Messages in this thread | | | Date | Sun, 24 Aug 2008 18:14:47 +0300 | From | "Pekka Enberg" <> | Subject | Re: [Patch] Fix Buffer overflow in hfsplus with a corrupted image |
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Hi Eric,
On Sun, Aug 24, 2008 at 4:07 PM, Eric Sesterhenn <snakebyte@gmx.de> wrote: > when an hfsplus image gets corrupted it might happen that the catalog > namelength field gets b0rked. If we mount such an image > the memcpy() in hfsplus_cat_build_key_uni() writes more than the 255 > that fit in the name field. Depending on the size of the overwritten > data, we either only get memory corruption or also trigger an oops like > this: > > --- linux/fs/hfsplus/catalog.c.orig 2008-08-24 14:52:03.000000000 +0200 > +++ linux/fs/hfsplus/catalog.c 2008-08-24 14:54:15.000000000 +0200 > @@ -168,6 +168,11 @@ int hfsplus_find_cat(struct super_block > return -EIO; > } > > + if (be16_to_cpu(tmp.thread.nodeName.length) >= 127) { > + printk(KERN_ERR "hfs: catalog name length corrupted\n"); > + return -EIO; > + }
So, where does this 127 come from? I can only find reference to a maximum length of 255 unicode characters (16 bits per character) in the following technical note for HFS+ (see sections "HFS Plus Names" and "Catalog Thread Records"):
http://developer.apple.com/technotes/tn/tn1150.html
Hmm?
Pekka
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