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
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
kwset.h
#ifndef KWSET_H
#define KWSET_H

/* This file has been copied from commit e7ac713d^ in the GNU grep git
 * repository. A few small changes have been made to adapt the code to
 * Git.
 */

/* kwset.h - header declaring the keyword set library.
   Copyright (C) 1989, 1998, 2005 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, see <http://www.gnu.org/licenses/>. */

/* Written August 1989 by Mike Haertel.
   The author may be reached (Email) at the address mike@ai.mit.edu,
   or (US mail) as Mike Haertel c/o Free Software Foundation. */

struct kwsmatch
{
  int index;			/* Index number of matching keyword. */
  size_t offset[1];		/* Offset of each submatch. */
  size_t size[1];		/* Length of each submatch. */
};

struct kwset_t;
typedef struct kwset_t* kwset_t;

/* Return an opaque pointer to a newly allocated keyword set, or NULL
   if enough memory cannot be obtained.  The argument if non-NULL
   specifies a table of character translations to be applied to all
   pattern and search text. */
kwset_t kwsalloc(unsigned char const *);

/* Incrementally extend the keyword set to include the given string.
   Return NULL for success, or an error message.  Remember an index
   number for each keyword included in the set. */
const char *kwsincr(kwset_t, char const *, size_t);

/* When the keyword set has been completely built, prepare it for
   use.  Return NULL for success, or an error message. */
const char *kwsprep(kwset_t);

/* Search through the given buffer for a member of the keyword set.
   Return a pointer to the leftmost longest match found, or NULL if
   no match is found.  If foundlen is non-NULL, store the length of
   the matching substring in the integer it points to.  Similarly,
   if foundindex is non-NULL, store the index of the particular
   keyword found therein. */
size_t kwsexec(kwset_t, char const *, size_t, struct kwsmatch *);

/* Deallocate the given keyword set and all its associated storage. */
void kwsfree(kwset_t);

#endif /* KWSET_H */
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