Messages in this thread | | | Date | Mon, 23 Nov 2009 16:16:13 +0300 | From | Anton Vorontsov <> | Subject | Re: [PATCH] jffs2: Fix memory corruption in jffs2_read_inode_range() |
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On Sun, Nov 22, 2009 at 10:20:59AM +0000, David Woodhouse wrote: > On Fri, 2009-11-20 at 12:45 -0700, Anton Vorontsov wrote: > > + if (pg->index > ((i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT)) { > > + ret = 0; > > + memset(pg_buf, 0, PAGE_CACHE_SIZE); > > + } else { > > + ret = jffs2_read_inode_range(c, f, pg_buf, > > + pg->index << PAGE_CACHE_SHIFT, PAGE_CACHE_SIZE); > > + } > > Thank you for the excellent diagnosis and the patch. > > I think I'd prefer to fix it a little differently though -- I would be > happier to make jffs2_read_inode_range() cope with out-of-file reads, > rather than adding this special case where we don't call it. > > That way we aren't at all susceptible to potential races between the > VFS-maintained i_size and our own internal fragtree handling. And > jffs2_read_inode_range() already handles the memset to zero for various > other reasons anyway. > > Does this patch look OK to you? It seems to work on the test cases I've > tried.
Yep, it looks good (and works).
Thanks David!
-- Anton Vorontsov email: cbouatmailru@gmail.com irc://irc.freenode.net/bd2
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