Re: [Buildroot] [PATCH 1/1] package/qpdf: fix CVE-2021-36978

[Arnout Vandecappelle <arnout@mind.be>]

On 05/08/2021 11:09, Fabrice Fontaine wrote:
> QPDF 9.x through 9.1.1 and 10.x through 10.0.4 has a heap-based buffer
> overflow in Pl_ASCII85Decoder::write (called from Pl_AES_PDF::flush and
> Pl_AES_PDF::finish) when a certain downstream write fails.
> 
> Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>

 Applied to master, thanks.

 Regards,
 Arnout

> ---
>  ...to-be-safe-if-downstream-write-fails.patch | 86 +++++++++++++++++++
>  package/qpdf/qpdf.mk                          |  3 +
>  2 files changed, 89 insertions(+)
>  create mode 100644 package/qpdf/0002-Fix-some-pipelines-to-be-safe-if-downstream-write-fails.patch
> 
> diff --git a/package/qpdf/0002-Fix-some-pipelines-to-be-safe-if-downstream-write-fails.patch b/package/qpdf/0002-Fix-some-pipelines-to-be-safe-if-downstream-write-fails.patch
> new file mode 100644
> index 0000000000..70017350f2
> --- /dev/null
> +++ b/package/qpdf/0002-Fix-some-pipelines-to-be-safe-if-downstream-write-fails.patch
> @@ -0,0 +1,86 @@
> +From dc92574c10f3e2516ec6445b88c5d584f40df4e5 Mon Sep 17 00:00:00 2001
> +From: Jay Berkenbilt <ejb@ql.org>
> +Date: Mon, 4 Jan 2021 11:55:28 -0500
> +Subject: [PATCH] Fix some pipelines to be safe if downstream write fails (fuzz
> + issue 28262)
> +
> +[Retrieved (and updated to remove updates on ChangeLog and fuzz) from:
> +https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5]
> +Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
> +---
> + ChangeLog                     |   6 ++++++
> + fuzz/qpdf_extra/28262.fuzz    | Bin 0 -> 40395 bytes
> + libqpdf/Pl_AES_PDF.cc         |   2 +-
> + libqpdf/Pl_ASCII85Decoder.cc  |   7 +++++--
> + libqpdf/Pl_ASCIIHexDecoder.cc |   6 ++++--
> + libqpdf/Pl_Count.cc           |   2 +-
> + 6 files changed, 17 insertions(+), 6 deletions(-)
> + create mode 100644 fuzz/qpdf_extra/28262.fuzz
> +
> +diff --git a/libqpdf/Pl_AES_PDF.cc b/libqpdf/Pl_AES_PDF.cc
> +index 18cf3a4d..2865f804 100644
> +--- a/libqpdf/Pl_AES_PDF.cc
> ++++ b/libqpdf/Pl_AES_PDF.cc
> +@@ -238,6 +238,6 @@ Pl_AES_PDF::flush(bool strip_padding)
> + 	    }
> + 	}
> +     }
> +-    getNext()->write(this->outbuf, bytes);
> +     this->offset = 0;
> ++    getNext()->write(this->outbuf, bytes);
> + }
> +diff --git a/libqpdf/Pl_ASCII85Decoder.cc b/libqpdf/Pl_ASCII85Decoder.cc
> +index b8df3e87..9d9f6704 100644
> +--- a/libqpdf/Pl_ASCII85Decoder.cc
> ++++ b/libqpdf/Pl_ASCII85Decoder.cc
> +@@ -119,10 +119,13 @@ Pl_ASCII85Decoder::flush()
> + 
> +     QTC::TC("libtests", "Pl_ASCII85Decoder partial flush",
> + 	    (this->pos == 5) ? 0 : 1);
> +-    getNext()->write(outbuf, this->pos - 1);
> +-
> ++    // Reset before calling getNext()->write in case that throws an
> ++    // exception.
> ++    auto t = this->pos - 1;
> +     this->pos = 0;
> +     memset(this->inbuf, 117, 5);
> ++
> ++    getNext()->write(outbuf, t);
> + }
> + 
> + void
> +diff --git a/libqpdf/Pl_ASCIIHexDecoder.cc b/libqpdf/Pl_ASCIIHexDecoder.cc
> +index f20a9769..7845268e 100644
> +--- a/libqpdf/Pl_ASCIIHexDecoder.cc
> ++++ b/libqpdf/Pl_ASCIIHexDecoder.cc
> +@@ -97,12 +97,14 @@ Pl_ASCIIHexDecoder::flush()
> + 
> +     QTC::TC("libtests", "Pl_ASCIIHexDecoder partial flush",
> + 	    (this->pos == 2) ? 0 : 1);
> +-    getNext()->write(&ch, 1);
> +-
> ++    // Reset before calling getNext()->write in case that throws an
> ++    // exception.
> +     this->pos = 0;
> +     this->inbuf[0] = '0';
> +     this->inbuf[1] = '0';
> +     this->inbuf[2] = '\0';
> ++
> ++    getNext()->write(&ch, 1);
> + }
> + 
> + void
> +diff --git a/libqpdf/Pl_Count.cc b/libqpdf/Pl_Count.cc
> +index 8077092a..c35619b8 100644
> +--- a/libqpdf/Pl_Count.cc
> ++++ b/libqpdf/Pl_Count.cc
> +@@ -27,8 +27,8 @@ Pl_Count::write(unsigned char* buf, size_t len)
> +     if (len)
> +     {
> + 	this->m->count += QIntC::to_offset(len);
> +-	getNext()->write(buf, len);
> + 	this->m->last_char = buf[len - 1];
> ++	getNext()->write(buf, len);
> +     }
> + }
> + 
> diff --git a/package/qpdf/qpdf.mk b/package/qpdf/qpdf.mk
> index ec3d3f89a3..c96bf6bf2e 100644
> --- a/package/qpdf/qpdf.mk
> +++ b/package/qpdf/qpdf.mk
> @@ -14,6 +14,9 @@ QPDF_DEPENDENCIES = host-pkgconf zlib jpeg
>  
>  QPDF_CONF_OPTS = --with-random=/dev/urandom
>  
> +# 0002-Fix-some-pipelines-to-be-safe-if-downstream-write-fails.patch
> +QPDF_IGNORE_CVES += CVE-2021-36978
> +
>  ifeq ($(BR2_PACKAGE_GNUTLS),y)
>  QPDF_CONF_OPTS += --enable-crypto-gnutls
>  QPDF_DEPENDENCIES += gnutls
> 
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