[dunfell 04/11] xz: fix CVE-2022-1271


Steve Sakoman
 

From: Ralph Siemsen <ralph.siemsen@...>

Malicious filenames can make xzgrep to write to arbitrary files
or (with a GNU sed extension) lead to arbitrary code execution.

Upstream-Status: Backport [https://tukaani.org/xz/xzgrep-ZDI-CAN-16587.patch]
CVE: CVE-2022-1271

Signed-off-by: Ralph Siemsen <ralph.siemsen@...>
Signed-off-by: Steve Sakoman <steve@...>
---
.../xz/xz/CVE-2022-1271.patch | 96 +++++++++++++++++++
meta/recipes-extended/xz/xz_5.2.4.bb | 4 +-
2 files changed, 99 insertions(+), 1 deletion(-)
create mode 100644 meta/recipes-extended/xz/xz/CVE-2022-1271.patch

diff --git a/meta/recipes-extended/xz/xz/CVE-2022-1271.patch b/meta/recipes-extended/xz/xz/CVE-2022-1271.patch
new file mode 100644
index 0000000000..7841a534d3
--- /dev/null
+++ b/meta/recipes-extended/xz/xz/CVE-2022-1271.patch
@@ -0,0 +1,96 @@
+From 6bb2369742f9ff0451c245e8ca9b9dfac0cc88ba Mon Sep 17 00:00:00 2001
+From: Lasse Collin <lasse.collin@...>
+Date: Tue, 29 Mar 2022 19:19:12 +0300
+Subject: [PATCH] xzgrep: Fix escaping of malicious filenames (ZDI-CAN-16587).
+
+Malicious filenames can make xzgrep to write to arbitrary files
+or (with a GNU sed extension) lead to arbitrary code execution.
+
+xzgrep from XZ Utils versions up to and including 5.2.5 are
+affected. 5.3.1alpha and 5.3.2alpha are affected as well.
+This patch works for all of them.
+
+This bug was inherited from gzip's zgrep. gzip 1.12 includes
+a fix for zgrep.
+
+The issue with the old sed script is that with multiple newlines,
+the N-command will read the second line of input, then the
+s-commands will be skipped because it's not the end of the
+file yet, then a new sed cycle starts and the pattern space
+is printed and emptied. So only the last line or two get escaped.
+
+One way to fix this would be to read all lines into the pattern
+space first. However, the included fix is even simpler: All lines
+except the last line get a backslash appended at the end. To ensure
+that shell command substitution doesn't eat a possible trailing
+newline, a colon is appended to the filename before escaping.
+The colon is later used to separate the filename from the grep
+output so it is fine to add it here instead of a few lines later.
+
+The old code also wasn't POSIX compliant as it used \n in the
+replacement section of the s-command. Using \<newline> is the
+POSIX compatible method.
+
+LC_ALL=C was added to the two critical sed commands. POSIX sed
+manual recommends it when using sed to manipulate pathnames
+because in other locales invalid multibyte sequences might
+cause issues with some sed implementations. In case of GNU sed,
+these particular sed scripts wouldn't have such problems but some
+other scripts could have, see:
+
+ info '(sed)Locale Considerations'
+
+This vulnerability was discovered by:
+cleemy desu wayo working with Trend Micro Zero Day Initiative
+
+Thanks to Jim Meyering and Paul Eggert discussing the different
+ways to fix this and for coordinating the patch release schedule
+with gzip.
+
+Upstream-Status: Backport [https://tukaani.org/xz/xzgrep-ZDI-CAN-16587.patch]
+CVE: CVE-2022-1271
+
+Signed-off-by: Ralph Siemsen <ralph.siemsen@...>
+---
+ src/scripts/xzgrep.in | 20 ++++++++++++--------
+ 1 file changed, 12 insertions(+), 8 deletions(-)
+
+diff --git a/src/scripts/xzgrep.in b/src/scripts/xzgrep.in
+index a1fd19c..da1e65b 100644
+--- a/src/scripts/xzgrep.in
++++ b/src/scripts/xzgrep.in
+@@ -178,22 +178,26 @@ for i; do
+ { test $# -eq 1 || test $no_filename -eq 1; }; then
+ eval "$grep"
+ else
++ # Append a colon so that the last character will never be a newline
++ # which would otherwise get lost in shell command substitution.
++ i="$i:"
++
++ # Escape & \ | and newlines only if such characters are present
++ # (speed optimization).
+ case $i in
+ (*'
+ '* | *'&'* | *'\'* | *'|'*)
+- i=$(printf '%s\n' "$i" |
+- sed '
+- $!N
+- $s/[&\|]/\\&/g
+- $s/\n/\\n/g
+- ');;
++ i=$(printf '%s\n' "$i" | LC_ALL=C sed 's/[&\|]/\\&/g; $!s/$/\\/');;
+ esac
+- sed_script="s|^|$i:|"
++
++ # $i already ends with a colon so don't add it here.
++ sed_script="s|^|$i|"
+
+ # Fail if grep or sed fails.
+ r=$(
+ exec 4>&1
+- (eval "$grep" 4>&-; echo $? >&4) 3>&- | sed "$sed_script" >&3 4>&-
++ (eval "$grep" 4>&-; echo $? >&4) 3>&- |
++ LC_ALL=C sed "$sed_script" >&3 4>&-
+ ) || r=2
+ exit $r
+ fi >&3 5>&-
diff --git a/meta/recipes-extended/xz/xz_5.2.4.bb b/meta/recipes-extended/xz/xz_5.2.4.bb
index 67a6cbd569..6d80a4f2e9 100644
--- a/meta/recipes-extended/xz/xz_5.2.4.bb
+++ b/meta/recipes-extended/xz/xz_5.2.4.bb
@@ -23,7 +23,9 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=97d554a32881fee0aa283d96e47cb24a \
file://lib/getopt.c;endline=23;md5=2069b0ee710572c03bb3114e4532cd84 \
"

-SRC_URI = "https://tukaani.org/xz/xz-${PV}.tar.gz"
+SRC_URI = "https://tukaani.org/xz/xz-${PV}.tar.gz \
+ file://CVE-2022-1271.patch \
+ "
SRC_URI[md5sum] = "5ace3264bdd00c65eeec2891346f65e6"
SRC_URI[sha256sum] = "b512f3b726d3b37b6dc4c8570e137b9311e7552e8ccbab4d39d47ce5f4177145"
UPSTREAM_CHECK_REGEX = "xz-(?P<pver>\d+(\.\d+)+)\.tar"
--
2.25.1

Join openembedded-core@lists.openembedded.org to automatically receive all group messages.