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SubjectRe: [reiserfs-list] major security bug in reiserfs (may affect SuSE Linux)


On Wednesday, January 10, 2001 02:32:09 AM +0100 Marc Lehmann <pcg@goof.com> wrote:

>>> EIP; c013f911 <filldir+20b/221> <=====
> Trace; c013f706 <filldir+0/221>
> Trace; c0136e01 <reiserfs_getblk+2a/16d>

The buffer reiserfs is sending to filldir is big enough for
the huge file name, so I think the real fix should be done in VFSland.

But, in the interest of providing a quick, obviously correct fix, this
reiserfs only patch will refuse to create file names larger
than 255 chars, and skip over any directory entries larger than
255 chars.

--- linux/include/linux/reiserfs_fs.h.1 Tue Jan 9 21:56:18 2001
+++ linux/include/linux/reiserfs_fs.h Tue Jan 9 21:56:33 2001
@@ -467,7 +467,7 @@
/* name by bh, ih and entry_num */
#define B_I_E_NAME(entry_num,bh,ih) ((char *)(bh->b_data + ih->ih_item_location + (B_I_DEH(bh,ih)+(entry_num))->deh_location))

-#define REISERFS_MAX_NAME_LEN(block_size) (block_size - BLKH_SIZE - IH_SIZE - DEH_SIZE) /* -SD_SIZE when entry will contain stat data */
+#define REISERFS_MAX_NAME_LEN(block_size) 255

/* this structure is used for operations on directory entries. It is not a disk structure. */
/* When reiserfs_find_entry or search_by_entry_key find directory entry, they return filled reiserfs_dir_entry structure */
--- linux/fs/reiserfs/dir.c.1 Tue Jan 9 22:06:06 2001
+++ linux/fs/reiserfs/dir.c Tue Jan 9 22:15:17 2001
@@ -159,6 +159,10 @@
d_name = B_I_DEH_ENTRY_FILE_NAME (bh, ih, deh);
d_off = deh->deh_offset;
d_ino = deh->deh_objectid;
+ if (d_reclen > REISERFS_MAX_NAME_LEN(inode->i_sb->s_blocksize)){
+ /* it is too big to send back to VFS */
+ continue ;
+ }
if (d_reclen <= 32) {
local_buf = small_buf ;
} else {
-
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