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squashfs-tools: CVE-2021-41072 additional write outside destination directory exploit fix

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This commit is contained in:
Abhi Das 2023-09-13 22:30:13 -05:00 committed by Stepan Oksanichenko
parent 098684359c
commit 63e99e62af
3 changed files with 597 additions and 1 deletions
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3
.squashfs-tools.metadata Normal file
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@ -0,0 +1,3 @@
ccdbdb36be907de767019f2f35e985c6fad1bc2c 4.4-git.1.tar.gz
35fd7f626fc3259edce72cb0e3f3656a90d1e03f mksquashfs.1
e9e8ab48d8d38eae19affcd515a94497d21199ac unsquashfs.1

587
CVE-2021-41072-c9s-combined.patch Normal file
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@ -0,0 +1,587 @@
diff -Nupr a/squashfs-tools/Makefile b/squashfs-tools/Makefile
--- a/squashfs-tools/Makefile 2023-06-26 23:18:33.104153303 -0500
+++ b/squashfs-tools/Makefile 2023-06-26 23:19:49.230107688 -0500
@@ -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.
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
diff -Nupr a/squashfs-tools/unsquash-1234.c b/squashfs-tools/unsquash-1234.c
--- a/squashfs-tools/unsquash-1234.c 2023-06-26 23:18:33.104153303 -0500
+++ b/squashfs-tools/unsquash-1234.c 2023-06-26 23:19:49.230107688 -0500
@@ -25,8 +25,8 @@
* unsquash-4.
*/
-#define TRUE 1
-#define FALSE 0
+#include "unsquashfs.h"
+
/*
* Check name for validity, name should not
* - be ".", "./", or
@@ -56,3 +56,40 @@ int check_name(char *name, int size)
return TRUE;
}
+
+
+void squashfs_closedir(struct dir *dir)
+{
+ struct dir_ent *ent = dir->dirs;
+
+ while(ent) {
+ struct dir_ent *tmp = ent;
+
+ ent = ent->next;
+ free(tmp->name);
+ free(tmp);
+ }
+
+ 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 -Nupr a/squashfs-tools/unsquash-12.c b/squashfs-tools/unsquash-12.c
--- a/squashfs-tools/unsquash-12.c 1969-12-31 18:00:00.000000000 -0600
+++ b/squashfs-tools/unsquash-12.c 2023-06-26 23:19:49.230107688 -0500
@@ -0,0 +1,103 @@
+/*
+ * 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. Each 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;
+ }
+ }
+ cur->next = NULL;
+ stride = stride << 1;
+ } while(stride < dir->dir_count);
+}
diff -Nupr a/squashfs-tools/unsquash-1.c b/squashfs-tools/unsquash-1.c
--- a/squashfs-tools/unsquash-1.c 2023-06-26 23:18:33.104153303 -0500
+++ b/squashfs-tools/unsquash-1.c 2023-06-26 23:19:49.230107688 -0500
@@ -207,7 +207,7 @@ static struct dir *squashfs_opendir(unsi
long long start;
int bytes;
int dir_count, size;
- struct dir_ent *new_dir;
+ struct dir_ent *ent, *cur_ent = NULL;
struct dir *dir;
TRACE("squashfs_opendir: inode start block %d, offset %d\n",
@@ -220,7 +220,7 @@ static struct dir *squashfs_opendir(unsi
EXIT_UNSQUASH("squashfs_opendir: malloc failed!\n");
dir->dir_count = 0;
- dir->cur_entry = 0;
+ dir->cur_entry = NULL;
dir->mode = (*i)->mode;
dir->uid = (*i)->uid;
dir->guid = (*i)->gid;
@@ -295,29 +295,36 @@ static struct dir *squashfs_opendir(unsi
TRACE("squashfs_opendir: directory entry %s, inode "
"%d:%d, type %d\n", dire->name,
dirh.start_block, dire->offset, dire->type);
- if((dir->dir_count % DIR_ENT_SIZE) == 0) {
- new_dir = realloc(dir->dirs, (dir->dir_count +
- DIR_ENT_SIZE) * sizeof(struct dir_ent));
- if(new_dir == NULL)
- EXIT_UNSQUASH("squashfs_opendir: "
- "realloc failed!\n");
- dir->dirs = new_dir;
- }
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
- dir->dirs[dir->dir_count].start_block =
- dirh.start_block;
- dir->dirs[dir->dir_count].offset = dire->offset;
- dir->dirs[dir->dir_count].type = dire->type;
+
+ ent = malloc(sizeof(struct dir_ent));
+ if(ent == NULL)
+ MEM_ERROR();
+
+ ent->name = strdup(dire->name);
+ ent->start_block = dirh.start_block;
+ ent->offset = dire->offset;
+ ent->type = dire->type;
+ ent->next = NULL;
+ if (cur_ent == NULL)
+ dir->dirs = ent;
+ else
+ cur_ent->next = ent;
+ cur_ent = ent;
dir->dir_count ++;
bytes += dire->size + 1;
}
}
+ /* 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:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff -Nupr a/squashfs-tools/unsquash-2.c b/squashfs-tools/unsquash-2.c
--- a/squashfs-tools/unsquash-2.c 2023-06-26 23:18:33.104153303 -0500
+++ b/squashfs-tools/unsquash-2.c 2023-06-26 23:19:49.230107688 -0500
@@ -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;
+int needs_sorting = FALSE;
static void read_block_list(unsigned int *block_list, char *block_ptr, int blocks)
{
@@ -308,7 +309,7 @@ static struct dir *squashfs_opendir(unsi
long long start;
int bytes;
int dir_count, size;
- struct dir_ent *new_dir;
+ struct dir_ent *ent, *cur_ent = NULL;
struct dir *dir;
TRACE("squashfs_opendir: inode start block %d, offset %d\n",
@@ -321,7 +322,7 @@ static struct dir *squashfs_opendir(unsi
EXIT_UNSQUASH("squashfs_opendir: malloc failed!\n");
dir->dir_count = 0;
- dir->cur_entry = 0;
+ dir->cur_entry = NULL;
dir->mode = (*i)->mode;
dir->uid = (*i)->uid;
dir->guid = (*i)->gid;
@@ -396,29 +397,41 @@ static struct dir *squashfs_opendir(unsi
TRACE("squashfs_opendir: directory entry %s, inode "
"%d:%d, type %d\n", dire->name,
dirh.start_block, dire->offset, dire->type);
- if((dir->dir_count % DIR_ENT_SIZE) == 0) {
- new_dir = realloc(dir->dirs, (dir->dir_count +
- DIR_ENT_SIZE) * sizeof(struct dir_ent));
- if(new_dir == NULL)
- EXIT_UNSQUASH("squashfs_opendir: "
- "realloc failed!\n");
- dir->dirs = new_dir;
- }
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
- dir->dirs[dir->dir_count].start_block =
- dirh.start_block;
- dir->dirs[dir->dir_count].offset = dire->offset;
- dir->dirs[dir->dir_count].type = dire->type;
+
+ ent = malloc(sizeof(struct dir_ent));
+ if (ent == NULL)
+ MEM_ERROR();
+
+ ent->name = strdup(dire->name);
+ ent->start_block = dirh.start_block;
+ ent->offset = dire->offset;
+ ent->type = dire->type;
+ ent->next = NULL;
+ if (cur_ent == NULL)
+ dir->dirs = ent;
+ else
+ cur_ent->next = ent;
+ cur_ent = ent;
dir->dir_count ++;
bytes += dire->size + 1;
}
}
+ 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:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff -Nupr a/squashfs-tools/unsquash-3.c b/squashfs-tools/unsquash-3.c
--- a/squashfs-tools/unsquash-3.c 2023-06-26 23:18:33.105153302 -0500
+++ b/squashfs-tools/unsquash-3.c 2023-06-26 23:19:49.230107688 -0500
@@ -334,7 +334,7 @@ static struct dir *squashfs_opendir(unsi
long long start;
int bytes;
int dir_count, size;
- struct dir_ent *new_dir;
+ struct dir_ent *ent, *cur_ent = NULL;
struct dir *dir;
TRACE("squashfs_opendir: inode start block %d, offset %d\n",
@@ -347,7 +347,7 @@ static struct dir *squashfs_opendir(unsi
EXIT_UNSQUASH("squashfs_opendir: malloc failed!\n");
dir->dir_count = 0;
- dir->cur_entry = 0;
+ dir->cur_entry = NULL;
dir->mode = (*i)->mode;
dir->uid = (*i)->uid;
dir->guid = (*i)->gid;
@@ -423,29 +423,36 @@ static struct dir *squashfs_opendir(unsi
TRACE("squashfs_opendir: directory entry %s, inode "
"%d:%d, type %d\n", dire->name,
dirh.start_block, dire->offset, dire->type);
- if((dir->dir_count % DIR_ENT_SIZE) == 0) {
- new_dir = realloc(dir->dirs, (dir->dir_count +
- DIR_ENT_SIZE) * sizeof(struct dir_ent));
- if(new_dir == NULL)
- EXIT_UNSQUASH("squashfs_opendir: "
- "realloc failed!\n");
- dir->dirs = new_dir;
- }
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
- dir->dirs[dir->dir_count].start_block =
- dirh.start_block;
- dir->dirs[dir->dir_count].offset = dire->offset;
- dir->dirs[dir->dir_count].type = dire->type;
+
+ ent = malloc(sizeof(struct dir_ent));
+ if (ent == NULL)
+ MEM_ERROR();
+
+ ent->name = strdup(dire->name);
+ ent->start_block = dirh.start_block;
+ ent->offset = dire->offset;
+ ent->type = dire->type;
+ ent->next = NULL;
+ if (cur_ent == NULL)
+ dir->dirs = ent;
+ else
+ cur_ent->next = ent;
+ cur_ent = ent;
dir->dir_count ++;
bytes += dire->size + 1;
}
}
+ /* 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:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff -Nupr a/squashfs-tools/unsquash-4.c b/squashfs-tools/unsquash-4.c
--- a/squashfs-tools/unsquash-4.c 2023-06-26 23:18:33.105153302 -0500
+++ b/squashfs-tools/unsquash-4.c 2023-06-26 23:19:49.231107688 -0500
@@ -281,7 +281,7 @@ static struct dir *squashfs_opendir(unsi
long long start;
long long bytes;
int dir_count, size;
- struct dir_ent *new_dir;
+ struct dir_ent *ent, *cur_ent = NULL;
struct dir *dir;
TRACE("squashfs_opendir: inode start block %d, offset %d\n",
@@ -294,7 +294,7 @@ static struct dir *squashfs_opendir(unsi
EXIT_UNSQUASH("squashfs_opendir: malloc failed!\n");
dir->dir_count = 0;
- dir->cur_entry = 0;
+ dir->cur_entry = NULL;
dir->mode = (*i)->mode;
dir->uid = (*i)->uid;
dir->guid = (*i)->gid;
@@ -359,29 +359,36 @@ static struct dir *squashfs_opendir(unsi
TRACE("squashfs_opendir: directory entry %s, inode "
"%d:%d, type %d\n", dire->name,
dirh.start_block, dire->offset, dire->type);
- if((dir->dir_count % DIR_ENT_SIZE) == 0) {
- new_dir = realloc(dir->dirs, (dir->dir_count +
- DIR_ENT_SIZE) * sizeof(struct dir_ent));
- if(new_dir == NULL)
- EXIT_UNSQUASH("squashfs_opendir: "
- "realloc failed!\n");
- dir->dirs = new_dir;
- }
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
- dir->dirs[dir->dir_count].start_block =
- dirh.start_block;
- dir->dirs[dir->dir_count].offset = dire->offset;
- dir->dirs[dir->dir_count].type = dire->type;
+
+ ent = malloc(sizeof(struct dir_ent));
+ if (ent == NULL)
+ MEM_ERROR();
+
+ ent->name = strdup(dire->name);
+ ent->start_block = dirh.start_block;
+ ent->offset = dire->offset;
+ ent->type = dire->type;
+ ent->next = NULL;
+ if (cur_ent == NULL)
+ dir->dirs = ent;
+ else
+ cur_ent->next = ent;
+ cur_ent = ent;
dir->dir_count ++;
bytes += dire->size + 1;
}
}
+ /* 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:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff -Nupr a/squashfs-tools/unsquashfs.c b/squashfs-tools/unsquashfs.c
--- a/squashfs-tools/unsquashfs.c 2023-06-26 23:18:33.105153302 -0500
+++ b/squashfs-tools/unsquashfs.c 2023-06-26 23:19:49.231107688 -0500
@@ -78,6 +78,7 @@ int user_xattrs = FALSE;
int ignore_errors = FALSE;
int strict_errors = FALSE;
int use_localtime = TRUE;
+extern int needs_sorting;
int lookup_type[] = {
0,
@@ -1287,26 +1288,23 @@ failed:
int squashfs_readdir(struct dir *dir, char **name, unsigned int *start_block,
unsigned int *offset, unsigned int *type)
{
- if(dir->cur_entry == dir->dir_count)
+ if(dir->cur_entry == NULL)
+ dir->cur_entry = dir->dirs;
+ else
+ dir->cur_entry = dir->cur_entry->next;
+
+ if (dir->cur_entry == NULL)
return FALSE;
- *name = dir->dirs[dir->cur_entry].name;
- *start_block = dir->dirs[dir->cur_entry].start_block;
- *offset = dir->dirs[dir->cur_entry].offset;
- *type = dir->dirs[dir->cur_entry].type;
- dir->cur_entry ++;
+ *name = dir->cur_entry->name;
+ *start_block = dir->cur_entry->start_block;
+ *offset = dir->cur_entry->offset;
+ *type = dir->cur_entry->type;
return TRUE;
}
-void squashfs_closedir(struct dir *dir)
-{
- free(dir->dirs);
- free(dir);
-}
-
-
char *get_component(char *target, char **targname)
{
char *start;
@@ -1959,6 +1957,10 @@ int read_super(char *source)
* 1.x, 2.x and 3.x filesystems use gzip compression.
*/
comp = lookup_compressor("gzip");
+
+ if (sBlk_3.s_minor == 0)
+ needs_sorting = TRUE;
+
return TRUE;
failed_mount:
diff -Nupr a/squashfs-tools/unsquashfs.h b/squashfs-tools/unsquashfs.h
--- a/squashfs-tools/unsquashfs.h 2023-06-26 23:18:33.106153301 -0500
+++ b/squashfs-tools/unsquashfs.h 2023-06-26 23:19:49.231107688 -0500
@@ -165,21 +165,22 @@ struct queue {
#define DIR_ENT_SIZE 16
struct dir_ent {
- char name[SQUASHFS_NAME_LEN + 1];
+ char *name;
unsigned int start_block;
unsigned int offset;
unsigned int type;
+ struct dir_ent *next;
};
struct dir {
int dir_count;
- int cur_entry;
unsigned int mode;
uid_t uid;
gid_t guid;
unsigned int mtime;
unsigned int xattr;
struct dir_ent *dirs;
+ struct dir_ent *cur_entry;
};
struct file_entry {
@@ -264,4 +265,9 @@ 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

8
squashfs-tools.spec
View File

@ -2,7 +2,7 @@ Summary: Utility for the creation of squashfs filesystems
%global forgeurl https://github.com/plougher/squashfs-tools
Version: 4.4
Name: squashfs-tools
Release: 9.git1%{?dist}
Release: 10.git1%{?dist}
License: GPLv2+
URL: %{forgeurl}/archive/4.4-git.1.tar.gz
Source: 4.4-git.1.tar.gz
@ -13,6 +13,7 @@ Source2: unsquashfs.1
Patch0: bz2023218.patch
Patch1: bz2000638.patch
Patch2: CVE-2021-41072-c9s-combined.patch
BuildRequires: make
BuildRequires: gcc
@ -31,6 +32,7 @@ contains the utilities for manipulating squashfs filesystems.
%setup -n %{name}-4.4-git.1
%patch0 -p1
%patch1 -p1
%patch2 -p1
%build
%set_build_flags
@ -54,6 +56,10 @@ install -m 644 %{SOURCE2} %{buildroot}%{_mandir}/man1/unsquashfs.1
%{_sbindir}/unsquashfs
%changelog
* Wed Sep 13 2023 Abhi Das <adas@redhat.com> - 4.4-10.git1
- CVE-2021-41072 squashfs-tools: additional write outside destination directory exploit fix
rhbz#2007304
* Mon May 30 2022 Abhi Das <adas@redhat.com> - 4.4-9.git1
- CVE-2021-40153 squashfs-tools: unvalidated filepaths allow writing outside of destination
rhbz#2000638