_line have length
> line_size, but the update_line call assumes that line_size is at least
> _rl_screenwidth + 1. Executing "set width 0" sets _rl_screenwidth to 32766 but
> doesn't affect line_size, which is initialized to 1024.
>
> Fix this by ensuring in init_line_structures and rl_redisplay that line_size
> is at least _rl_screenwidth + 1.
>
> Tested on x86_64-linux.
>
> Reviewed by readline maintainer (
> https://sourceware.org/ml/gdb-patches/2019-05/msg00566.html ).
>
> OK for binutils-gdb repo copy of readline?
>
Ping.
Thanks,
- Tom
> [readline] Fix heap-buffer-overflow in update_line
>
> readline/ChangeLog.gdb:
>
> 2019-05-25 Tom de Vries <tdevries@suse.de>
> Chet Ramey <chet.ramey@case.edu>
>
> PR cli/24514
> * readline/display.c (init_line_structures, rl_redisplay): Ensure
> line_size is at least _rl_screenwidth + 1.
>
> ---
> readline/display.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/readline/display.c b/readline/display.c
> index 9044305797..842adf5067 100644
> --- a/readline/display.c
> +++ b/readline/display.c
> @@ -450,6 +450,9 @@ init_line_structures (minsize)
> {
> register int n;
>
> + if (minsize <= _rl_screenwidth) /* XXX - for gdb */
> + minsize = _rl_screenwidth + 1;
> +
> if (invisible_line == 0) /* initialize it */
> {
> if (line_size < minsize)
> @@ -526,6 +529,8 @@ rl_redisplay ()
> init_line_structures (0);
> rl_on_new_line ();
> }
> + else if (line_size <= _rl_screenwidth)
> + init_line_structures (_rl_screenwidth + 1);
>
> /* Draw the line into the buffer. */
> cpos_buffer_position = -1;
>