Messages in this thread | | | Subject | Re: [PATCH] nfs client, kernel 2.4.31: readlink result overflow | From | Assar <> | Date | 12 Sep 2005 15:37:46 -0400 |
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Valdis.Kletnieks@vt.edu writes: > Odd, as it has similar code - 2.6.13-mm1 nfs2xdr.c has: > /* Convert length of symlink */ > len = ntohl(*p++); > if (len >= rcvbuf->page_len || len <= 0) {
To my reading, the 2.6.13 code does not copy the 4 bytes of length to rcvbuf.
> Is there some *other* code in 2.6 that prevents this from being a problem, > if it's a problem on 2.4? > > > diff -u linux-2.4.31.orig/fs/nfs/nfs2xdr.c linux-2.4.31/fs/nfs/nfs2xdr.c > > --- linux-2.4.31.orig/fs/nfs/nfs2xdr.c 2002-11-28 18:53:15.000000000 -0500 > > +++ linux-2.4.31/fs/nfs/nfs2xdr.c 2005-09-07 17:36:04.000000000 -0400 > > @@ -571,8 +571,8 @@ > > strlen = (u32*)kmap(rcvbuf->pages[0]); > > /* Convert length of symlink */ > > len = ntohl(*strlen); > > - if (len > rcvbuf->page_len) > > - len = rcvbuf->page_len; > > + if (len > rcvbuf->page_len - 1 - 4) > > + len = rcvbuf->page_len - 1 - 4; > > Am I the only one who finds an uncommented "-1 -4" construct scary beyond belief?
Probably not. What do you think looks better? sizeof(u32) ? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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