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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 
attr: fix out-of-bounds read with unreasonable amount of patterns
 
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
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rerere.h 
#ifndef RERERE_H
#define RERERE_H

#include "string-list.h"

struct pathspec;
struct repository;

#define RERERE_AUTOUPDATE   01
#define RERERE_NOAUTOUPDATE 02
#define RERERE_READONLY     04

/*
 * Marks paths that have been hand-resolved and added to the
 * index. Set in the util field of such paths after calling
 * rerere_remaining.
 */
extern void *RERERE_RESOLVED;

struct rerere_dir;
struct rerere_id {
	struct rerere_dir *collection;
	int variant;
};

int setup_rerere(struct repository *,struct string_list *, int);
#ifndef NO_THE_REPOSITORY_COMPATIBILITY_MACROS
#define rerere(flags) repo_rerere(the_repository, flags)
#endif
int repo_rerere(struct repository *, int);
/*
 * Given the conflict ID and the name of a "file" used for replaying
 * the recorded resolution (e.g. "preimage", "postimage"), return the
 * path to that filesystem entity.  With "file" specified with NULL,
 * return the path to the directory that houses these files.
 */
const char *rerere_path(const struct rerere_id *, const char *file);
int rerere_forget(struct repository *, struct pathspec *);
int rerere_remaining(struct repository *, struct string_list *);
void rerere_clear(struct repository *, struct string_list *);
void rerere_gc(struct repository *, struct string_list *);

#define OPT_RERERE_AUTOUPDATE(v) OPT_UYN(0, "rerere-autoupdate", (v), \
	N_("update the index with reused conflict resolution if possible"))

#endif
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