Messages in this thread | | | Date | Thu, 23 Aug 2012 08:12:30 -0400 | From | "J. Bruce Fields" <> | Subject | Re: [patch 4/9] fs, exportfs: Fix nil dereference if no s_export_op present |
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On Thu, Aug 23, 2012 at 02:43:27PM +0400, Cyrill Gorcunov wrote: > If there is no s_export_op present in a target superblock > we might have nil dereference.
Is that NULL dereference possible with current code, or is it a check you're adding to account for a new caller that you're about to add?
I believe it's the latter, but this would be a good thing to make clear in the changelog.
--b.
> Fix it with eplicit test > if s_export_op is provided. > > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> > CC: Pavel Emelyanov <xemul@parallels.com> > CC: Al Viro <viro@ZenIV.linux.org.uk> > CC: Alexey Dobriyan <adobriyan@gmail.com> > CC: Andrew Morton <akpm@linux-foundation.org> > CC: James Bottomley <jbottomley@parallels.com> > CC: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > CC: Alexey Dobriyan <adobriyan@gmail.com> > CC: Matthew Helsley <matt.helsley@gmail.com> > CC: "J. Bruce Fields" <bfields@fieldses.org> > CC: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > --- > fs/exportfs/expfs.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6.git/fs/exportfs/expfs.c > =================================================================== > --- linux-2.6.git.orig/fs/exportfs/expfs.c > +++ linux-2.6.git/fs/exportfs/expfs.c > @@ -357,7 +357,7 @@ int exportfs_encode_fh(struct dentry *de > */ > parent = p->d_inode; > } > - if (nop->encode_fh) > + if (nop && nop->encode_fh) > error = nop->encode_fh(inode, fid->raw, max_len, parent); > else > error = export_encode_fh(inode, fid, max_len, parent); >
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