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author | Paul Eggert <eggert@cs.ucla.edu> | 2014-09-07 00:04:01 -0700 |
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committer | Paul Eggert <eggert@cs.ucla.edu> | 2014-09-07 00:04:01 -0700 |
commit | b3bf18b3b87ac8f00857b8bfc3f2c74cf0e2fb7d (patch) | |
tree | cf138164e4f8887394f52cb22da594d1713da316 /src/callproc.c | |
parent | 930fb80f9e2815e599eb1de699668d42e305fa21 (diff) | |
download | emacs-b3bf18b3b87ac8f00857b8bfc3f2c74cf0e2fb7d.tar.gz |
Use SAFE_ALLOCA etc. to avoid unbounded stack allocation.
This follows up on the recent thread in emacs-devel on alloca; see:
http://lists.gnu.org/archive/html/emacs-devel/2014-09/msg00042.html
This patch also cleans up alloca-related glitches noted while
examining the code looking for unbounded alloca.
* alloc.c (listn):
* callproc.c (init_callproc):
Rewrite to avoid need for alloca.
* buffer.c (mouse_face_overlay_overlaps)
(report_overlay_modification):
* buffer.h (GET_OVERLAYS_AT):
* coding.c (make_subsidiaries):
* doc.c (Fsnarf_documentation):
* editfns.c (Fuser_full_name):
* fileio.c (Ffile_name_directory, Fexpand_file_name)
(search_embedded_absfilename, Fsubstitute_in_file_name):
* fns.c (Fmake_hash_table):
* font.c (font_vconcat_entity_vectors, font_update_drivers):
* fontset.c (fontset_pattern_regexp, Ffontset_info):
* frame.c (Fmake_terminal_frame, x_set_frame_parameters)
(xrdb_get_resource, x_get_resource_string):
* ftfont.c (ftfont_get_charset, ftfont_check_otf, ftfont_drive_otf):
* ftxfont.c (ftxfont_draw):
* image.c (xbm_load, xpm_load, jpeg_load_body):
* keyboard.c (echo_add_key, menu_bar_items, tool_bar_items):
* keymap.c (Fdescribe_buffer_bindings, describe_map):
* lread.c (openp):
* menu.c (digest_single_submenu, find_and_call_menu_selection)
(find_and_return_menu_selection):
* print.c (PRINTFINISH):
* process.c (Fformat_network_address):
* scroll.c (do_scrolling, do_direct_scrolling, scrolling_1):
* search.c (search_buffer, Fmatch_data, Fregexp_quote):
* sound.c (wav_play, au_play):
* syntax.c (skip_chars):
* term.c (tty_menu_activate, tty_menu_show):
* textprop.c (get_char_property_and_overlay):
* window.c (Fset_window_configuration):
* xdisp.c (safe__call, next_overlay_change, vmessage)
(compute_overhangs_and_x, draw_glyphs, note_mouse_highlight):
* xfaces.c (face_at_buffer_position):
* xmenu.c (x_menu_show):
Use SAFE_ALLOCA etc. instead of plain alloca, since the
allocation size isn't bounded.
* callint.c (Fcall_interactively): Redo memory_full check
so that it can be done at compile-time on some platforms.
* coding.c (MAX_LOOKUP_MAX): New constant.
(get_translation_table): Use it.
* callproc.c (call_process): Use SAFE_NALLOCA instead of
SAFE_ALLOCA, to catch integer overflows on size calculation.
(exec_failed) [!DOS_NT]: New function.
(child_setup) [!DOS_NT]: Use it.
* editfns.c (Ftranspose_regions):
Hoist USE_SAFE_ALLOC + SAFE_FREE out of 'if'.
* editfns.c (check_translation):
Allocate larger buffers on the heap.
* eval.c (internal_lisp_condition_case):
Check for MAX_ALLOCA overflow.
* fns.c (sort_vector): Use SAFE_ALLOCA_LISP rather than Fmake_vector.
(Fbase64_encode_region, Fbase64_decode_region):
Avoid unnecessary calls to SAFE_FREE before 'error'.
* buffer.c (mouse_face_overlay_overlaps):
* editfns.c (Fget_pos_property, check_translation):
* eval.c (Ffuncall):
* font.c (font_unparse_xlfd, font_find_for_lface):
* ftfont.c (ftfont_drive_otf):
* keyboard.c (echo_add_key, read_decoded_event_from_main_queue)
(menu_bar_items, tool_bar_items):
* sound.c (Fplay_sound_internal):
* xdisp.c (load_overlay_strings, dump_glyph_row):
Use an ordinary auto buffer rather than alloca, since the
allocation size is fixed and small.
* ftfont.c: Include <c-strcase.h>.
(matching_prefix): New function.
(get_adstyle_property): Use it, to avoid need for alloca.
* keyboard.c (echo_add_key):
* keymap.c (describe_map): Use ptrdiff_t, not int.
* keyboard.c (echo_add_key): Prefer sizeof to strlen.
* keymap.c (Fdescribe_buffer_bindings): Use SBYTES, not SCHARS,
when counting bytes.
* lisp.h (xlispstrdupa): Remove, replacing with ...
(SAFE_ALLOCA_STRING): ... new macro with different API.
This fixes a portability problem, namely, alloca result
passed to another function. All uses changed.
(SAFE_ALLOCA, SAFE_ALLOCA_LISP): Check for MAX_ALLOCA,
not MAX_ALLOCA - 1.
* regex.c (REGEX_USE_SAFE_ALLOCA, REGEX_SAFE_FREE)
(REGEX_ALLOCATE): New macros.
(REGEX_REALLOCATE, REGEX_ALLOCATE_STACK, REGEX_REALLOCATE_STACK)
(REGEX_FREE_STACK, FREE_VARIABLES, re_match_2_internal):
Use them.
* xdisp.c (message3): Use SAFE_ALLOCA_STRING rather than doing it
by hand.
(decode_mode_spec_coding): Store directly into buf rather than
into an alloca temporary and copying the temporary to the buf.
Fixes: debbugs:18410
Diffstat (limited to 'src/callproc.c')
-rw-r--r-- | src/callproc.c | 53 |
1 files changed, 30 insertions, 23 deletions
diff --git a/src/callproc.c b/src/callproc.c index e8b61b9f01f..0636571b26c 100644 --- a/src/callproc.c +++ b/src/callproc.c @@ -466,7 +466,7 @@ call_process (ptrdiff_t nargs, Lisp_Object *args, int filefd, && SREF (path, 1) == ':') path = Fsubstring (path, make_number (2), Qnil); - new_argv = SAFE_ALLOCA ((nargs > 4 ? nargs - 2 : 2) * sizeof *new_argv); + SAFE_NALLOCA (new_argv, 1, nargs < 4 ? 2 : nargs - 2); { struct gcpro gcpro1, gcpro2, gcpro3, gcpro4; @@ -1151,6 +1151,25 @@ add_env (char **env, char **new_env, char *string) return new_env; } +#ifndef DOS_NT + +/* 'exec' failed inside a child running NAME, with error number ERR. + Report the error and exit the child. */ + +static _Noreturn void +exec_failed (char const *name, int err) +{ + /* Avoid deadlock if the child's perror writes to a full pipe; the + pipe's reader is the parent, but with vfork the parent can't + run until the child exits. Truncate the diagnostic instead. */ + fcntl (STDERR_FILENO, F_SETFL, O_NONBLOCK); + + errno = err; + emacs_perror (name); + _exit (err == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE); +} +#endif + /* This is the last thing run in a newly forked inferior either synchronous or asynchronous. Copy descriptors IN, OUT and ERR as descriptors 0, 1 and 2. @@ -1174,8 +1193,6 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp, int cpid; HANDLE handles[3]; #else - int exec_errno; - pid_t pid = getpid (); #endif /* WINDOWSNT */ @@ -1196,6 +1213,8 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp, on that. */ pwd_var = xmalloc (i + 5); #else + if (MAX_ALLOCA - 5 < i) + exec_failed (new_argv[0], ENOMEM); pwd_var = alloca (i + 5); #endif temp = pwd_var + 4; @@ -1262,6 +1281,8 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp, } /* new_length + 2 to include PWD and terminating 0. */ + if (MAX_ALLOCA / sizeof *env - 2 < new_length) + exec_failed (new_argv[0], ENOMEM); env = new_env = alloca ((new_length + 2) * sizeof *env); /* If we have a PWD envvar, pass one down, but with corrected value. */ @@ -1270,6 +1291,8 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp, if (STRINGP (display)) { + if (MAX_ALLOCA - sizeof "DISPLAY=" < SBYTES (display)) + exec_failed (new_argv[0], ENOMEM); char *vdata = alloca (sizeof "DISPLAY=" + SBYTES (display)); strcpy (vdata, "DISPLAY="); strcat (vdata, SSDATA (display)); @@ -1345,16 +1368,7 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp, tcsetpgrp (0, pid); execve (new_argv[0], new_argv, env); - exec_errno = errno; - - /* Avoid deadlock if the child's perror writes to a full pipe; the - pipe's reader is the parent, but with vfork the parent can't - run until the child exits. Truncate the diagnostic instead. */ - fcntl (STDERR_FILENO, F_SETFL, O_NONBLOCK); - - errno = exec_errno; - emacs_perror (new_argv[0]); - _exit (exec_errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE); + exec_failed (new_argv[0], errno); #else /* MSDOS */ pid = run_msdos_command (new_argv, pwd_var + 4, in, out, err, env); @@ -1543,20 +1557,13 @@ init_callproc_1 (void) void init_callproc (void) { - char *data_dir = egetenv ("EMACSDATA"); + bool data_dir = egetenv ("EMACSDATA") != 0; - register char * sh; + char *sh; Lisp_Object tempdir; #ifdef HAVE_NS if (data_dir == 0) - { - const char *etc_dir = ns_etc_directory (); - if (etc_dir) - { - data_dir = alloca (strlen (etc_dir) + 1); - strcpy (data_dir, etc_dir); - } - } + data_dir == ns_etc_directory () != 0; #endif if (!NILP (Vinstallation_directory)) |