From 41bd04234b104312f54d25822f68738ba8d7133d Mon Sep 17 00:00:00 2001
From: Marcus Meissner <marcus@jet.franken.de>
Date: Tue, 25 Jul 2017 23:44:44 +0200
Subject: [PATCH] fixes some (not all) buffer overreads during decoding pentax
makernote entries.
This should fix:
https://sourceforge.net/p/libexif/bugs/125/ CVE-2016-6328
---
libexif/pentax/mnote-pentax-entry.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/libexif/pentax/mnote-pentax-entry.c b/libexif/pentax/mnote-pentax-entry.c
index d03d159..ea0429a 100644
--- a/libexif/pentax/mnote-pentax-entry.c
+++ b/libexif/pentax/mnote-pentax-entry.c
@@ -425,24 +425,34 @@ mnote_pentax_entry_get_value (MnotePentaxEntry *entry,
case EXIF_FORMAT_SHORT:
{
const unsigned char *data = entry->data;
- size_t k, len = strlen(val);
+ size_t k, len = strlen(val), sizeleft;
+
+ sizeleft = entry->size;
for(k=0; k<entry->components; k++) {
+ if (sizeleft < 2)
+ break;
vs = exif_get_short (data, entry->order);
snprintf (val+len, maxlen-len, "%i ", vs);
len = strlen(val);
data += 2;
+ sizeleft -= 2;
}
}
break;
case EXIF_FORMAT_LONG:
{
const unsigned char *data = entry->data;
- size_t k, len = strlen(val);
+ size_t k, len = strlen(val), sizeleft;
+
+ sizeleft = entry->size;
for(k=0; k<entry->components; k++) {
+ if (sizeleft < 4)
+ break;
vl = exif_get_long (data, entry->order);
snprintf (val+len, maxlen-len, "%li", (long int) vl);
len = strlen(val);
data += 4;
+ sizeleft -= 4;
}
}
break;
@@ -455,5 +465,5 @@ mnote_pentax_entry_get_value (MnotePentaxEntry *entry,
break;
}
- return (val);
+ return val;
}
