aboutsummaryrefslogtreecommitdiffstats
path: root/meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072.patch
diff options
context:
space:
mode:
Diffstat (limited to 'meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072.patch')
-rw-r--r--meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072.patch316
1 files changed, 316 insertions, 0 deletions
diff --git a/meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072.patch b/meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072.patch
new file mode 100644
index 0000000000..29ec3bbeab
--- /dev/null
+++ b/meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072.patch
@@ -0,0 +1,316 @@
+CVE: CVE-2021-41072
+Upstream-Status: Backport [https://github.com/plougher/squashfs-tools/commit/e048580]
+
+Backport commit to fix CVE-2021-41072. And squash a follow-up fix for
+CVE-2021-41072 from upstream:
+https://github.com/plougher/squashfs-tools/commit/19fcc93
+
+Update context for version 4.4.
+
+Signed-off-by: Kai Kang <kai.kang@windriver.com>
+
+From e0485802ec72996c20026da320650d8362f555bd Mon Sep 17 00:00:00 2001
+From: Phillip Lougher <phillip@squashfs.org.uk>
+Date: Sun, 12 Sep 2021 23:50:06 +0100
+Subject: [PATCH] Unsquashfs: additional write outside destination directory
+ exploit fix
+
+An issue on github (https://github.com/plougher/squashfs-tools/issues/72)
+showed how some specially crafted Squashfs filesystems containing
+invalid file names (with '/' and '..') can cause Unsquashfs to write
+files outside of the destination directory.
+
+Since then it has been shown that specially crafted Squashfs filesystems
+that contain a symbolic link pointing outside of the destination directory,
+coupled with an identically named file within the same directory, can
+cause Unsquashfs to write files outside of the destination directory.
+
+Specifically the symbolic link produces a pathname pointing outside
+of the destination directory, which is then followed when writing the
+duplicate identically named file within the directory.
+
+This commit fixes this exploit by explictly checking for duplicate
+filenames within a directory. As directories in v2.1, v3.x, and v4.0
+filesystems are sorted, this is achieved by checking for consecutively
+identical filenames. Additionally directories are checked to
+ensure they are sorted, to avoid attempts to evade the duplicate
+check.
+
+Version 1.x and 2.0 filesystems (where the directories were unsorted)
+are sorted and then the above duplicate filename check is applied.
+
+Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
+---
+ squashfs-tools/Makefile | 6 +-
+ squashfs-tools/unsquash-1.c | 6 ++
+ squashfs-tools/unsquash-12.c | 110 +++++++++++++++++++++++++++++++++
+ squashfs-tools/unsquash-1234.c | 21 +++++++
+ squashfs-tools/unsquash-2.c | 16 +++++
+ squashfs-tools/unsquash-3.c | 6 ++
+ squashfs-tools/unsquash-4.c | 6 ++
+ squashfs-tools/unsquashfs.h | 4 ++
+ 8 files changed, 173 insertions(+), 2 deletions(-)
+ create mode 100644 squashfs-tools/unsquash-12.c
+
+diff --git a/squashfs-tools/Makefile b/squashfs-tools/Makefile
+index 7262a2e..1b544ed 100755
+--- a/squashfs-tools/Makefile
++++ b/squashfs-tools/Makefile
+@@ -156,8 +156,8 @@ MKSQUASHFS_OBJS = mksquashfs.o read_fs.o
+ caches-queues-lists.o
+
+ UNSQUASHFS_OBJS = unsquashfs.o unsquash-1.o unsquash-2.o unsquash-3.o \
+- unsquash-4.o unsquash-123.o unsquash-34.o unsquash-1234.o swap.o \
+- compressor.o unsquashfs_info.o
++ unsquash-4.o unsquash-123.o unsquash-34.o unsquash-1234.o unsquash-12.o \
++ swap.o compressor.o unsquashfs_info.o
+
+ CFLAGS ?= -O2
+ CFLAGS += $(EXTRA_CFLAGS) $(INCLUDEDIR) -D_FILE_OFFSET_BITS=64 \
+@@ -353,6 +353,8 @@ unsquash-34.o: unsquashfs.h unsquash-34.c unsquashfs_error.h
+
+ unsquash-1234.o: unsquash-1234.c
+
++unsquash-12.o: unsquash-12.c unsquashfs.h
++
+ unsquashfs_xattr.o: unsquashfs_xattr.c unsquashfs.h squashfs_fs.h xattr.h
+
+ unsquashfs_info.o: unsquashfs.h squashfs_fs.h
+--- a/squashfs-tools/unsquash-1.c
++++ b/squashfs-tools/unsquash-1.c
+@@ -314,6 +314,12 @@ static struct dir *squashfs_opendir(unsi
+ }
+ }
+
++ /* check directory for duplicate names. Need to sort directory first */
++ sort_directory(dir);
++ if(check_directory(dir) == FALSE) {
++ ERROR("File system corrupted: directory has duplicate names\n");
++ goto corrupted;
++ }
+ return dir;
+
+ corrupted:
+diff --git a/squashfs-tools/unsquash-12.c b/squashfs-tools/unsquash-12.c
+new file mode 100644
+index 0000000..61bf128
+--- /dev/null
++++ b/squashfs-tools/unsquash-12.c
+@@ -0,0 +1,110 @@
++/*
++ * Unsquash a squashfs filesystem. This is a highly compressed read only
++ * filesystem.
++ *
++ * Copyright (c) 2021
++ * Phillip Lougher <phillip@squashfs.org.uk>
++ *
++ * This program is free software; you can redistribute it and/or
++ * modify it under the terms of the GNU General Public License
++ * as published by the Free Software Foundation; either version 2,
++ * or (at your option) any later version.
++ *
++ * This program is distributed in the hope that it will be useful,
++ * but WITHOUT ANY WARRANTY; without even the implied warranty of
++ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
++ * GNU General Public License for more details.
++ *
++ * You should have received a copy of the GNU General Public License
++ * along with this program; if not, write to the Free Software
++ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
++ *
++ * unsquash-12.c
++ *
++ * Helper functions used by unsquash-1 and unsquash-2.
++ */
++
++#include "unsquashfs.h"
++
++/*
++ * Bottom up linked list merge sort.
++ *
++ */
++void sort_directory(struct dir *dir)
++{
++ struct dir_ent *cur, *l1, *l2, *next;
++ int len1, len2, stride = 1;
++
++ if(dir->dir_count < 2)
++ return;
++
++ /*
++ * We can consider our linked-list to be made up of stride length
++ * sublists. Eacn iteration around this loop merges adjacent
++ * stride length sublists into larger 2*stride sublists. We stop
++ * when stride becomes equal to the entire list.
++ *
++ * Initially stride = 1 (by definition a sublist of 1 is sorted), and
++ * these 1 element sublists are merged into 2 element sublists, which
++ * are then merged into 4 element sublists and so on.
++ */
++ do {
++ l2 = dir->dirs; /* head of current linked list */
++ cur = NULL; /* empty output list */
++
++ /*
++ * Iterate through the linked list, merging adjacent sublists.
++ * On each interation l2 points to the next sublist pair to be
++ * merged (if there's only one sublist left this is simply added
++ * to the output list)
++ */
++ while(l2) {
++ l1 = l2;
++ for(len1 = 0; l2 && len1 < stride; len1 ++, l2 = l2->next);
++ len2 = stride;
++
++ /*
++ * l1 points to first sublist.
++ * l2 points to second sublist.
++ * Merge them onto the output list
++ */
++ while(len1 && l2 && len2) {
++ if(strcmp(l1->name, l2->name) <= 0) {
++ next = l1;
++ l1 = l1->next;
++ len1 --;
++ } else {
++ next = l2;
++ l2 = l2->next;
++ len2 --;
++ }
++
++ if(cur) {
++ cur->next = next;
++ cur = next;
++ } else
++ dir->dirs = cur = next;
++ }
++ /*
++ * One sublist is now empty, copy the other one onto the
++ * output list
++ */
++ for(; len1; len1 --, l1 = l1->next) {
++ if(cur) {
++ cur->next = l1;
++ cur = l1;
++ } else
++ dir->dirs = cur = l1;
++ }
++ for(; l2 && len2; len2 --, l2 = l2->next) {
++ if(cur) {
++ cur->next = l2;
++ cur = l2;
++ } else
++ dir->dirs = cur = l2;
++ }
++ }
++ cur->next = NULL;
++ stride = stride << 1;
++ } while(stride < dir->dir_count);
++}
+diff --git a/squashfs-tools/unsquash-1234.c b/squashfs-tools/unsquash-1234.c
+index e389f8d..98a81ed 100644
+--- a/squashfs-tools/unsquash-1234.c
++++ b/squashfs-tools/unsquash-1234.c
+@@ -72,3 +72,24 @@ void squashfs_closedir(struct dir *dir)
+
+ free(dir);
+ }
++
++
++/*
++ * Check directory for duplicate names. As the directory should be sorted,
++ * duplicates will be consecutive. Obviously we also need to check if the
++ * directory has been deliberately unsorted, to evade this check.
++ */
++int check_directory(struct dir *dir)
++{
++ int i;
++ struct dir_ent *ent;
++
++ if(dir->dir_count < 2)
++ return TRUE;
++
++ for(ent = dir->dirs, i = 0; i < dir->dir_count - 1; ent = ent->next, i++)
++ if(strcmp(ent->name, ent->next->name) >= 0)
++ return FALSE;
++
++ return TRUE;
++}
+diff --git a/squashfs-tools/unsquash-2.c b/squashfs-tools/unsquash-2.c
+index 956f96f..0e36f7d 100644
+--- a/squashfs-tools/unsquash-2.c
++++ b/squashfs-tools/unsquash-2.c
+@@ -29,6 +29,7 @@ static squashfs_fragment_entry_2 *fragme
+ static unsigned int *uid_table, *guid_table;
+ static char *inode_table, *directory_table;
+ static squashfs_operations ops;
++static int needs_sorting = FALSE;
+
+ static void read_block_list(unsigned int *block_list, char *block_ptr, int blocks)
+ {
+@@ -415,6 +416,17 @@ static struct dir *squashfs_opendir(unsi
+ }
+ }
+
++ if(needs_sorting)
++ sort_directory(dir);
++
++ /* check directory for duplicate names and sorting */
++ if(check_directory(dir) == FALSE) {
++ if(needs_sorting)
++ ERROR("File system corrupted: directory has duplicate names\n");
++ else
++ ERROR("File system corrupted: directory has duplicate names or is unsorted\n");
++ goto corrupted;
++ }
+ return dir;
+
+ corrupted:
+--- a/squashfs-tools/unsquash-3.c
++++ b/squashfs-tools/unsquash-3.c
+@@ -442,6 +442,12 @@ static struct dir *squashfs_opendir(unsi
+ }
+ }
+
++ /* check directory for duplicate names and sorting */
++ if(check_directory(dir) == FALSE) {
++ ERROR("File system corrupted: directory has duplicate names or is unsorted\n");
++ goto corrupted;
++ }
++
+ return dir;
+
+ corrupted:
+diff --git a/squashfs-tools/unsquash-4.c b/squashfs-tools/unsquash-4.c
+index 694783d..c615bb8 100644
+--- a/squashfs-tools/unsquash-4.c
++++ b/squashfs-tools/unsquash-4.c
+@@ -378,6 +378,12 @@ static struct dir *squashfs_opendir(unsi
+ }
+ }
+
++ /* check directory for duplicate names and sorting */
++ if(check_directory(dir) == FALSE) {
++ ERROR("File system corrupted: directory has duplicate names or is unsorted\n");
++ goto corrupted;
++ }
++
+ return dir;
+
+ corrupted:
+diff --git a/squashfs-tools/unsquashfs.h b/squashfs-tools/unsquashfs.h
+index f8cf78c..bf2a80d 100644
+--- a/squashfs-tools/unsquashfs.h
++++ b/squashfs-tools/unsquashfs.h
+@@ -266,4 +266,8 @@ extern long long *alloc_index_table(int)
+ /* unsquash-1234.c */
+ extern int check_name(char *, int);
+ extern void squashfs_closedir(struct dir *);
++extern int check_directory(struct dir *);
++
++/* unsquash-12.c */
++extern void sort_directory(struct dir *);
+ #endif
+--
+2.17.1
+