From 9266d14b5ca4e29b970fa03272318e5f99386e06 Mon Sep 17 00:00:00 2001 From: Marcus Meissner Date: Thu, 5 Nov 2020 09:50:08 +0100 Subject: [PATCH] fixed a incorrect overflow check that could be optimized away. inspired by: https://android.googlesource.com/platform/external/libexif/+/8e7345f3bc0bad06ac369d6cbc1124c8ceaf7d4b https://source.android.com/security/bulletin/2020-11-01 CVE-2020-0452 --- NEWS | 3 ++- libexif/exif-entry.c | 4 ++-- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/libexif/exif-entry.c b/libexif/exif-entry.c index 3fc0ff9..4b866ce 100644 --- a/libexif/exif-entry.c +++ b/libexif/exif-entry.c @@ -1371,8 +1371,8 @@ exif_entry_get_value (ExifEntry *e, char *val, unsigned int maxlen) { unsigned char *utf16; - /* Sanity check the size to prevent overflow */ - if (e->size+sizeof(uint16_t)+1 < e->size) break; + /* Sanity check the size to prevent overflow. Note EXIF files are 64kb at most. */ + if (e->size >= 65536 - sizeof(uint16_t)*2) break; /* The tag may not be U+0000-terminated , so make a local U+0000-terminated copy before converting it */