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
userdiff.h 
#ifndef USERDIFF_H
#define USERDIFF_H

#include "notes-cache.h"

struct index_state;
struct repository;

struct userdiff_funcname {
	const char *pattern;
	int cflags;
};

struct userdiff_driver {
	const char *name;
	const char *external;
	int binary;
	struct userdiff_funcname funcname;
	const char *word_regex;
	const char *textconv;
	struct notes_cache *textconv_cache;
	int textconv_want_cache;
};

int userdiff_config(const char *k, const char *v);
struct userdiff_driver *userdiff_find_by_name(const char *name);
struct userdiff_driver *userdiff_find_by_path(struct index_state *istate,
					      const char *path);

/*
 * Initialize any textconv-related fields in the driver and return it, or NULL
 * if it does not have textconv enabled at all.
 */
struct userdiff_driver *userdiff_get_textconv(struct repository *r,
					      struct userdiff_driver *driver);

#endif /* USERDIFF */
back to top