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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
advice.h 
#ifndef ADVICE_H
#define ADVICE_H

#include "git-compat-util.h"

extern int advice_fetch_show_forced_updates;
extern int advice_push_update_rejected;
extern int advice_push_non_ff_current;
extern int advice_push_non_ff_matching;
extern int advice_push_already_exists;
extern int advice_push_fetch_first;
extern int advice_push_needs_force;
extern int advice_push_unqualified_ref_name;
extern int advice_push_ref_needs_update;
extern int advice_status_hints;
extern int advice_status_u_option;
extern int advice_status_ahead_behind_warning;
extern int advice_commit_before_merge;
extern int advice_reset_quiet_warning;
extern int advice_resolve_conflict;
extern int advice_sequencer_in_use;
extern int advice_implicit_identity;
extern int advice_detached_head;
extern int advice_set_upstream_failure;
extern int advice_object_name_warning;
extern int advice_amworkdir;
extern int advice_rm_hints;
extern int advice_add_embedded_repo;
extern int advice_ignored_hook;
extern int advice_waiting_for_editor;
extern int advice_graft_file_deprecated;
extern int advice_checkout_ambiguous_remote_branch_name;
extern int advice_submodule_alternate_error_strategy_die;
extern int advice_add_ignored_file;
extern int advice_add_empty_pathspec;

/*
 * To add a new advice, you need to:
 * Define a new advice_type.
 * Add a new entry to advice_setting array.
 * Add the new config variable to Documentation/config/advice.txt.
 * Call advise_if_enabled to print your advice.
 */
 enum advice_type {
	ADVICE_ADD_EMBEDDED_REPO,
	ADVICE_AM_WORK_DIR,
	ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME,
	ADVICE_COMMIT_BEFORE_MERGE,
	ADVICE_DETACHED_HEAD,
	ADVICE_FETCH_SHOW_FORCED_UPDATES,
	ADVICE_GRAFT_FILE_DEPRECATED,
	ADVICE_IGNORED_HOOK,
	ADVICE_IMPLICIT_IDENTITY,
	ADVICE_NESTED_TAG,
	ADVICE_OBJECT_NAME_WARNING,
	ADVICE_PUSH_ALREADY_EXISTS,
	ADVICE_PUSH_FETCH_FIRST,
	ADVICE_PUSH_NEEDS_FORCE,
	ADVICE_PUSH_NON_FF_CURRENT,
	ADVICE_PUSH_NON_FF_MATCHING,
	ADVICE_PUSH_UNQUALIFIED_REF_NAME,
	ADVICE_PUSH_UPDATE_REJECTED_ALIAS,
	ADVICE_PUSH_UPDATE_REJECTED,
	ADVICE_PUSH_REF_NEEDS_UPDATE,
	ADVICE_RESET_QUIET_WARNING,
	ADVICE_RESOLVE_CONFLICT,
	ADVICE_RM_HINTS,
	ADVICE_SEQUENCER_IN_USE,
	ADVICE_SET_UPSTREAM_FAILURE,
	ADVICE_STATUS_AHEAD_BEHIND_WARNING,
	ADVICE_STATUS_HINTS,
	ADVICE_STATUS_U_OPTION,
	ADVICE_SUBMODULE_ALTERNATE_ERROR_STRATEGY_DIE,
	ADVICE_WAITING_FOR_EDITOR,
};

int git_default_advice_config(const char *var, const char *value);
__attribute__((format (printf, 1, 2)))
void advise(const char *advice, ...);

/**
 * Checks if advice type is enabled (can be printed to the user).
 * Should be called before advise().
 */
int advice_enabled(enum advice_type type);

/**
 * Checks the visibility of the advice before printing.
 */
void advise_if_enabled(enum advice_type type, const char *advice, ...);

int error_resolve_conflict(const char *me);
void NORETURN die_resolve_conflict(const char *me);
void NORETURN die_conclude_merge(void);
void detach_advice(const char *new_name);

#endif /* ADVICE_H */
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