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squashfs-tools: fix CVE-2021-41072

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Backport patches to fix CVE-2021-41072. And update context for verison
4.4 at same time.

CVE: CVE-2021-41072

Ref:
* https://nvd.nist.gov/vuln/detail/CVE-2021-41072

(From OE-Core rev: e95ccf6f7fe5a42fffcfa5e43087ff964622e26c)

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Kai Kang
2021-11-18 09:53:36 +08:00
committed by Richard Purdie
parent 39ee281be1
commit a0745dce6b
5 changed files with 894 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

135
meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072-requisite-1.patch Normal file
View File

@@ -0,0 +1,135 @@
The commit is required by the fix for CVE-2021-41072.
Upstream-Status: Backport [https://github.com/plougher/squashfs-tools/commit/80b8441]
Signed-off-by: Kai Kang <kai.kang@windriver.com>
From 80b8441a37fcf8bf07dacf24d9d6c6459a0f6e36 Mon Sep 17 00:00:00 2001
From: Phillip Lougher <phillip@squashfs.org.uk>
Date: Sun, 12 Sep 2021 19:58:19 +0100
Subject: [PATCH] unsquashfs: use squashfs_closedir() to delete directory
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
squashfs-tools/unsquash-1.c | 3 +--
squashfs-tools/unsquash-1234.c | 11 +++++++++--
squashfs-tools/unsquash-2.c | 3 +--
squashfs-tools/unsquash-3.c | 3 +--
squashfs-tools/unsquash-4.c | 3 +--
squashfs-tools/unsquashfs.c | 7 -------
squashfs-tools/unsquashfs.h | 1 +
7 files changed, 14 insertions(+), 17 deletions(-)
diff --git a/squashfs-tools/unsquash-1.c b/squashfs-tools/unsquash-1.c
index acba821..7598499 100644
--- a/squashfs-tools/unsquash-1.c
+++ b/squashfs-tools/unsquash-1.c
@@ -373,8 +373,7 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
return dir;
corrupted:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff --git a/squashfs-tools/unsquash-1234.c b/squashfs-tools/unsquash-1234.c
index c2d4f42..0c8dfbb 100644
--- a/squashfs-tools/unsquash-1234.c
+++ b/squashfs-tools/unsquash-1234.c
@@ -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 +56,10 @@ int check_name(char *name, int size)
return TRUE;
}
+
+
+void squashfs_closedir(struct dir *dir)
+{
+ free(dir->dirs);
+ free(dir);
+}
diff --git a/squashfs-tools/unsquash-2.c b/squashfs-tools/unsquash-2.c
index 0746b3d..86f62ba 100644
--- a/squashfs-tools/unsquash-2.c
+++ b/squashfs-tools/unsquash-2.c
@@ -465,8 +465,7 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
return dir;
corrupted:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff --git a/squashfs-tools/unsquash-3.c b/squashfs-tools/unsquash-3.c
index 094caaa..c04aa9e 100644
--- a/squashfs-tools/unsquash-3.c
+++ b/squashfs-tools/unsquash-3.c
@@ -499,8 +499,7 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
return dir;
corrupted:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff --git a/squashfs-tools/unsquash-4.c b/squashfs-tools/unsquash-4.c
index 3a1b9e1..ff62dcc 100644
--- a/squashfs-tools/unsquash-4.c
+++ b/squashfs-tools/unsquash-4.c
@@ -436,8 +436,7 @@ static struct dir *squashfs_opendir(unsigned int block_start, unsigned int offse
return dir;
corrupted:
- free(dir->dirs);
- free(dir);
+ squashfs_closedir(dir);
return NULL;
}
diff --git a/squashfs-tools/unsquashfs.c b/squashfs-tools/unsquashfs.c
index 7b590bd..04be53c 100644
--- a/squashfs-tools/unsquashfs.c
+++ b/squashfs-tools/unsquashfs.c
@@ -1350,13 +1350,6 @@ unsigned int *offset, unsigned int *type)
}
-void squashfs_closedir(struct dir *dir)
-{
- free(dir->dirs);
- free(dir);
-}
-
-
char *get_component(char *target, char **targname)
{
char *start;
diff --git a/squashfs-tools/unsquashfs.h b/squashfs-tools/unsquashfs.h
index 2e9201c..5ecb2ab 100644
--- a/squashfs-tools/unsquashfs.h
+++ b/squashfs-tools/unsquashfs.h
@@ -291,4 +291,5 @@ extern long long *alloc_index_table(int);
/* unsquash-1234.c */
extern int check_name(char *, int);
+extern void squashfs_closedir(struct dir *);
#endif
--
2.17.1

109
meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072-requisite-2.patch Normal file
View File

@@ -0,0 +1,109 @@
The commit is required by the fix for CVE-2021-41072. Update context for
version 4.4.
Upstream-Status: Backport [https://github.com/plougher/squashfs-tools/commit/1993a4e]
Signed-off-by: Kai Kang <kai.kang@windriver.com>
From 1993a4e7aeda04962bf26e84c15fba8b58837e10 Mon Sep 17 00:00:00 2001
From: Phillip Lougher <phillip@squashfs.org.uk>
Date: Sun, 12 Sep 2021 20:09:13 +0100
Subject: [PATCH] unsquashfs: dynamically allocate name
Dynamically allocate name rather than store it
directly in structure.
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
squashfs-tools/unsquash-1.c | 2 +-
squashfs-tools/unsquash-1234.c | 5 +++++
squashfs-tools/unsquash-2.c | 2 +-
squashfs-tools/unsquash-3.c | 2 +-
squashfs-tools/unsquash-4.c | 2 +-
squashfs-tools/unsquashfs.h | 2 +-
6 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/squashfs-tools/unsquash-1.c b/squashfs-tools/unsquash-1.c
index 7598499..d0121c6 100644
--- a/squashfs-tools/unsquash-1.c
+++ b/squashfs-tools/unsquash-1.c
@@ -303,7 +303,7 @@ static struct dir *squashfs_opendir(unsi
"realloc failed!\n");
dir->dirs = new_dir;
}
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
+ dir->dirs[dir->dir_count].name = strdup(dire->name);
dir->dirs[dir->dir_count].start_block =
dirh.start_block;
dir->dirs[dir->dir_count].offset = dire->offset;
diff --git a/squashfs-tools/unsquash-1234.c b/squashfs-tools/unsquash-1234.c
index 0c8dfbb..ac46d9d 100644
--- a/squashfs-tools/unsquash-1234.c
+++ b/squashfs-tools/unsquash-1234.c
@@ -60,6 +60,11 @@ int check_name(char *name, int size)
void squashfs_closedir(struct dir *dir)
{
+ int i;
+
+ for(i = 0; i < dir->dir_count; i++)
+ free(dir->dirs[i].name);
+
free(dir->dirs);
free(dir);
}
diff --git a/squashfs-tools/unsquash-2.c b/squashfs-tools/unsquash-2.c
index 86f62ba..e847980 100644
--- a/squashfs-tools/unsquash-2.c
+++ b/squashfs-tools/unsquash-2.c
@@ -404,7 +404,7 @@ static struct dir *squashfs_opendir(unsi
"realloc failed!\n");
dir->dirs = new_dir;
}
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
+ dir->dirs[dir->dir_count].name = strdup(dire->name);
dir->dirs[dir->dir_count].start_block =
dirh.start_block;
dir->dirs[dir->dir_count].offset = dire->offset;
diff --git a/squashfs-tools/unsquash-3.c b/squashfs-tools/unsquash-3.c
index c04aa9e..8223f27 100644
--- a/squashfs-tools/unsquash-3.c
+++ b/squashfs-tools/unsquash-3.c
@@ -431,7 +431,7 @@ static struct dir *squashfs_opendir(unsi
"realloc failed!\n");
dir->dirs = new_dir;
}
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
+ dir->dirs[dir->dir_count].name = strdup(dire->name);
dir->dirs[dir->dir_count].start_block =
dirh.start_block;
dir->dirs[dir->dir_count].offset = dire->offset;
diff --git a/squashfs-tools/unsquash-4.c b/squashfs-tools/unsquash-4.c
index ff62dcc..1e199a7 100644
--- a/squashfs-tools/unsquash-4.c
+++ b/squashfs-tools/unsquash-4.c
@@ -367,7 +367,7 @@ static struct dir *squashfs_opendir(unsi
"realloc failed!\n");
dir->dirs = new_dir;
}
- strcpy(dir->dirs[dir->dir_count].name, dire->name);
+ dir->dirs[dir->dir_count].name = strdup(dire->name);
dir->dirs[dir->dir_count].start_block =
dirh.start_block;
dir->dirs[dir->dir_count].offset = dire->offset;
diff --git a/squashfs-tools/unsquashfs.h b/squashfs-tools/unsquashfs.h
index 5ecb2ab..583fbe4 100644
--- a/squashfs-tools/unsquashfs.h
+++ b/squashfs-tools/unsquashfs.h
@@ -165,7 +165,7 @@ 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;
--
2.17.1

330
meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072-requisite-3.patch Normal file
View File

@@ -0,0 +1,330 @@
The commit is required by the fix for CVE-2021-41072. Update context for
version 4.4.
Upstream-Status: Backport [https://github.com/plougher/squashfs-tools/commit/9938154]
Signed-off-by: Kai Kang <kai.kang@windriver.com>
From 9938154174756ee48a94ea0b076397a2944b028d Mon Sep 17 00:00:00 2001
From: Phillip Lougher <phillip@squashfs.org.uk>
Date: Sun, 12 Sep 2021 22:58:11 +0100
Subject: [PATCH] unsquashfs: use linked list to store directory names
This should bring higher performance, and it allows sorting
if necessary (1.x and 2.0 filesystems).
Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
---
squashfs-tools/unsquash-1.c | 30 +++++++++++++++---------------
squashfs-tools/unsquash-1234.c | 12 ++++++++----
squashfs-tools/unsquash-2.c | 29 +++++++++++++++--------------
squashfs-tools/unsquash-3.c | 29 +++++++++++++++--------------
squashfs-tools/unsquash-4.c | 29 +++++++++++++++--------------
squashfs-tools/unsquashfs.c | 16 ++++++++++------
squashfs-tools/unsquashfs.h | 3 ++-
7 files changed, 80 insertions(+), 68 deletions(-)
diff --git a/squashfs-tools/unsquash-1.c b/squashfs-tools/unsquash-1.c
index d0121c6..b604434 100644
--- a/squashfs-tools/unsquash-1.c
+++ b/squashfs-tools/unsquash-1.c
@@ -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;
@@ -295,19 +295,20 @@ 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;
- }
- dir->dirs[dir->dir_count].name = strdup(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;
}
diff --git a/squashfs-tools/unsquash-1234.c b/squashfs-tools/unsquash-1234.c
index ac46d9d..e389f8d 100644
--- a/squashfs-tools/unsquash-1234.c
+++ b/squashfs-tools/unsquash-1234.c
@@ -60,11 +60,15 @@ int check_name(char *name, int size)
void squashfs_closedir(struct dir *dir)
{
- int i;
+ struct dir_ent *ent = dir->dirs;
- for(i = 0; i < dir->dir_count; i++)
- free(dir->dirs[i].name);
+ while(ent) {
+ struct dir_ent *tmp = ent;
+
+ ent = ent->next;
+ free(tmp->name);
+ free(tmp);
+ }
- free(dir->dirs);
free(dir);
}
diff --git a/squashfs-tools/unsquash-2.c b/squashfs-tools/unsquash-2.c
index e847980..956f96f 100644
--- a/squashfs-tools/unsquash-2.c
+++ b/squashfs-tools/unsquash-2.c
@@ -308,7 +308,7 @@ 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 +321,7 @@ 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;
@@ -396,19 +396,20 @@ 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;
- }
- dir->dirs[dir->dir_count].name = strdup(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;
}
diff --git a/squashfs-tools/unsquash-3.c b/squashfs-tools/unsquash-3.c
index 8223f27..835a574 100644
--- a/squashfs-tools/unsquash-3.c
+++ b/squashfs-tools/unsquash-3.c
@@ -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;
@@ -423,19 +423,20 @@ 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;
- }
- dir->dirs[dir->dir_count].name = strdup(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;
}
diff --git a/squashfs-tools/unsquash-4.c b/squashfs-tools/unsquash-4.c
index 1e199a7..694783d 100644
--- a/squashfs-tools/unsquash-4.c
+++ b/squashfs-tools/unsquash-4.c
@@ -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;
@@ -359,19 +359,20 @@ 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;
- }
- dir->dirs[dir->dir_count].name = strdup(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;
}
diff --git a/squashfs-tools/unsquashfs.c b/squashfs-tools/unsquashfs.c
index 04be53c..fee28ec 100644
--- a/squashfs-tools/unsquashfs.c
+++ b/squashfs-tools/unsquashfs.c
@@ -1277,14 +1277,18 @@ 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;
}
diff --git a/squashfs-tools/unsquashfs.h b/squashfs-tools/unsquashfs.h
index 583fbe4..f8cf78c 100644
--- a/squashfs-tools/unsquashfs.h
+++ b/squashfs-tools/unsquashfs.h
@@ -169,17 +169,18 @@ struct dir_ent {
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 {
--
2.17.1

316
meta/recipes-devtools/squashfs-tools/files/CVE-2021-41072.patch Normal file
View File

@@ -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

4
meta/recipes-devtools/squashfs-tools/squashfs-tools_git.bb
View File

@@ -12,6 +12,10 @@ SRCREV = "52eb4c279cd283ed9802dd1ceb686560b22ffb67"
SRC_URI = "git://github.com/plougher/squashfs-tools.git;protocol=https;branch=master \
file://0001-squashfs-tools-fix-build-failure-against-gcc-10.patch;striplevel=2 \
file://CVE-2021-40153.patch;striplevel=2 \
file://CVE-2021-41072-requisite-1.patch;striplevel=2 \
file://CVE-2021-41072-requisite-2.patch;striplevel=2 \
file://CVE-2021-41072-requisite-3.patch;striplevel=2 \
file://CVE-2021-41072.patch;striplevel=2 \
"
S = "${WORKDIR}/git/squashfs-tools"