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-rw-r--r--meta/recipes-devtools/squashfs-tools/squashfs-tools/CVE-2021-41072.patch325
1 files changed, 325 insertions, 0 deletions
diff --git a/meta/recipes-devtools/squashfs-tools/squashfs-tools/CVE-2021-41072.patch b/meta/recipes-devtools/squashfs-tools/squashfs-tools/CVE-2021-41072.patch
new file mode 100644
index 0000000000..94d6da4b14
--- /dev/null
+++ b/meta/recipes-devtools/squashfs-tools/squashfs-tools/CVE-2021-41072.patch
@@ -0,0 +1,325 @@
1CVE: CVE-2021-41072
2Upstream-Status: Backport [https://github.com/plougher/squashfs-tools/commit/e048580]
3
4Signed-off-by: Kai Kang <kai.kang@windriver.com>
5
6From e0485802ec72996c20026da320650d8362f555bd Mon Sep 17 00:00:00 2001
7From: Phillip Lougher <phillip@squashfs.org.uk>
8Date: Sun, 12 Sep 2021 23:50:06 +0100
9Subject: [PATCH] Unsquashfs: additional write outside destination directory
10 exploit fix
11
12An issue on github (https://github.com/plougher/squashfs-tools/issues/72)
13showed how some specially crafted Squashfs filesystems containing
14invalid file names (with '/' and '..') can cause Unsquashfs to write
15files outside of the destination directory.
16
17Since then it has been shown that specially crafted Squashfs filesystems
18that contain a symbolic link pointing outside of the destination directory,
19coupled with an identically named file within the same directory, can
20cause Unsquashfs to write files outside of the destination directory.
21
22Specifically the symbolic link produces a pathname pointing outside
23of the destination directory, which is then followed when writing the
24duplicate identically named file within the directory.
25
26This commit fixes this exploit by explictly checking for duplicate
27filenames within a directory. As directories in v2.1, v3.x, and v4.0
28filesystems are sorted, this is achieved by checking for consecutively
29identical filenames. Additionally directories are checked to
30ensure they are sorted, to avoid attempts to evade the duplicate
31check.
32
33Version 1.x and 2.0 filesystems (where the directories were unsorted)
34are sorted and then the above duplicate filename check is applied.
35
36Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
37---
38 squashfs-tools/Makefile | 6 +-
39 squashfs-tools/unsquash-1.c | 6 ++
40 squashfs-tools/unsquash-12.c | 110 +++++++++++++++++++++++++++++++++
41 squashfs-tools/unsquash-1234.c | 21 +++++++
42 squashfs-tools/unsquash-2.c | 16 +++++
43 squashfs-tools/unsquash-3.c | 6 ++
44 squashfs-tools/unsquash-4.c | 6 ++
45 squashfs-tools/unsquashfs.h | 4 ++
46 8 files changed, 173 insertions(+), 2 deletions(-)
47 create mode 100644 squashfs-tools/unsquash-12.c
48
49diff --git a/squashfs-tools/Makefile b/squashfs-tools/Makefile
50index 7262a2e..1b544ed 100755
51--- a/squashfs-tools/Makefile
52+++ b/squashfs-tools/Makefile
53@@ -160,8 +160,8 @@ MKSQUASHFS_OBJS = mksquashfs.o read_fs.o action.o swap.o pseudo.o compressor.o \
54 caches-queues-lists.o reader.o tar.o
55
56 UNSQUASHFS_OBJS = unsquashfs.o unsquash-1.o unsquash-2.o unsquash-3.o \
57- unsquash-4.o unsquash-123.o unsquash-34.o unsquash-1234.o swap.o \
58- compressor.o unsquashfs_info.o
59+ unsquash-4.o unsquash-123.o unsquash-34.o unsquash-1234.o unsquash-12.o \
60+ swap.o compressor.o unsquashfs_info.o
61
62 CFLAGS ?= -O2
63 CFLAGS += $(EXTRA_CFLAGS) $(INCLUDEDIR) -D_FILE_OFFSET_BITS=64 \
64@@ -393,6 +393,8 @@ unsquash-34.o: unsquashfs.h unsquash-34.c unsquashfs_error.h
65
66 unsquash-1234.o: unsquash-1234.c unsquashfs_error.h
67
68+unsquash-1234.o: unsquash-12.c
69+
70 unsquashfs_xattr.o: unsquashfs_xattr.c unsquashfs.h squashfs_fs.h xattr.h unsquashfs_error.h
71
72 unsquashfs_info.o: unsquashfs.h squashfs_fs.h unsquashfs_error.h
73diff --git a/squashfs-tools/unsquash-1.c b/squashfs-tools/unsquash-1.c
74index b604434..88866fc 100644
75--- a/squashfs-tools/unsquash-1.c
76+++ b/squashfs-tools/unsquash-1.c
77@@ -370,6 +370,12 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
78 }
79 }
80
81+ /* check directory for duplicate names. Need to sort directory first */
82+ sort_directory(dir);
83+ if(check_directory(dir) == FALSE) {
84+ ERROR("File system corrupted: directory has duplicate names\n");
85+ goto corrupted;
86+ }
87 return dir;
88
89 corrupted:
90diff --git a/squashfs-tools/unsquash-12.c b/squashfs-tools/unsquash-12.c
91new file mode 100644
92index 0000000..61bf128
93--- /dev/null
94+++ b/squashfs-tools/unsquash-12.c
95@@ -0,0 +1,110 @@
96+/*
97+ * Unsquash a squashfs filesystem. This is a highly compressed read only
98+ * filesystem.
99+ *
100+ * Copyright (c) 2021
101+ * Phillip Lougher <phillip@squashfs.org.uk>
102+ *
103+ * This program is free software; you can redistribute it and/or
104+ * modify it under the terms of the GNU General Public License
105+ * as published by the Free Software Foundation; either version 2,
106+ * or (at your option) any later version.
107+ *
108+ * This program is distributed in the hope that it will be useful,
109+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
110+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
111+ * GNU General Public License for more details.
112+ *
113+ * You should have received a copy of the GNU General Public License
114+ * along with this program; if not, write to the Free Software
115+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
116+ *
117+ * unsquash-12.c
118+ *
119+ * Helper functions used by unsquash-1 and unsquash-2.
120+ */
121+
122+#include "unsquashfs.h"
123+
124+/*
125+ * Bottom up linked list merge sort.
126+ *
127+ */
128+void sort_directory(struct dir *dir)
129+{
130+ struct dir_ent *cur, *l1, *l2, *next;
131+ int len1, len2, stride = 1;
132+
133+ if(dir->dir_count < 2)
134+ return;
135+
136+ /*
137+ * We can consider our linked-list to be made up of stride length
138+ * sublists. Eacn iteration around this loop merges adjacent
139+ * stride length sublists into larger 2*stride sublists. We stop
140+ * when stride becomes equal to the entire list.
141+ *
142+ * Initially stride = 1 (by definition a sublist of 1 is sorted), and
143+ * these 1 element sublists are merged into 2 element sublists, which
144+ * are then merged into 4 element sublists and so on.
145+ */
146+ do {
147+ l2 = dir->dirs; /* head of current linked list */
148+ cur = NULL; /* empty output list */
149+
150+ /*
151+ * Iterate through the linked list, merging adjacent sublists.
152+ * On each interation l2 points to the next sublist pair to be
153+ * merged (if there's only one sublist left this is simply added
154+ * to the output list)
155+ */
156+ while(l2) {
157+ l1 = l2;
158+ for(len1 = 0; l2 && len1 < stride; len1 ++, l2 = l2->next);
159+ len2 = stride;
160+
161+ /*
162+ * l1 points to first sublist.
163+ * l2 points to second sublist.
164+ * Merge them onto the output list
165+ */
166+ while(len1 && l2 && len2) {
167+ if(strcmp(l1->name, l2->name) <= 0) {
168+ next = l1;
169+ l1 = l1->next;
170+ len1 --;
171+ } else {
172+ next = l2;
173+ l2 = l2->next;
174+ len2 --;
175+ }
176+
177+ if(cur) {
178+ cur->next = next;
179+ cur = next;
180+ } else
181+ dir->dirs = cur = next;
182+ }
183+ /*
184+ * One sublist is now empty, copy the other one onto the
185+ * output list
186+ */
187+ for(; len1; len1 --, l1 = l1->next) {
188+ if(cur) {
189+ cur->next = l1;
190+ cur = l1;
191+ } else
192+ dir->dirs = cur = l1;
193+ }
194+ for(; l2 && len2; len2 --, l2 = l2->next) {
195+ if(cur) {
196+ cur->next = l2;
197+ cur = l2;
198+ } else
199+ dir->dirs = cur = l2;
200+ }
201+ }
202+ cur->next = NULL;
203+ stride = stride << 1;
204+ } while(stride < dir->dir_count);
205+}
206diff --git a/squashfs-tools/unsquash-1234.c b/squashfs-tools/unsquash-1234.c
207index e389f8d..98a81ed 100644
208--- a/squashfs-tools/unsquash-1234.c
209+++ b/squashfs-tools/unsquash-1234.c
210@@ -72,3 +72,24 @@ void squashfs_closedir(struct dir *dir)
211
212 free(dir);
213 }
214+
215+
216+/*
217+ * Check directory for duplicate names. As the directory should be sorted,
218+ * duplicates will be consecutive. Obviously we also need to check if the
219+ * directory has been deliberately unsorted, to evade this check.
220+ */
221+int check_directory(struct dir *dir)
222+{
223+ int i;
224+ struct dir_ent *ent;
225+
226+ if(dir->dir_count < 2)
227+ return TRUE;
228+
229+ for(ent = dir->dirs, i = 0; i < dir->dir_count - 1; ent = ent->next, i++)
230+ if(strcmp(ent->name, ent->next->name) >= 0)
231+ return FALSE;
232+
233+ return TRUE;
234+}
235diff --git a/squashfs-tools/unsquash-2.c b/squashfs-tools/unsquash-2.c
236index 956f96f..0e36f7d 100644
237--- a/squashfs-tools/unsquash-2.c
238+++ b/squashfs-tools/unsquash-2.c
239@@ -29,6 +29,7 @@
240 static squashfs_fragment_entry_2 *fragment_table;
241 static unsigned int *uid_table, *guid_table;
242 static squashfs_operations ops;
243+static int needs_sorting = FALSE;
244
245
246 static void read_block_list(unsigned int *block_list, long long start,
247@@ -463,6 +464,17 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
248 }
249 }
250
251+ if(needs_sorting)
252+ sort_directory(dir);
253+
254+ /* check directory for duplicate names and sorting */
255+ if(check_directory(dir) == FALSE) {
256+ if(needs_sorting)
257+ ERROR("File system corrupted: directory has duplicate names\n");
258+ else
259+ ERROR("File system corrupted: directory has duplicate names or is unsorted\n");
260+ goto corrupted;
261+ }
262 return dir;
263
264 corrupted:
265@@ -596,6 +608,10 @@ int read_super_2(squashfs_operations **s_ops, void *s)
266 * 2.x filesystems use gzip compression.
267 */
268 comp = lookup_compressor("gzip");
269+
270+ if(sBlk_3->s_minor == 0)
271+ needs_sorting = TRUE;
272+
273 return TRUE;
274 }
275
276diff --git a/squashfs-tools/unsquash-3.c b/squashfs-tools/unsquash-3.c
277index 835a574..0123562 100644
278--- a/squashfs-tools/unsquash-3.c
279+++ b/squashfs-tools/unsquash-3.c
280@@ -497,6 +497,12 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
281 }
282 }
283
284+ /* check directory for duplicate names and sorting */
285+ if(check_directory(dir) == FALSE) {
286+ ERROR("File system corrupted: directory has duplicate names or is unsorted\n");
287+ goto corrupted;
288+ }
289+
290 return dir;
291
292 corrupted:
293diff --git a/squashfs-tools/unsquash-4.c b/squashfs-tools/unsquash-4.c
294index 694783d..c615bb8 100644
295--- a/squashfs-tools/unsquash-4.c
296+++ b/squashfs-tools/unsquash-4.c
297@@ -434,6 +434,12 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
298 }
299 }
300
301+ /* check directory for duplicate names and sorting */
302+ if(check_directory(dir) == FALSE) {
303+ ERROR("File system corrupted: directory has duplicate names or is unsorted\n");
304+ goto corrupted;
305+ }
306+
307 return dir;
308
309 corrupted:
310diff --git a/squashfs-tools/unsquashfs.h b/squashfs-tools/unsquashfs.h
311index f8cf78c..bf2a80d 100644
312--- a/squashfs-tools/unsquashfs.h
313+++ b/squashfs-tools/unsquashfs.h
314@@ -293,4 +293,8 @@ extern long long *alloc_index_table(int);
315 /* unsquash-1234.c */
316 extern int check_name(char *, int);
317 extern void squashfs_closedir(struct dir *);
318+extern int check_directory(struct dir *);
319+
320+/* unsquash-12.c */
321+extern void sort_directory(struct dir *);
322 #endif
323--
3242.17.1
325
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2026-04-22 20:57:38 +0000