keymap.c

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Author : Ran Benita
Date : 2018-03-11 17:07:06
Hash : 917636b1
Message : xkbcomp: fix crash when parsing an xkb_geometry section xkb_geometry sections are ignored; previously the had done so by returning NULL for the section's XkbFile, however some sections of the code do not expect this. Instead, create an XkbFile for it, it will never be processes and discarded later. Caught with the afl fuzzer. Signed-off-by: Ran Benita <ran234@gmail.com>
src/xkbcomp/keymap.c
/*
 * Copyright © 2009 Dan Nicholson
 * Copyright © 2012 Intel Corporation
 * Copyright © 2012 Ran Benita <ran234@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Author: Dan Nicholson <dbn.lists@gmail.com>
 *         Daniel Stone <daniel@fooishbar.org>
 *         Ran Benita <ran234@gmail.com>
 */

#include "xkbcomp-priv.h"

static void
ComputeEffectiveMask(struct xkb_keymap *keymap, struct xkb_mods *mods)
{
    mods->mask = mod_mask_get_effective(keymap, mods->mods);
}

static void
UpdateActionMods(struct xkb_keymap *keymap, union xkb_action *act,
                 xkb_mod_mask_t modmap)
{
    switch (act->type) {
    case ACTION_TYPE_MOD_SET:
    case ACTION_TYPE_MOD_LATCH:
    case ACTION_TYPE_MOD_LOCK:
        if (act->mods.flags & ACTION_MODS_LOOKUP_MODMAP)
            act->mods.mods.mods = modmap;
        ComputeEffectiveMask(keymap, &act->mods.mods);
        break;
    default:
        break;
    }
}

static const struct xkb_sym_interpret default_interpret = {
    .sym = XKB_KEY_NoSymbol,
    .repeat = true,
    .match = MATCH_ANY_OR_NONE,
    .mods = 0,
    .virtual_mod = XKB_MOD_INVALID,
    .action = { .type = ACTION_TYPE_NONE },
};

/**
 * Find an interpretation which applies to this particular level, either by
 * finding an exact match for the symbol and modifier combination, or a
 * generic XKB_KEY_NoSymbol match.
 */
static const struct xkb_sym_interpret *
FindInterpForKey(struct xkb_keymap *keymap, const struct xkb_key *key,
                 xkb_layout_index_t group, xkb_level_index_t level)
{
    const xkb_keysym_t *syms;
    int num_syms;

    num_syms = xkb_keymap_key_get_syms_by_level(keymap, key->keycode, group,
                                                level, &syms);
    if (num_syms == 0)
        return NULL;

    /*
     * There may be multiple matchings interprets; we should always return
     * the most specific. Here we rely on compat.c to set up the
     * sym_interprets array from the most specific to the least specific,
     * such that when we find a match we return immediately.
     */
    for (unsigned i = 0; i < keymap->num_sym_interprets; i++) {
        const struct xkb_sym_interpret *interp = &keymap->sym_interprets[i];

        xkb_mod_mask_t mods;
        bool found = false;

        if ((num_syms > 1 || interp->sym != syms[0]) &&
            interp->sym != XKB_KEY_NoSymbol)
            continue;

        if (interp->level_one_only && level != 0)
            mods = 0;
        else
            mods = key->modmap;

        switch (interp->match) {
        case MATCH_NONE:
            found = !(interp->mods & mods);
            break;
        case MATCH_ANY_OR_NONE:
            found = (!mods || (interp->mods & mods));
            break;
        case MATCH_ANY:
            found = (interp->mods & mods);
            break;
        case MATCH_ALL:
            found = ((interp->mods & mods) == interp->mods);
            break;
        case MATCH_EXACTLY:
            found = (interp->mods == mods);
            break;
        }

        if (found)
            return interp;
    }

    return &default_interpret;
}

static bool
ApplyInterpsToKey(struct xkb_keymap *keymap, struct xkb_key *key)
{
    xkb_mod_mask_t vmodmap = 0;
    xkb_layout_index_t group;
    xkb_level_index_t level;

    /* If we've been told not to bind interps to this key, then don't. */
    if (key->explicit & EXPLICIT_INTERP)
        return true;

    for (group = 0; group < key->num_groups; group++) {
        for (level = 0; level < XkbKeyNumLevels(key, group); level++) {
            const struct xkb_sym_interpret *interp;

            interp = FindInterpForKey(keymap, key, group, level);
            if (!interp)
                continue;

            /* Infer default key behaviours from the base level. */
            if (group == 0 && level == 0)
                if (!(key->explicit & EXPLICIT_REPEAT) && interp->repeat)
                    key->repeats = true;

            if ((group == 0 && level == 0) || !interp->level_one_only)
                if (interp->virtual_mod != XKB_MOD_INVALID)
                    vmodmap |= (1u << interp->virtual_mod);

            if (interp->action.type != ACTION_TYPE_NONE)
                key->groups[group].levels[level].action = interp->action;
        }
    }

    if (!(key->explicit & EXPLICIT_VMODMAP))
        key->vmodmap = vmodmap;

    return true;
}

/**
 * This collects a bunch of disparate functions which was done in the server
 * at various points that really should've been done within xkbcomp.  Turns out
 * your actions and types are a lot more useful when any of your modifiers
 * other than Shift actually do something ...
 */
static bool
UpdateDerivedKeymapFields(struct xkb_keymap *keymap)
{
    struct xkb_key *key;
    struct xkb_mod *mod;
    struct xkb_led *led;
    unsigned int i, j;

    /* Find all the interprets for the key and bind them to actions,
     * which will also update the vmodmap. */
    xkb_keys_foreach(key, keymap)
        if (!ApplyInterpsToKey(keymap, key))
            return false;

    /* Update keymap->mods, the virtual -> real mod mapping. */
    xkb_keys_foreach(key, keymap)
        xkb_mods_enumerate(i, mod, &keymap->mods)
            if (key->vmodmap & (1u << i))
                mod->mapping |= key->modmap;

    /* Now update the level masks for all the types to reflect the vmods. */
    for (i = 0; i < keymap->num_types; i++) {
        ComputeEffectiveMask(keymap, &keymap->types[i].mods);

        for (j = 0; j < keymap->types[i].num_entries; j++) {
            ComputeEffectiveMask(keymap, &keymap->types[i].entries[j].mods);
            ComputeEffectiveMask(keymap, &keymap->types[i].entries[j].preserve);
        }
    }

    /* Update action modifiers. */
    xkb_keys_foreach(key, keymap)
        for (i = 0; i < key->num_groups; i++)
            for (j = 0; j < XkbKeyNumLevels(key, i); j++)
                UpdateActionMods(keymap, &key->groups[i].levels[j].action,
                                 key->modmap);

    /* Update vmod -> led maps. */
    xkb_leds_foreach(led, keymap)
        ComputeEffectiveMask(keymap, &led->mods);

    /* Find maximum number of groups out of all keys in the keymap. */
    xkb_keys_foreach(key, keymap)
        keymap->num_groups = MAX(keymap->num_groups, key->num_groups);

    return true;
}

typedef bool (*compile_file_fn)(XkbFile *file,
                                struct xkb_keymap *keymap,
                                enum merge_mode merge);

static const compile_file_fn compile_file_fns[LAST_KEYMAP_FILE_TYPE + 1] = {
    [FILE_TYPE_KEYCODES] = CompileKeycodes,
    [FILE_TYPE_TYPES] = CompileKeyTypes,
    [FILE_TYPE_COMPAT] = CompileCompatMap,
    [FILE_TYPE_SYMBOLS] = CompileSymbols,
};

bool
CompileKeymap(XkbFile *file, struct xkb_keymap *keymap, enum merge_mode merge)
{
    bool ok;
    XkbFile *files[LAST_KEYMAP_FILE_TYPE + 1] = { NULL };
    enum xkb_file_type type;
    struct xkb_context *ctx = keymap->ctx;

    /* Collect section files and check for duplicates. */
    for (file = (XkbFile *) file->defs; file;
         file = (XkbFile *) file->common.next) {
        if (file->file_type < FIRST_KEYMAP_FILE_TYPE ||
            file->file_type > LAST_KEYMAP_FILE_TYPE) {
            if (file->file_type == FILE_TYPE_GEOMETRY) {
                log_vrb(ctx, 1,
                        "Geometry sections are not supported; ignoring\n");
            } else {
                log_err(ctx, "Cannot define %s in a keymap file\n",
                        xkb_file_type_to_string(file->file_type));
            }
            continue;
        }

        if (files[file->file_type]) {
            log_err(ctx,
                    "More than one %s section in keymap file; "
                    "All sections after the first ignored\n",
                    xkb_file_type_to_string(file->file_type));
            continue;
        }

        files[file->file_type] = file;
    }

    /*
     * Check that all required section were provided.
     * Report everything before failing.
     */
    ok = true;
    for (type = FIRST_KEYMAP_FILE_TYPE;
         type <= LAST_KEYMAP_FILE_TYPE;
         type++) {
        if (files[type] == NULL) {
            log_err(ctx, "Required section %s missing from keymap\n",
                    xkb_file_type_to_string(type));
            ok = false;
        }
    }
    if (!ok)
        return false;

    /* Compile sections. */
    for (type = FIRST_KEYMAP_FILE_TYPE;
         type <= LAST_KEYMAP_FILE_TYPE;
         type++) {
        log_dbg(ctx, "Compiling %s \"%s\"\n",
                xkb_file_type_to_string(type), files[type]->name);

        ok = compile_file_fns[type](files[type], keymap, merge);
        if (!ok) {
            log_err(ctx, "Failed to compile %s\n",
                    xkb_file_type_to_string(type));
            return false;
        }
    }

    return UpdateDerivedKeymapFields(keymap);
}
kc3-lang/libxkbcommon/src/xkbcomp/keymap.c

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kc3-lang/libxkbcommon /src/xkbcomp/keymap.c
