[3.13.y.z extended stable] Patch "isofs: Fix unbounded recursion when processing relocated directories" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Tue Sep 30 21:29:28 UTC 2014
This is a note to let you know that I have just added a patch titled
isofs: Fix unbounded recursion when processing relocated directories
to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree
which can be found at:
http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue
This patch is scheduled to be released in version 3.13.11.8.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From 22eb630e0e81e7e10cd495e3b3b453fa02098b6a Mon Sep 17 00:00:00 2001
From: Jan Kara <jack at suse.cz>
Date: Sun, 17 Aug 2014 11:49:57 +0200
Subject: isofs: Fix unbounded recursion when processing relocated directories
commit 410dd3cf4c9b36f27ed4542ee18b1af5e68645a4 upstream.
We did not check relocated directory in any way when processing Rock
Ridge 'CL' tag. Thus a corrupted isofs image can possibly have a CL
entry pointing to another CL entry leading to possibly unbounded
recursion in kernel code and thus stack overflow or deadlocks (if there
is a loop created from CL entries).
Fix the problem by not allowing CL entry to point to a directory entry
with CL entry (such use makes no good sense anyway) and by checking
whether CL entry doesn't point to itself.
Reported-by: Chris Evans <cevans at google.com>
Signed-off-by: Jan Kara <jack at suse.cz>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
fs/isofs/inode.c | 15 ++++++++-------
fs/isofs/isofs.h | 23 +++++++++++++++++++----
fs/isofs/rock.c | 39 ++++++++++++++++++++++++++++-----------
3 files changed, 55 insertions(+), 22 deletions(-)
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 4a9e10e..a9daccb 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -61,7 +61,7 @@ static void isofs_put_super(struct super_block *sb)
return;
}
-static int isofs_read_inode(struct inode *);
+static int isofs_read_inode(struct inode *, int relocated);
static int isofs_statfs (struct dentry *, struct kstatfs *);
static struct kmem_cache *isofs_inode_cachep;
@@ -1258,7 +1258,7 @@ out_toomany:
goto out;
}
-static int isofs_read_inode(struct inode *inode)
+static int isofs_read_inode(struct inode *inode, int relocated)
{
struct super_block *sb = inode->i_sb;
struct isofs_sb_info *sbi = ISOFS_SB(sb);
@@ -1403,7 +1403,7 @@ static int isofs_read_inode(struct inode *inode)
*/
if (!high_sierra) {
- parse_rock_ridge_inode(de, inode);
+ parse_rock_ridge_inode(de, inode, relocated);
/* if we want uid/gid set, override the rock ridge setting */
if (sbi->s_uid_set)
inode->i_uid = sbi->s_uid;
@@ -1482,9 +1482,10 @@ static int isofs_iget5_set(struct inode *ino, void *data)
* offset that point to the underlying meta-data for the inode. The
* code below is otherwise similar to the iget() code in
* include/linux/fs.h */
-struct inode *isofs_iget(struct super_block *sb,
- unsigned long block,
- unsigned long offset)
+struct inode *__isofs_iget(struct super_block *sb,
+ unsigned long block,
+ unsigned long offset,
+ int relocated)
{
unsigned long hashval;
struct inode *inode;
@@ -1506,7 +1507,7 @@ struct inode *isofs_iget(struct super_block *sb,
return ERR_PTR(-ENOMEM);
if (inode->i_state & I_NEW) {
- ret = isofs_read_inode(inode);
+ ret = isofs_read_inode(inode, relocated);
if (ret < 0) {
iget_failed(inode);
inode = ERR_PTR(ret);
diff --git a/fs/isofs/isofs.h b/fs/isofs/isofs.h
index 9916723..0ac4c1f 100644
--- a/fs/isofs/isofs.h
+++ b/fs/isofs/isofs.h
@@ -107,7 +107,7 @@ extern int iso_date(char *, int);
struct inode; /* To make gcc happy */
-extern int parse_rock_ridge_inode(struct iso_directory_record *, struct inode *);
+extern int parse_rock_ridge_inode(struct iso_directory_record *, struct inode *, int relocated);
extern int get_rock_ridge_filename(struct iso_directory_record *, char *, struct inode *);
extern int isofs_name_translate(struct iso_directory_record *, char *, struct inode *);
@@ -118,9 +118,24 @@ extern struct dentry *isofs_lookup(struct inode *, struct dentry *, unsigned int
extern struct buffer_head *isofs_bread(struct inode *, sector_t);
extern int isofs_get_blocks(struct inode *, sector_t, struct buffer_head **, unsigned long);
-extern struct inode *isofs_iget(struct super_block *sb,
- unsigned long block,
- unsigned long offset);
+struct inode *__isofs_iget(struct super_block *sb,
+ unsigned long block,
+ unsigned long offset,
+ int relocated);
+
+static inline struct inode *isofs_iget(struct super_block *sb,
+ unsigned long block,
+ unsigned long offset)
+{
+ return __isofs_iget(sb, block, offset, 0);
+}
+
+static inline struct inode *isofs_iget_reloc(struct super_block *sb,
+ unsigned long block,
+ unsigned long offset)
+{
+ return __isofs_iget(sb, block, offset, 1);
+}
/* Because the inode number is no longer relevant to finding the
* underlying meta-data for an inode, we are free to choose a more
diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index c0bf424..f488bba 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -288,12 +288,16 @@ eio:
goto out;
}
+#define RR_REGARD_XA 1
+#define RR_RELOC_DE 2
+
static int
parse_rock_ridge_inode_internal(struct iso_directory_record *de,
- struct inode *inode, int regard_xa)
+ struct inode *inode, int flags)
{
int symlink_len = 0;
int cnt, sig;
+ unsigned int reloc_block;
struct inode *reloc;
struct rock_ridge *rr;
int rootflag;
@@ -305,7 +309,7 @@ parse_rock_ridge_inode_internal(struct iso_directory_record *de,
init_rock_state(&rs, inode);
setup_rock_ridge(de, inode, &rs);
- if (regard_xa) {
+ if (flags & RR_REGARD_XA) {
rs.chr += 14;
rs.len -= 14;
if (rs.len < 0)
@@ -485,12 +489,22 @@ repeat:
"relocated directory\n");
goto out;
case SIG('C', 'L'):
- ISOFS_I(inode)->i_first_extent =
- isonum_733(rr->u.CL.location);
- reloc =
- isofs_iget(inode->i_sb,
- ISOFS_I(inode)->i_first_extent,
- 0);
+ if (flags & RR_RELOC_DE) {
+ printk(KERN_ERR
+ "ISOFS: Recursive directory relocation "
+ "is not supported\n");
+ goto eio;
+ }
+ reloc_block = isonum_733(rr->u.CL.location);
+ if (reloc_block == ISOFS_I(inode)->i_iget5_block &&
+ ISOFS_I(inode)->i_iget5_offset == 0) {
+ printk(KERN_ERR
+ "ISOFS: Directory relocation points to "
+ "itself\n");
+ goto eio;
+ }
+ ISOFS_I(inode)->i_first_extent = reloc_block;
+ reloc = isofs_iget_reloc(inode->i_sb, reloc_block, 0);
if (IS_ERR(reloc)) {
ret = PTR_ERR(reloc);
goto out;
@@ -637,9 +651,11 @@ static char *get_symlink_chunk(char *rpnt, struct rock_ridge *rr, char *plimit)
return rpnt;
}
-int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
+int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode,
+ int relocated)
{
- int result = parse_rock_ridge_inode_internal(de, inode, 0);
+ int flags = relocated ? RR_RELOC_DE : 0;
+ int result = parse_rock_ridge_inode_internal(de, inode, flags);
/*
* if rockridge flag was reset and we didn't look for attributes
@@ -647,7 +663,8 @@ int parse_rock_ridge_inode(struct iso_directory_record *de, struct inode *inode)
*/
if ((ISOFS_SB(inode->i_sb)->s_rock_offset == -1)
&& (ISOFS_SB(inode->i_sb)->s_rock == 2)) {
- result = parse_rock_ridge_inode_internal(de, inode, 14);
+ result = parse_rock_ridge_inode_internal(de, inode,
+ flags | RR_REGARD_XA);
}
return result;
}
--
1.9.1
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