Subject: [bug#30416] [PATCH] gnu: libtasn1: Fix CVE-2018-6003.

From: Marius Bakke <[email-masked]>
Date: Sun, 11 Feb 2018 02:31:08 +0100

On February 10, 2018 10:54:44 PM GMT+01:00, Leo Famulari <[email-masked]> wrote:
>* gnu/packages/patches/libtasn1-CVE-2018-6003.patch: New file.
>* gnu/local.mk (dist_patch_DATA): Add it.
>* gnu/packages/tls.scm (libtasn1/fixed)[source]: Use it.

LGTM. I think we already ungrafted the fixed version on core-updates, so I guess we should merge and "re-graft" this new patch.

>---
> gnu/local.mk                                      |  1 +
>gnu/packages/patches/libtasn1-CVE-2018-6003.patch | 73
>+++++++++++++++++++++++
> gnu/packages/tls.scm                              |  3 +-
> 3 files changed, 76 insertions(+), 1 deletion(-)
> create mode 100644 gnu/packages/patches/libtasn1-CVE-2018-6003.patch
>
>diff --git a/gnu/local.mk b/gnu/local.mk
>index eb968dede..9b32e5880 100644
>--- a/gnu/local.mk
>+++ b/gnu/local.mk
>@@ -852,6 +852,7 @@ dist_patch_DATA =						\
>   %D%/packages/patches/libssh2-fix-build-failure-with-gcrypt.patch	\
>   %D%/packages/patches/libtar-CVE-2013-4420.patch 		\
>   %D%/packages/patches/libtasn1-CVE-2017-10790.patch		\
>+  %D%/packages/patches/libtasn1-CVE-2018-6003.patch		\
>   %D%/packages/patches/libtheora-config-guess.patch		\
>   %D%/packages/patches/libtiff-CVE-2016-10688.patch		\
>   %D%/packages/patches/libtiff-CVE-2017-9936.patch		\
>diff --git a/gnu/packages/patches/libtasn1-CVE-2018-6003.patch
>b/gnu/packages/patches/libtasn1-CVE-2018-6003.patch
>new file mode 100644
>index 000000000..3e6140518
>--- /dev/null
>+++ b/gnu/packages/patches/libtasn1-CVE-2018-6003.patch
>@@ -0,0 +1,73 @@
>+Fix CVE-2018-6003:
>+
>+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2018-6003
>+https://lists.gnu.org/archive/html/help-libtasn1/2018-01/msg00000.html
>+
>+Patch copied from upstream source repository:
>+
>+https://gitlab.com/gnutls/libtasn1/commit/c593ae84cfcde8fea45787e53950e0ac71e9ca97
>+
>+From c593ae84cfcde8fea45787e53950e0ac71e9ca97 Mon Sep 17 00:00:00 2001
>+From: Nikos Mavrogiannopoulos <[email-masked]>
>+Date: Thu, 4 Jan 2018 10:52:05 +0100
>+Subject: [PATCH] _asn1_decode_simple_ber: restrict the levels of
>recursion to 3
>+
>+On indefinite string decoding, setting a maximum level of recursions
>+protects the BER decoder from a stack exhaustion due to large amounts
>+of recursion.
>+
>+Signed-off-by: Nikos Mavrogiannopoulos <[email-masked]>
>+---
>+ lib/decoding.c | 21 +++++++++++++++++++--
>+ 1 file changed, 19 insertions(+), 2 deletions(-)
>+
>+diff --git a/lib/decoding.c b/lib/decoding.c
>+index 2240b09..0ee35d3 100644
>+--- a/lib/decoding.c
>++++ b/lib/decoding.c
>+@@ -45,6 +45,13 @@
>+ 
>+ #define DECODE_FLAG_HAVE_TAG 1
>+ #define DECODE_FLAG_INDEFINITE (1<<1)
>++/* On indefinite string decoding, allow this maximum levels
>++ * of recursion. Allowing infinite recursion, makes the BER
>++ * decoder susceptible to stack exhaustion due to that recursion.
>++ */
>++#define DECODE_FLAG_LEVEL1 (1<<2)
>++#define DECODE_FLAG_LEVEL2 (1<<3)
>++#define DECODE_FLAG_LEVEL3 (1<<4)
>+ 
>+ #define DECR_LEN(l, s) do { \
>+ 	  l -= s; \
>+@@ -2216,7 +2223,8 @@ _asn1_decode_simple_ber (unsigned int etype,
>const unsigned char *der,
>+     }
>+ 
>+   /* indefinite constructed */
>+-  if (((dflags & DECODE_FLAG_INDEFINITE) || class ==
>ASN1_CLASS_STRUCTURED) && ETYPE_IS_STRING(etype))
>++  if ((((dflags & DECODE_FLAG_INDEFINITE) || class ==
>ASN1_CLASS_STRUCTURED) && ETYPE_IS_STRING(etype)) &&
>++      !(dflags & DECODE_FLAG_LEVEL3))
>+     {
>+       len_len = 1;
>+ 
>+@@ -2236,8 +2244,17 @@ _asn1_decode_simple_ber (unsigned int etype,
>const unsigned char *der,
>+       do
>+         {
>+           unsigned tmp_len;
>++          unsigned flags = DECODE_FLAG_HAVE_TAG;
>++
>++          if (dflags & DECODE_FLAG_LEVEL1)
>++                flags |= DECODE_FLAG_LEVEL2;
>++          else if (dflags & DECODE_FLAG_LEVEL2)
>++		flags |= DECODE_FLAG_LEVEL3;
>++	  else
>++		flags |= DECODE_FLAG_LEVEL1;
>+ 
>+-          result = asn1_decode_simple_ber(etype, p, der_len, &out,
>&out_len, &tmp_len);
>++          result = _asn1_decode_simple_ber(etype, p, der_len, &out,
>&out_len, &tmp_len,
>++                                           flags);
>+           if (result != ASN1_SUCCESS)
>+             {
>+               warn();
>+--
>+libgit2 0.26.0
>+
>diff --git a/gnu/packages/tls.scm b/gnu/packages/tls.scm
>index fa58f90cb..c2123add4 100644
>--- a/gnu/packages/tls.scm
>+++ b/gnu/packages/tls.scm
>@@ -91,7 +91,8 @@ specifications.")
>     (inherit libtasn1)
>     (source (origin
>               (inherit (package-source libtasn1))
>-              (patches (search-patches
>"libtasn1-CVE-2017-10790.patch"))))))
>+              (patches (search-patches "libtasn1-CVE-2017-10790.patch"
>+                                      
>"libtasn1-CVE-2018-6003.patch"))))))
> 
> (define-public asn1c
>   (package

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