patches/xz-5.2.5.local.patch: merged from upstream to fix ZDI-CAN-16587.

1 files changed, 94 insertions, 0 deletions

diff --git a/patches/xz-5.2.5.local.patch b/patches/xz-5.2.5.local.patch
new file mode 100644
index 0000000..406ded5
--- /dev/null
+++ b/patches/xz-5.2.5.local.patch
@@ -0,0 +1,94 @@
+From 69d1b3fc29677af8ade8dc15dba83f0589cb63d6 Mon Sep 17 00:00:00 2001
+From: Lasse Collin <lasse.collin@tukaani.org>
+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.
+---
+ 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 b180936..e5186ba 100644
+--- a/src/scripts/xzgrep.in
++++ b/src/scripts/xzgrep.in
+@@ -180,22 +180,26 @@ 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>&-
+-- 
+2.35.1
+