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>

/* blob.c */
blob_T *blob_alloc(void);
int rettv_blob_alloc(typval_T *rettv);
void rettv_blob_set(typval_T *rettv, blob_T *b);
int blob_copy(blob_T *from, typval_T *to);
void blob_free(blob_T *b);
void blob_unref(blob_T *b);
long blob_len(blob_T *b);
int blob_get(blob_T *b, int idx);
void blob_set(blob_T *blob, int idx, int byte);
void blob_set_append(blob_T *blob, int idx, int byte);
int blob_equal(blob_T *b1, blob_T *b2);
int read_blob(FILE *fd, typval_T *rettv, off_T offset, off_T size_arg);
int write_blob(FILE *fd, blob_T *blob);
char_u *blob2string(blob_T *blob, char_u **tofree, char_u *numbuf);
blob_T *string2blob(char_u *str);
int blob_slice_or_index(blob_T *blob, int is_range, varnumber_T n1, varnumber_T n2, int exclusive, typval_T *rettv);
int check_blob_index(long bloblen, varnumber_T n1, int quiet);
int check_blob_range(long bloblen, varnumber_T n1, varnumber_T n2, int quiet);
int blob_set_range(blob_T *dest, long n1, long n2, typval_T *src);
void blob_add(typval_T *argvars, typval_T *rettv);
void blob_remove(typval_T *argvars, typval_T *rettv, char_u *arg_errmsg);
void blob_filter_map(blob_T *blob_arg, filtermap_T filtermap, typval_T *expr, char_u *arg_errmsg, typval_T *rettv);
void blob_insert_func(typval_T *argvars, typval_T *rettv);
void blob_reduce(typval_T *argvars, typval_T *expr, typval_T *rettv);
void blob_reverse(blob_T *b, typval_T *rettv);
void f_blob2list(typval_T *argvars, typval_T *rettv);
void f_list2blob(typval_T *argvars, typval_T *rettv);
/* vim: set ft=c : */