Skip to main content

Browse the archive

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
Raw File
shallow.h 
#ifndef SHALLOW_H
#define SHALLOW_H

#include "lockfile.h"
#include "object.h"
#include "repository.h"
#include "strbuf.h"

void set_alternate_shallow_file(struct repository *r, const char *path, int override);
int register_shallow(struct repository *r, const struct object_id *oid);
int unregister_shallow(const struct object_id *oid);
int is_repository_shallow(struct repository *r);

/*
 * Lock for updating the $GIT_DIR/shallow file.
 *
 * Use `commit_shallow_file()` to commit an update, or
 * `rollback_shallow_file()` to roll it back. In either case, any
 * in-memory cached information about which commits are shallow will be
 * appropriately invalidated so that future operations reflect the new
 * state.
 */
struct shallow_lock {
	struct lock_file lock;
};
#define SHALLOW_LOCK_INIT { LOCK_INIT }

/* commit $GIT_DIR/shallow and reset stat-validity checks */
int commit_shallow_file(struct repository *r, struct shallow_lock *lk);
/* rollback $GIT_DIR/shallow and reset stat-validity checks */
void rollback_shallow_file(struct repository *r, struct shallow_lock *lk);

struct commit_list *get_shallow_commits(struct object_array *heads,
					int depth, int shallow_flag, int not_shallow_flag);
struct commit_list *get_shallow_commits_by_rev_list(
		int ac, const char **av, int shallow_flag, int not_shallow_flag);
int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
			  const struct oid_array *extra);

void setup_alternate_shallow(struct shallow_lock *shallow_lock,
			     const char **alternate_shallow_file,
			     const struct oid_array *extra);

const char *setup_temporary_shallow(const struct oid_array *extra);

void advertise_shallow_grafts(int);

#define PRUNE_SHOW_ONLY 1
#define PRUNE_QUICK 2
void prune_shallow(unsigned options);

/*
 * Initialize with prepare_shallow_info() or zero-initialize (equivalent to
 * prepare_shallow_info with a NULL oid_array).
 */
struct shallow_info {
	struct oid_array *shallow;
	int *ours, nr_ours;
	int *theirs, nr_theirs;
	struct oid_array *ref;

	/* for receive-pack */
	uint32_t **used_shallow;
	int *need_reachability_test;
	int *reachable;
	int *shallow_ref;
	struct commit **commits;
	int nr_commits;
};

void prepare_shallow_info(struct shallow_info *, struct oid_array *);
void clear_shallow_info(struct shallow_info *);
void remove_nonexistent_theirs_shallow(struct shallow_info *);
void assign_shallow_commits_to_refs(struct shallow_info *info,
				    uint32_t **used,
				    int *ref_status);
int delayed_reachability_test(struct shallow_info *si, int c);

extern struct trace_key trace_shallow;

#endif /* SHALLOW_H */
back to top