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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
Raw File
notes-utils.h 
#ifndef NOTES_UTILS_H
#define NOTES_UTILS_H

#include "notes.h"

struct commit_list;
struct object_id;
struct repository;

/*
 * Create new notes commit from the given notes tree
 *
 * Properties of the created commit:
 * - tree: the result of converting t to a tree object with write_notes_tree().
 * - parents: the given parents OR (if NULL) the commit referenced by t->ref.
 * - author/committer: the default determined by commit_tree().
 * - commit message: msg
 *
 * The resulting commit SHA1 is stored in result_sha1.
 */
void create_notes_commit(struct repository *r,
			 struct notes_tree *t,
			 struct commit_list *parents,
			 const char *msg, size_t msg_len,
			 struct object_id *result_oid);

void commit_notes(struct repository *r, struct notes_tree *t, const char *msg);

enum notes_merge_strategy {
		NOTES_MERGE_RESOLVE_MANUAL = 0,
		NOTES_MERGE_RESOLVE_OURS,
		NOTES_MERGE_RESOLVE_THEIRS,
		NOTES_MERGE_RESOLVE_UNION,
		NOTES_MERGE_RESOLVE_CAT_SORT_UNIQ
};

struct notes_rewrite_cfg {
	struct notes_tree **trees;
	const char *cmd;
	int enabled;
	combine_notes_fn combine;
	struct string_list *refs;
	int refs_from_env;
	int mode_from_env;
};

int parse_notes_merge_strategy(const char *v, enum notes_merge_strategy *s);
struct notes_rewrite_cfg *init_copy_notes_for_rewrite(const char *cmd);
int copy_note_for_rewrite(struct notes_rewrite_cfg *c,
			  const struct object_id *from_obj, const struct object_id *to_obj);
void finish_copy_notes_for_rewrite(struct repository *r,
				   struct notes_rewrite_cfg *c,
				   const char *msg);

#endif
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