[OE-core] [thud][PATCH 4/7] bzip2: fix CVE-2019-12900
Anuj Mittal
anuj.mittal at intel.com
Sun Jul 28 23:20:57 UTC 2019
Also include a patch to fix regression caused by it. See:
https://gitlab.com/federicomenaquintero/bzip2/issues/24
Signed-off-by: Anuj Mittal <anuj.mittal at intel.com>
---
.../bzip2/bzip2-1.0.6/CVE-2019-12900.patch | 33 +++++++++
.../fix-regression-CVE-2019-12900.patch | 82 ++++++++++++++++++++++
meta/recipes-extended/bzip2/bzip2_1.0.6.bb | 2 +
3 files changed, 117 insertions(+)
create mode 100644 meta/recipes-extended/bzip2/bzip2-1.0.6/CVE-2019-12900.patch
create mode 100644 meta/recipes-extended/bzip2/bzip2-1.0.6/fix-regression-CVE-2019-12900.patch
diff --git a/meta/recipes-extended/bzip2/bzip2-1.0.6/CVE-2019-12900.patch b/meta/recipes-extended/bzip2/bzip2-1.0.6/CVE-2019-12900.patch
new file mode 100644
index 0000000..9841644
--- /dev/null
+++ b/meta/recipes-extended/bzip2/bzip2-1.0.6/CVE-2019-12900.patch
@@ -0,0 +1,33 @@
+From 11e1fac27eb8a3076382200736874c78e09b75d6 Mon Sep 17 00:00:00 2001
+From: Albert Astals Cid <aacid at kde.org>
+Date: Tue, 28 May 2019 19:35:18 +0200
+Subject: [PATCH] Make sure nSelectors is not out of range
+
+nSelectors is used in a loop from 0 to nSelectors to access selectorMtf
+which is
+ UChar selectorMtf[BZ_MAX_SELECTORS];
+so if nSelectors is bigger than BZ_MAX_SELECTORS it'll do an invalid memory
+access
+
+Fixes out of bounds access discovered while fuzzying karchive
+CVE: CVE-2019-12900
+Upstream-Status: Backport
+Signed-off-by: Anuj Mittal <anuj.mittal at intel.com>
+
+---
+ decompress.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/decompress.c b/decompress.c
+index 311f566..b6e0a29 100644
+--- a/decompress.c
++++ b/decompress.c
+@@ -287,7 +287,7 @@ Int32 BZ2_decompress ( DState* s )
+ GET_BITS(BZ_X_SELECTOR_1, nGroups, 3);
+ if (nGroups < 2 || nGroups > 6) RETURN(BZ_DATA_ERROR);
+ GET_BITS(BZ_X_SELECTOR_2, nSelectors, 15);
+- if (nSelectors < 1) RETURN(BZ_DATA_ERROR);
++ if (nSelectors < 1 || nSelectors > BZ_MAX_SELECTORS) RETURN(BZ_DATA_ERROR);
+ for (i = 0; i < nSelectors; i++) {
+ j = 0;
+ while (True) {
diff --git a/meta/recipes-extended/bzip2/bzip2-1.0.6/fix-regression-CVE-2019-12900.patch b/meta/recipes-extended/bzip2/bzip2-1.0.6/fix-regression-CVE-2019-12900.patch
new file mode 100644
index 0000000..362e6cf
--- /dev/null
+++ b/meta/recipes-extended/bzip2/bzip2-1.0.6/fix-regression-CVE-2019-12900.patch
@@ -0,0 +1,82 @@
+From 212f3ed7ac3931c9e0e9167a0bdc16eeb3c76af4 Mon Sep 17 00:00:00 2001
+From: Mark Wielaard <mark at klomp.org>
+Date: Wed, 3 Jul 2019 01:28:11 +0200
+Subject: [PATCH] Accept as many selectors as the file format allows.
+
+But ignore any larger than the theoretical maximum, BZ_MAX_SELECTORS.
+
+The theoretical maximum number of selectors depends on the maximum
+blocksize (900000 bytes) and the number of symbols (50) that can be
+encoded with a different Huffman tree. BZ_MAX_SELECTORS is 18002.
+
+But the bzip2 file format allows the number of selectors to be encoded
+with 15 bits (because 18002 isn't a factor of 2 and doesn't fit in
+14 bits). So the file format maximum is 32767 selectors.
+
+Some bzip2 encoders might actually have written out more selectors
+than the theoretical maximum because they rounded up the number of
+selectors to some convenient factor of 8.
+
+The extra 14766 selectors can never be validly used by the decompression
+algorithm. So we can read them, but then discard them.
+
+This is effectively what was done (by accident) before we added a
+check for nSelectors to be at most BZ_MAX_SELECTORS to mitigate
+CVE-2019-12900.
+
+The extra selectors were written out after the array inside the
+EState struct. But the struct has extra space allocated after the
+selector arrays of 18060 bytes (which is larger than 14766).
+All of which will be initialized later (so the overwrite of that
+space with extra selector values would have been harmless).
+
+Upstream-Status: Backport
+Signed-off-by: Anuj Mittal <anuj.mittal at intel.com>
+
+---
+ compress.c | 2 +-
+ decompress.c | 10 ++++++++--
+ 2 files changed, 9 insertions(+), 3 deletions(-)
+
+diff --git a/compress.c b/compress.c
+index caf7696..19b662b 100644
+--- a/compress.c
++++ b/compress.c
+@@ -454,7 +454,7 @@ void sendMTFValues ( EState* s )
+
+ AssertH( nGroups < 8, 3002 );
+ AssertH( nSelectors < 32768 &&
+- nSelectors <= (2 + (900000 / BZ_G_SIZE)),
++ nSelectors <= BZ_MAX_SELECTORS,
+ 3003 );
+
+
+diff --git a/decompress.c b/decompress.c
+index b6e0a29..78060c9 100644
+--- a/decompress.c
++++ b/decompress.c
+@@ -287,7 +287,7 @@ Int32 BZ2_decompress ( DState* s )
+ GET_BITS(BZ_X_SELECTOR_1, nGroups, 3);
+ if (nGroups < 2 || nGroups > 6) RETURN(BZ_DATA_ERROR);
+ GET_BITS(BZ_X_SELECTOR_2, nSelectors, 15);
+- if (nSelectors < 1 || nSelectors > BZ_MAX_SELECTORS) RETURN(BZ_DATA_ERROR);
++ if (nSelectors < 1) RETURN(BZ_DATA_ERROR);
+ for (i = 0; i < nSelectors; i++) {
+ j = 0;
+ while (True) {
+@@ -296,8 +296,14 @@ Int32 BZ2_decompress ( DState* s )
+ j++;
+ if (j >= nGroups) RETURN(BZ_DATA_ERROR);
+ }
+- s->selectorMtf[i] = j;
++ /* Having more than BZ_MAX_SELECTORS doesn't make much sense
++ since they will never be used, but some implementations might
++ "round up" the number of selectors, so just ignore those. */
++ if (i < BZ_MAX_SELECTORS)
++ s->selectorMtf[i] = j;
+ }
++ if (nSelectors > BZ_MAX_SELECTORS)
++ nSelectors = BZ_MAX_SELECTORS;
+
+ /*--- Undo the MTF values for the selectors. ---*/
+ {
diff --git a/meta/recipes-extended/bzip2/bzip2_1.0.6.bb b/meta/recipes-extended/bzip2/bzip2_1.0.6.bb
index 025f45c..33cb8dd 100644
--- a/meta/recipes-extended/bzip2/bzip2_1.0.6.bb
+++ b/meta/recipes-extended/bzip2/bzip2_1.0.6.bb
@@ -14,6 +14,8 @@ SRC_URI = "http://downloads.yoctoproject.org/mirror/sources/${BP}.tar.gz \
file://Makefile.am;subdir=${BP} \
file://run-ptest \
file://CVE-2016-3189.patch \
+ file://CVE-2019-12900.patch \
+ file://fix-regression-CVE-2019-12900.patch \
"
SRC_URI[md5sum] = "00b516f4704d4a7cb50a1d97e6e8e15b"
--
2.7.4
More information about the Openembedded-core
mailing list