binutils-gdb

Branch: master

History

Tom de Vries 85f4cf41a8 [readline] Fix double free in _rl_scxt_dispose Consider the following scenario. We start gdb in TUI mode: ... $ gdb -q -tui ... and type ^R which gives us the reverse-isearch prompt in the cmd window: ... (reverse-i-search)`': ... and then type "foo", right-arrow-key, and ^C. In TUI mode, gdb uses a custom rl_getc_function tui_getc. When pressing the right-arrow-key, tui_getc: - attempts to scroll the TUI src window, without any effect, and - returns 0. The intention of returning 0 is mentioned here in tui_dispatch_ctrl_char: ... /* We intercepted the control character, so return 0 (which readline will interpret as a no-op). / return 0; ... However, after this 0 is returned by the rl_read_key () call in _rl_search_getchar, _rl_read_mbstring is called, which incorrectly interprets 0 as the first part of an utf-8 multibyte char, and tries to read the next char. In this state, the ^C takes effect and we run into a double free because _rl_isearch_cleanup is called twice. Both these issues need fixing independently, though after fixing the first we no longer trigger the second. The first issue is caused by the subtle difference between: - a char array containing 0 chars, which is zero-terminated, and - a char array containing 1 char, which is zero. In mbrtowc terms, this is the difference between: ... mbrtowc (&wc, "", 0, &ps); ... which returns -2, and: ... mbrtowc (&wc, "", 1, &ps); ... which returns 0. Note that _rl_read_mbstring calls _rl_get_char_len without passing it an explicit length parameter, and consequently it cannot distinguish between the two, and defaults to the "0 chars" choice. Note that the same problem doesn't exist in _rl_read_mbchar. Fix this by defaulting to the "1 char" choice in _rl_get_char_len: ... - if (_rl_utf8locale && l > 0 && UTF8_SINGLEBYTE(src)) + if (_rl_utf8locale && l >= 0 && UTF8_SINGLEBYTE(*src)) ... The second problem happens when the call to _rl_search_getchar in _rl_isearch_callback returns. At that point _rl_isearch_cleanup has already been called from the signal handler, but we proceed regardless, using a cxt pointer that has been freed. Fix this by checking for "RL_ISSTATE (RL_STATE_ISEARCH)" after the call to _rl_search_getchar: ... c = _rl_search_getchar (cxt); + if (!RL_ISSTATE (RL_STATE_ISEARCH)) + return 1; ... Tested on x86_64-linux. Approved-By: Chet Ramey <chet.ramey@case.edu> PR tui/30056 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30056		3 years ago
..
readline	[readline] Fix double free in _rl_scxt_dispose	3 years ago
.gitignore	Move readline to the readline/readline subdirectory	7 years ago
ChangeLog	Update config.sub and config.guess for MIPS R3 and R5 ISA support	5 years ago
Makefile.am	Minor updates to readline configury	6 years ago
Makefile.in	Minor updates to readline configury	6 years ago
README	Update readline/README to mention patchlevel	6 years ago
aclocal.m4	Move readline to the readline/readline subdirectory	7 years ago
configure	Minor updates to readline configury	6 years ago
configure.ac	Minor updates to readline configury	6 years ago

README

This is an import of readline that is used by gdb.

To send patches, follow the gdb patch submission instructions in
../gdb/CONTRIBUTE.  For maintainers, see ../gdb/MAINTAINERS.

If you need to patch readline, please document the changes here.

To import, copy the upstream readline sources into the "readline"
subdirectory, remembering to (1) remove any files that were deleted
upstream, and (2) merge the one small configure.ac patch that gdb
carries.

If your import removes the need for a local patch, please remember to
update this file.

Individual upstream readline patches can be directly imported using
"git am".  You can see the current patch level by looking at
readline/patchlevel.