patch 9.0.2123: Problem with initializing the length of range() lists Commit: https://github.com/vim/vim/commit/df63da98d8dc284b1c76cfe1b17fa0acbd6094d8 Author: Christian Brabandt <cb@256bit.org> Date: Thu Nov 23 20:14:28 2023 +0100 patch 9.0.2123: Problem with initializing the length of range() lists Problem: Problem with initializing the length of range() lists Solution: Set length explicitly when it shouldn't contain any items range() may cause a wrong calculation of list length, which may later then cause a segfault in list_find(). This is usually not a problem, because range_list_materialize() calculates the length, when it materializes the list. In addition, in list_find() when the length of the range was wrongly initialized, it may seem to be valid, so the check for list index out-of-bounds will not be true, because it is called before the list is actually materialized. And so we may eventually try to access a null pointer, causing a segfault. So this patch does 3 things: - In f_range(), when we know that the list should be empty, explicitly set the list->lv_len value to zero. This should happen, when start is larger than end (in case the stride is positive) or end is larger than start when the stride is negative. This should fix the underlying issue properly. However, - as a safety measure, let's check that the requested index is not out of range one more time, after the list has been materialized and return NULL in case it suddenly is. - add a few more tests to verify the behaviour. fixes: #13557 closes: #13563 Co-authored-by: Tim Pope <tpope@github.com> Signed-off-by: Christian Brabandt <cb@256bit.org>

/* vi:set ts=8 sw=8 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.
 */


#ifndef NBDEBUG_H
#define NBDEBUG_H

#ifdef NBDEBUG

# ifndef ASSERT
#  define ASSERT(c) \
    if (!(c)) \
    { \
	fprintf(stderr, "Assertion failed: line %d, file %s\n", \
		__LINE__, __FILE__); \
	fflush(stderr); \
	abort(); \
    }
# endif

# define nbdebug(a) nbdbg a

# define NB_TRACE		0x00000001
# define NB_TRACE_VERBOSE	0x00000002
# define NB_TRACE_COLONCMD	0x00000004
# define NB_PRINT		0x00000008
# define NB_DEBUG_ALL		0xffffffff

# define NBDLEVEL(flags)	(nb_debug != NULL && (nb_dlevel & (flags)))

# define NBDEBUG_TRACE	1

typedef enum {
		WT_ENV = 1,		// look for env var if set
		WT_WAIT,		// look for ~/.gvimwait if set
		WT_STOP			// look for ~/.gvimstop if set
} WtWait;


void		 nbdbg(char *, ...) ATTRIBUTE_FORMAT_PRINTF(1, 2);

void nbdebug_wait(u_int wait_flags, char *wait_var, u_int wait_secs);
void nbdebug_log_init(char *log_var, char *level_var);

extern FILE	*nb_debug;
extern u_int	 nb_dlevel;		// nb_debug verbosity level

#else		// not NBDEBUG

# ifndef ASSERT
#  define ASSERT(c)
# endif

/*
 * The following 3 stubs are needed because a macro cannot be used because of
 * the variable number of arguments.
 */

void
nbdbg(
	char		*fmt,
	...)
{
}

#endif // NBDEBUG
#endif // NBDEBUG_H