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From da2a27ef056a0179cbd80f9146e58b89403d9933 Mon Sep 17 00:00:00 2001
From: DRC <information@libjpeg-turbo.org>
Date: Sat, 18 Mar 2017 16:15:14 -0500
Subject: [PATCH] Honor max_memory_to_use/JPEGMEM/-maxmemory
This re-introduces a feature of the obsolete system-specific libjpeg
memory managers-- namely the ability to limit the amount of main memory
used by the library during decompression or multi-pass compression.
This is mainly beneficial for two reasons:
- Works around a 2 GB limit in libFuzzer
- Allows security-sensitive applications to set a memory limit for the
JPEG decoder so as to work around the progressive JPEG exploit
(LJT-01-004) described here:
http://www.libjpeg-turbo.org/pmwiki/uploads/About/TwoIssueswiththeJPEGStandard.pdf
This commit also removes obsolete documentation regarding the MS-DOS
memory manager (which itself was removed long ago) and changes the
documentation of the -maxmemory switch and JPEGMEM environment variable
to reflect the fact that backing stores are never used in libjpeg-turbo.
Inspired by:
https://github.com/caolanm/libjpeg-turbo/commit/066fee2e7d6834f24838bc1896aa38ca77209e3c
Closes #143
---
ChangeLog.md | 15 +++++++++++++++
cjpeg.1 | 4 ++--
djpeg.1 | 4 ++--
jmemnobs.c | 16 +++++++++++-----
jpegtran.1 | 4 ++--
libjpeg.txt | 14 ++++++--------
structure.txt | 24 +++++++++++-------------
usage.txt | 35 +++++------------------------------
8 files changed, 54 insertions(+), 62 deletions(-)
diff --git a/jmemnobs.c b/jmemnobs.c
index 5797198..ac12afa 100644
--- a/jmemnobs.c
+++ b/jmemnobs.c
@@ -3,8 +3,8 @@
*
* This file was part of the Independent JPEG Group's software:
* Copyright (C) 1992-1996, Thomas G. Lane.
- * It was modified by The libjpeg-turbo Project to include only code and
- * information relevant to libjpeg-turbo.
+ * libjpeg-turbo Modifications:
+ * Copyright (C) 2017, D. R. Commander.
* For conditions of distribution and use, see the accompanying README.ijg
* file.
*
@@ -15,7 +15,6 @@
* This is very portable in the sense that it'll compile on almost anything,
* but you'd better have lots of main memory (or virtual memory) if you want
* to process big images.
- * Note that the max_memory_to_use option is ignored by this implementation.
*/
#define JPEG_INTERNALS
@@ -66,14 +65,21 @@ jpeg_free_large (j_common_ptr cinfo, void *object, size_t sizeofobject)
/*
* This routine computes the total memory space available for allocation.
- * Here we always say, "we got all you want bud!"
*/
GLOBAL(size_t)
jpeg_mem_available (j_common_ptr cinfo, size_t min_bytes_needed,
size_t max_bytes_needed, size_t already_allocated)
{
- return max_bytes_needed;
+ if (cinfo->mem->max_memory_to_use) {
+ if (cinfo->mem->max_memory_to_use > already_allocated)
+ return cinfo->mem->max_memory_to_use - already_allocated;
+ else
+ return 0;
+ } else {
+ /* Here we always say, "we got all you want bud!" */
+ return max_bytes_needed;
+ }
}
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