Revision 447ac906e189535e77dcb1f4bbe3f1bc917d4c12 authored by Patrick Steinhardt on 01 December 2022, 14:45:31 UTC, committed by Junio C Hamano on 05 December 2022, 06:14:16 UTC
The `struct attr_stack` tracks the stack of all patterns together with their attributes. When parsing a gitattributes file that has more than 2^31 such patterns though we may trigger multiple out-of-bounds reads on 64 bit platforms. This is because while the `num_matches` variable is an unsigned integer, we always use a signed integer to iterate over them. I have not been able to reproduce this issue due to memory constraints on my systems. But despite the out-of-bounds reads, the worst thing that can seemingly happen is to call free(3P) with a garbage pointer when calling `attr_stack_free()`. Fix this bug by using unsigned integers to iterate over the array. While this makes the iteration somewhat awkward when iterating in reverse, it is at least better than knowingly running into an out-of-bounds read. While at it, convert the call to `ALLOC_GROW` to use `ALLOC_GROW_BY` instead. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 34ace8b
diffcore.h
/*
* Copyright (C) 2005 Junio C Hamano
*/
#ifndef DIFFCORE_H
#define DIFFCORE_H
#include "cache.h"
struct diff_options;
struct repository;
struct userdiff_driver;
/* This header file is internal between diff.c and its diff transformers
* (e.g. diffcore-rename, diffcore-pickaxe). Never include this header
* in anything else.
*/
/* We internally use unsigned short as the score value,
* and rely on an int capable to hold 32-bits. -B can take
* -Bmerge_score/break_score format and the two scores are
* passed around in one int (high 16-bit for merge and low 16-bit
* for break).
*/
#define MAX_SCORE 60000.0
#define DEFAULT_RENAME_SCORE 30000 /* rename/copy similarity minimum (50%) */
#define DEFAULT_BREAK_SCORE 30000 /* minimum for break to happen (50%) */
#define DEFAULT_MERGE_SCORE 36000 /* maximum for break-merge to happen (60%) */
#define MINIMUM_BREAK_SIZE 400 /* do not break a file smaller than this */
/**
* the internal representation for a single file (blob). It records the blob
* object name (if known -- for a work tree file it typically is a NUL SHA-1),
* filemode and pathname. This is what the `diff_addremove()`, `diff_change()`
* and `diff_unmerge()` synthesize and feed `diff_queue()` function with.
*/
struct diff_filespec {
struct object_id oid;
char *path;
void *data;
void *cnt_data;
unsigned long size;
int count; /* Reference count */
int rename_used; /* Count of rename users */
unsigned short mode; /* file mode */
unsigned oid_valid : 1; /* if true, use oid and trust mode;
* if false, use the name and read from
* the filesystem.
*/
#define DIFF_FILE_VALID(spec) (((spec)->mode) != 0)
unsigned should_free : 1; /* data should be free()'ed */
unsigned should_munmap : 1; /* data should be munmap()'ed */
unsigned dirty_submodule : 2; /* For submodules: its work tree is dirty */
#define DIRTY_SUBMODULE_UNTRACKED 1
#define DIRTY_SUBMODULE_MODIFIED 2
unsigned is_stdin : 1;
unsigned has_more_entries : 1; /* only appear in combined diff */
/* data should be considered "binary"; -1 means "don't know yet" */
signed int is_binary : 2;
struct userdiff_driver *driver;
};
struct diff_filespec *alloc_filespec(const char *);
void free_filespec(struct diff_filespec *);
void fill_filespec(struct diff_filespec *, const struct object_id *,
int, unsigned short);
/*
* Prefetch the entries in diff_queued_diff. The parameter is a pointer to a
* struct repository.
*/
void diff_queued_diff_prefetch(void *repository);
struct diff_populate_filespec_options {
unsigned check_size_only : 1;
unsigned check_binary : 1;
/*
* If an object is missing, diff_populate_filespec() will invoke this
* callback before attempting to read that object again.
*/
void (*missing_object_cb)(void *);
void *missing_object_data;
};
int diff_populate_filespec(struct repository *, struct diff_filespec *,
const struct diff_populate_filespec_options *);
void diff_free_filespec_data(struct diff_filespec *);
void diff_free_filespec_blob(struct diff_filespec *);
int diff_filespec_is_binary(struct repository *, struct diff_filespec *);
/**
* This records a pair of `struct diff_filespec`; the filespec for a file in
* the "old" set (i.e. preimage) is called `one`, and the filespec for a file
* in the "new" set (i.e. postimage) is called `two`. A change that represents
* file creation has NULL in `one`, and file deletion has NULL in `two`.
*
* A `filepair` starts pointing at `one` and `two` that are from the same
* filename, but `diffcore_std()` can break pairs and match component filespecs
* with other filespecs from a different filepair to form new filepair. This is
* called 'rename detection'.
*/
struct diff_filepair {
struct diff_filespec *one;
struct diff_filespec *two;
unsigned short int score;
char status; /* M C R A D U etc. (see Documentation/diff-format.txt or DIFF_STATUS_* in diff.h) */
unsigned broken_pair : 1;
unsigned renamed_pair : 1;
unsigned is_unmerged : 1;
unsigned done_skip_stat_unmatch : 1;
unsigned skip_stat_unmatch_result : 1;
};
#define DIFF_PAIR_UNMERGED(p) ((p)->is_unmerged)
#define DIFF_PAIR_RENAME(p) ((p)->renamed_pair)
#define DIFF_PAIR_BROKEN(p) \
( (!DIFF_FILE_VALID((p)->one) != !DIFF_FILE_VALID((p)->two)) && \
((p)->broken_pair != 0) )
#define DIFF_PAIR_TYPE_CHANGED(p) \
((S_IFMT & (p)->one->mode) != (S_IFMT & (p)->two->mode))
#define DIFF_PAIR_MODE_CHANGED(p) ((p)->one->mode != (p)->two->mode)
void diff_free_filepair(struct diff_filepair *);
int diff_unmodified_pair(struct diff_filepair *);
/**
* This is a collection of filepairs. Notable members are:
*
* - `queue`:
* An array of pointers to `struct diff_filepair`. This dynamically grows as
* you add filepairs;
*
* - `alloc`:
* The allocated size of the `queue` array;
*
* - `nr`:
* The number of elements in the `queue` array.
*/
struct diff_queue_struct {
struct diff_filepair **queue;
int alloc;
int nr;
};
#define DIFF_QUEUE_CLEAR(q) \
do { \
(q)->queue = NULL; \
(q)->nr = (q)->alloc = 0; \
} while (0)
extern struct diff_queue_struct diff_queued_diff;
struct diff_filepair *diff_queue(struct diff_queue_struct *,
struct diff_filespec *,
struct diff_filespec *);
void diff_q(struct diff_queue_struct *, struct diff_filepair *);
void diffcore_break(struct repository *, int);
void diffcore_rename(struct diff_options *);
void diffcore_merge_broken(void);
void diffcore_pickaxe(struct diff_options *);
void diffcore_order(const char *orderfile);
/* low-level interface to diffcore_order */
struct obj_order {
void *obj; /* setup by caller */
/* setup/used by order_objects() */
int orig_order;
int order;
};
typedef const char *(*obj_path_fn_t)(void *obj);
void order_objects(const char *orderfile, obj_path_fn_t obj_path,
struct obj_order *objs, int nr);
#define DIFF_DEBUG 0
#if DIFF_DEBUG
void diff_debug_filespec(struct diff_filespec *, int, const char *);
void diff_debug_filepair(const struct diff_filepair *, int);
void diff_debug_queue(const char *, struct diff_queue_struct *);
#else
#define diff_debug_filespec(a,b,c) do { /* nothing */ } while (0)
#define diff_debug_filepair(a,b) do { /* nothing */ } while (0)
#define diff_debug_queue(a,b) do { /* nothing */ } while (0)
#endif
int diffcore_count_changes(struct repository *r,
struct diff_filespec *src,
struct diff_filespec *dst,
void **src_count_p,
void **dst_count_p,
unsigned long *src_copied,
unsigned long *literal_added);
/*
* If filespec contains an OID and if that object is missing from the given
* repository, add that OID to to_fetch.
*/
void diff_add_if_missing(struct repository *r,
struct oid_array *to_fetch,
const struct diff_filespec *filespec);
#endif
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...