Messages in this thread Patch in this message | | | Subject | Re: [PATCH] nfs client, kernel 2.4.31: readlink result overflow | From | Assar <> | Date | 12 Sep 2005 16:41:19 -0400 |
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Valdis.Kletnieks@vt.edu writes: > > To my reading, the 2.6.13 code does not copy the 4 bytes of length to > > rcvbuf. > > Hmm... it still does this: > kaddr[len+rcvbuf->page_base] = '\0'; > which still has a possible off-by-one? (Was that why you have -1 -4?)
The check is different. 2.6.13 is using ">=" instead of ">", so hence I think that's fine.
> sizeof(actual_var) is even better, as that way it's clear what you're allowing > space for.
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 2005-09-12 16:12:30.000000000 -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 - sizeof(*strlen) - 1) + len = rcvbuf->page_len - sizeof(*strlen) - 1; *strlen = len; /* NULL terminate the string we got */ string = (char *)(strlen + 1); diff -u linux-2.4.31.orig/fs/nfs/nfs3xdr.c linux-2.4.31/fs/nfs/nfs3xdr.c --- linux-2.4.31.orig/fs/nfs/nfs3xdr.c 2003-11-28 13:26:21.000000000 -0500 +++ linux-2.4.31/fs/nfs/nfs3xdr.c 2005-09-12 16:12:29.000000000 -0400 @@ -759,8 +759,8 @@ 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 - sizeof(*strlen) - 1) + len = rcvbuf->page_len - sizeof(*strlen) - 1; *strlen = len; /* NULL terminate the string we got */ string = (char *)(strlen + 1); - 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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