view src/beval.c @ 33664:06b59278bfcf v9.0.2070

patch 9.0.2070: [security] disallow setting env in restricted mode Commit: https://github.com/vim/vim/commit/6b89dd6a7257a1e2e9c7ea070b407bc4674a5118 Author: Christian Brabandt <cb@256bit.org> Date: Thu Oct 26 22:14:17 2023 +0200 patch 9.0.2070: [security] disallow setting env in restricted mode Problem: [security] disallow setting env in restricted mode Solution: Setting environment variables in restricted mode could potentially be used to execute shell commands. Disallow this. restricted mode: disable allow setting of environment variables Setting environment variables in restricted mode, may have some unwanted consequences. So, for example by setting $GCONV_PATH in restricted mode and then calling the iconv() function, one may be able to execute some unwanted payload, because the `iconv_open()` function internally uses the `$GCONV_PATH` variable to find its conversion data. So let's disable setting environment variables, even so this is no complete protection, since we are not clearing the existing environment. I tried a few ways but wasn't successful :( One could also argue to disable the iconv() function completely in restricted mode, but who knows what other API functions can be influenced by setting some other unrelated environment variables. So let's leave it as it is currently. closes: #13394 See: https://huntr.com/bounties/b0a2eda1-459c-4e36-98e6-0cc7d7faccfe/ Signed-off-by: Christian Brabandt <cb@256bit.org>
author Christian Brabandt <cb@256bit.org>
date Thu, 26 Oct 2023 22:30:03 +0200
parents 8fc442c731ca
children
line wrap: on
line source

/* vi:set ts=8 sts=4 sw=4 noet:
 *
 * VIM - Vi IMproved	by Bram Moolenaar
 *			Visual Workshop integration by Gordon Prieur
 *
 * Do ":help uganda"  in Vim to read copying and usage conditions.
 * Do ":help credits" in Vim to see a list of people who contributed.
 * See README.txt for an overview of the Vim source code.
 */

#include "vim.h"

#if defined(FEAT_BEVAL) || defined(FEAT_PROP_POPUP) || defined(PROTO)
/*
 * Find text under the mouse position "row" / "col".
 * If "getword" is TRUE the returned text in "*textp" is not the whole line but
 * the relevant word in allocated memory.
 * Return OK if found.
 * Return FAIL if not found, no text at the mouse position.
 */
    int
find_word_under_cursor(
	int	    mouserow,
	int	    mousecol,
	int	    getword,
	int	    flags,	// flags for find_ident_at_pos()
	win_T	    **winp,	// can be NULL
	linenr_T    *lnump,	// can be NULL
	char_u	    **textp,
	int	    *colp,	// column where mouse hovers, can be NULL
	int	    *startcolp) // column where text starts, can be NULL
{
    int		row = mouserow;
    int		col = mousecol;
    int		scol;
    win_T	*wp;
    char_u	*lbuf;
    linenr_T	lnum;

    *textp = NULL;
    wp = mouse_find_win(&row, &col, FAIL_POPUP);
    if (wp == NULL || row < 0 || row >= wp->w_height || col >= wp->w_width)
	return FAIL;

    // Found a window and the cursor is in the text.  Now find the line
    // number.
    if (mouse_comp_pos(wp, &row, &col, &lnum, NULL))
	return FAIL;		// position is below the last line

    // Not past end of the file.
    lbuf = ml_get_buf(wp->w_buffer, lnum, FALSE);
    if (col > win_linetabsize(wp, lnum, lbuf, (colnr_T)MAXCOL))
	return FAIL;		// past end of line

    // Not past end of line.
    if (getword)
    {
	// For Netbeans we get the relevant part of the line
	// instead of the whole line.
	int		len;
	pos_T	*spos = NULL, *epos = NULL;

	if (VIsual_active)
	{
	    if (LT_POS(VIsual, curwin->w_cursor))
	    {
		spos = &VIsual;
		epos = &curwin->w_cursor;
	    }
	    else
	    {
		spos = &curwin->w_cursor;
		epos = &VIsual;
	    }
	}

	col = vcol2col(wp, lnum, col, NULL);
	scol = col;

	if (VIsual_active
		&& wp->w_buffer == curwin->w_buffer
		&& (lnum == spos->lnum
		    ? col >= (int)spos->col
		    : lnum > spos->lnum)
		&& (lnum == epos->lnum
		    ? col <= (int)epos->col
		    : lnum < epos->lnum))
	{
	    // Visual mode and pointing to the line with the
	    // Visual selection: return selected text, with a
	    // maximum of one line.
	    if (spos->lnum != epos->lnum || spos->col == epos->col)
		return FAIL;

	    lbuf = ml_get_buf(curwin->w_buffer, VIsual.lnum, FALSE);
	    len = epos->col - spos->col;
	    if (*p_sel != 'e')
		len += mb_ptr2len(lbuf + epos->col);
	    lbuf = vim_strnsave(lbuf + spos->col, len);
	    lnum = spos->lnum;
	    col = spos->col;
	    scol = col;
	}
	else
	{
	    // Find the word under the cursor.
	    ++emsg_off;
	    len = find_ident_at_pos(wp, lnum, (colnr_T)col,
		    &lbuf, &scol, flags);
	    --emsg_off;
	    if (len == 0)
		return FAIL;
	    lbuf = vim_strnsave(lbuf, len);
	}
    }
    else
	scol = col;

    if (winp != NULL)
	*winp = wp;
    if (lnump != NULL)
	*lnump = lnum;
    *textp = lbuf;
    if (colp != NULL)
	*colp = col;
    if (startcolp != NULL)
	*startcolp = scol;

    return OK;
}
#endif

#if defined(FEAT_BEVAL) || defined(PROTO)

/*
 * Get the text and position to be evaluated for "beval".
 * If "getword" is TRUE the returned text is not the whole line but the
 * relevant word in allocated memory.
 * Returns OK or FAIL.
 */
    int
get_beval_info(
	BalloonEval	*beval,
	int		getword,
	win_T		**winp,
	linenr_T	*lnump,
	char_u		**textp,
	int		*colp)
{
    int		row = mouse_row;
    int		col = mouse_col;

# ifdef FEAT_BEVAL_GUI
    if (gui.in_use)
    {
	row = Y_2_ROW(beval->y);
	col = X_2_COL(beval->x);
    }
# endif
    if (find_word_under_cursor(row, col, getword,
		FIND_IDENT + FIND_STRING + FIND_EVAL,
		winp, lnump, textp, colp, NULL) == OK)
    {
# ifdef FEAT_VARTABS
	vim_free(beval->vts);
	beval->vts = tabstop_copy((*winp)->w_buffer->b_p_vts_array);
	if ((*winp)->w_buffer->b_p_vts_array != NULL && beval->vts == NULL)
	{
	    if (getword)
		vim_free(*textp);
	    return FAIL;
	}
# endif
	beval->ts = (*winp)->w_buffer->b_p_ts;
	return OK;
    }

    return FAIL;
}

/*
 * Show a balloon with "mesg" or "list".
 * Hide the balloon when both are NULL.
 */
    void
post_balloon(BalloonEval *beval UNUSED, char_u *mesg, list_T *list UNUSED)
{
# ifdef FEAT_BEVAL_TERM
#  ifdef FEAT_GUI
    if (!gui.in_use)
#  endif
	ui_post_balloon(mesg, list);
# endif
# ifdef FEAT_BEVAL_GUI
    if (gui.in_use)
	// GUI can't handle a list
	gui_mch_post_balloon(beval, mesg);
# endif
}

/*
 * Returns TRUE if the balloon eval has been enabled:
 * 'ballooneval' for the GUI and 'balloonevalterm' for the terminal.
 * Also checks if the screen isn't scrolled up.
 */
    int
can_use_beval(void)
{
    return (0
#ifdef FEAT_BEVAL_GUI
		|| (gui.in_use && p_beval)
#endif
#ifdef FEAT_BEVAL_TERM
		|| (
# ifdef FEAT_GUI
		    !gui.in_use &&
# endif
		    p_bevalterm)
#endif
	     ) && msg_scrolled == 0;
}

# ifdef FEAT_EVAL
/*
 * Evaluate the expression 'bexpr' and set the text in the balloon 'beval'.
 */
    static void
bexpr_eval(
	BalloonEval	*beval,
	char_u		*bexpr,
	win_T		*wp,
	linenr_T	lnum,
	int		col,
	char_u		*text)
{
    win_T	*cw;
    long	winnr = 0;
    buf_T	*save_curbuf;
    int		use_sandbox;
    static char_u  *result = NULL;
    size_t	len;

    sctx_T	save_sctx = current_sctx;

    // Convert window pointer to number.
    for (cw = firstwin; cw != wp; cw = cw->w_next)
	++winnr;

    set_vim_var_nr(VV_BEVAL_BUFNR, (long)wp->w_buffer->b_fnum);
    set_vim_var_nr(VV_BEVAL_WINNR, winnr);
    set_vim_var_nr(VV_BEVAL_WINID, wp->w_id);
    set_vim_var_nr(VV_BEVAL_LNUM, (long)lnum);
    set_vim_var_nr(VV_BEVAL_COL, (long)(col + 1));
    set_vim_var_string(VV_BEVAL_TEXT, text, -1);
    vim_free(text);

    /*
     * Temporarily change the curbuf, so that we can determine whether
     * the buffer-local balloonexpr option was set insecurely.
     */
    save_curbuf = curbuf;
    curbuf = wp->w_buffer;
    use_sandbox = was_set_insecurely((char_u *)"balloonexpr",
				    *curbuf->b_p_bexpr == NUL ? 0 : OPT_LOCAL);
    curbuf = save_curbuf;
    if (use_sandbox)
	++sandbox;
    ++textlock;

    if (bexpr == p_bexpr)
    {
	sctx_T *sp = get_option_sctx("balloonexpr");

	if (sp != NULL)
	    current_sctx = *sp;
    }
    else
	current_sctx = curbuf->b_p_script_ctx[BV_BEXPR];

    vim_free(result);
    result = eval_to_string(bexpr, TRUE, TRUE);

    // Remove one trailing newline, it is added when the result was a
    // list and it's hardly ever useful.  If the user really wants a
    // trailing newline he can add two and one remains.
    if (result != NULL)
    {
	len = STRLEN(result);
	if (len > 0 && result[len - 1] == NL)
	    result[len - 1] = NUL;
    }

    if (use_sandbox)
	--sandbox;
    --textlock;
    current_sctx = save_sctx;

    set_vim_var_string(VV_BEVAL_TEXT, NULL, -1);
    if (result != NULL && result[0] != NUL)
	post_balloon(beval, result, NULL);

    // The 'balloonexpr' evaluation may show something on the screen
    // that requires a screen update.
    if (must_redraw)
	redraw_after_callback(FALSE, FALSE);
}
# endif

/*
 * Common code, invoked when the mouse is resting for a moment.
 */
    void
general_beval_cb(BalloonEval *beval, int state UNUSED)
{
#ifdef FEAT_EVAL
    win_T	*wp;
    int		col;
    linenr_T	lnum;
    char_u	*text;
    char_u	*bexpr;
#endif
    static int	recursive = FALSE;

    // Don't do anything when 'ballooneval' is off, messages scrolled the
    // windows up or we have no beval area.
    if (!can_use_beval() || beval == NULL)
	return;

    // Don't do this recursively.  Happens when the expression evaluation
    // takes a long time and invokes something that checks for CTRL-C typed.
    if (recursive)
	return;
    recursive = TRUE;

#ifdef FEAT_EVAL
    if (get_beval_info(beval, TRUE, &wp, &lnum, &text, &col) == OK)
    {
	bexpr = (*wp->w_buffer->b_p_bexpr == NUL) ? p_bexpr
						    : wp->w_buffer->b_p_bexpr;
	if (*bexpr != NUL)
	{
	    bexpr_eval(beval, bexpr, wp, lnum, col, text);
	    recursive = FALSE;
	    return;
	}
    }
#endif
#ifdef FEAT_NETBEANS_INTG
    if (bevalServers & BEVAL_NETBEANS)
	netbeans_beval_cb(beval, state);
#endif

    recursive = FALSE;
}

#endif