[PATCH] 2.6.22.6 fix kernel panic on corrupted reiserfs directory

[PATCH] 2.6.22.6 fix kernel panic on corrupted reiserfs directory

[lepton]

Hi,
  When reading corrupted reiserfs directory data, d_reclen
  could be a negative number or a big positive number, this
  can lead to kernel panic or oop.
  The following patch adds a sanity check. (against 2.6.20.4)

Signed-off-by: Lepton Wu <ytht.net@gmail.com>

diff -X linux-2.6.22.6-lepton/Documentation/dontdiff -pru linux-2.6.22.6/fs/reiserfs/dir.c linux-2.6.22.6-lepton/fs/reiserfs/dir.c
--- linux-2.6.22.6/fs/reiserfs/dir.c	2007-09-14 17:41:15.000000000 +0800
+++ linux-2.6.22.6-lepton/fs/reiserfs/dir.c	2007-09-14 18:02:10.000000000 +0800
@@ -121,6 +121,16 @@ static int reiserfs_readdir(struct file 
 					continue;
 				d_reclen = entry_length(bh, ih, entry_num);
 				d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
+
+				if (d_reclen <= 0 ||
+				    d_name + d_reclen > bh->b_data + bh->b_size) {
+					/* There is corrupted data in entry,
+					 * We'd better stop here */
+					pathrelse(&path_to_entry);
+					ret = -EIO;
+					goto out;
+				}
+		
 				if (!d_name[d_reclen - 1])
 					d_reclen = strlen(d_name);
 

Re: [stable] [PATCH] 2.6.22.6 fix kernel panic on corrupted reiserfs directory

[Oliver Pinter]

[snap]

Hi,
  When reading corrupted reiserfs directory data, d_reclen
  could be a negative number or a big positive number, this
  can lead to kernel panic or oop.
  The following patch adds a sanity check. (against 2.6.20.4)

Signed-off-by: Lepton Wu <ytht.net@gmail.com>

diff -X linux-2.6.22.6-lepton/Documentation/dontdiff -pru
linux-2.6.22.6/fs/reiserfs/dir.c
linux-2.6.22.6-lepton/fs/reiserfs/dir.c
--- linux-2.6.22.6/fs/reiserfs/dir.c    2007-09-14 17:41:15.000000000 +0800
+++ linux-2.6.22.6-lepton/fs/reiserfs/dir.c     2007-09-14
18:02:10.000000000 +0800
@@ -121,6 +121,16 @@ static int reiserfs_readdir(struct file
                                        continue;
                                d_reclen = entry_length(bh, ih, entry_num);
                                d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
+
+                               if (d_reclen <= 0 ||
+                                   d_name + d_reclen > bh->b_data +
bh->b_size) {
+                                       /* There is corrupted data in entry,
+                                        * We'd better stop here */
+                                       pathrelse(&path_to_entry);
+                                       ret = -EIO;
+                                       goto out;
+                               }
+
                                if (!d_name[d_reclen - 1])
                                        d_reclen = strlen(d_name);

[/snap]

it is Lepton's patch.
Namesys boys, this patch is OK?
Greg, I neither do find this patch in Linus's tree.

-- 
Thanks,
Oliver

Re: [stable] [PATCH] 2.6.22.6 fix kernel panic on corrupted reiserfs directory

[Chris Wright]

* Oliver Pinter (oliver.pntr@gmail.com) wrote:
> it is Lepton's patch.
> Namesys boys, this patch is OK?
> Greg, I neither do find this patch in Linus's tree.

The point is, if it's not important enough to go into Linus' tree, than
it isn't important enough to be in the -stable tree.  So please get this
patch upstream to Linus, then we will take it for -stable.

thanks,
-chris

P.S.  When forwarding someone else's patch, always include the proper
authorship (such as "From: Lepton Wu <ytht.net@gmail.com>" in the first
line of the email body) so that information is not lost.