On Mon, Oct 19, 2020 at 01:42:27PM +0200, Martijn de Gouw wrote:
> When the passed token is longer than 4032 bytes, the remaining part
> of the token must be copied from the rqstp->rq_arg.pages. But the
> copy must make sure it happens in a consecutive way.
Thanks. Apologies, but I don't immediately see where the copy is
non-consecutive. What exactly is the bug in the existing code?
--b.
>
> Signed-off-by: Martijn de Gouw <martijn.de.g...@prodrive-technologies.com>
> ---
> net/sunrpc/auth_gss/svcauth_gss.c | 27 +++++++++++++++++----------
> 1 file changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/net/sunrpc/auth_gss/svcauth_gss.c
> b/net/sunrpc/auth_gss/svcauth_gss.c
> index 258b04372f85..bd4678db9d76 100644
> --- a/net/sunrpc/auth_gss/svcauth_gss.c
> +++ b/net/sunrpc/auth_gss/svcauth_gss.c
> @@ -1147,9 +1147,9 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp,
> struct gssp_in_token *in_token)
> {
> struct kvec *argv = &rqstp->rq_arg.head[0];
> - unsigned int page_base, length;
> - int pages, i, res;
> - size_t inlen;
> + unsigned int length, pgto_offs, pgfrom_offs;
> + int pages, i, res, pgto, pgfrom;
> + size_t inlen, to_offs, from_offs;
>
> res = gss_read_common_verf(gc, argv, authp, in_handle);
> if (res)
> @@ -1177,17 +1177,24 @@ static int gss_read_proxy_verf(struct svc_rqst *rqstp,
> memcpy(page_address(in_token->pages[0]), argv->iov_base, length);
> inlen -= length;
>
> - i = 1;
> - page_base = rqstp->rq_arg.page_base;
> + to_offs = length;
> + from_offs = rqstp->rq_arg.page_base;
> while (inlen) {
> - length = min_t(unsigned int, inlen, PAGE_SIZE);
> - memcpy(page_address(in_token->pages[i]),
> - page_address(rqstp->rq_arg.pages[i]) + page_base,
> + pgto = to_offs >> PAGE_SHIFT;
> + pgfrom = from_offs >> PAGE_SHIFT;
> + pgto_offs = to_offs & ~PAGE_MASK;
> + pgfrom_offs = from_offs & ~PAGE_MASK;
> +
> + length = min_t(unsigned int, inlen,
> + min_t(unsigned int, PAGE_SIZE - pgto_offs,
> + PAGE_SIZE - pgfrom_offs));
> + memcpy(page_address(in_token->pages[pgto]) + pgto_offs,
> + page_address(rqstp->rq_arg.pages[pgfrom]) + pgfrom_offs,
> length);
>
> + to_offs += length;
> + from_offs += length;
> inlen -= length;
> - page_base = 0;
> - i++;
> }
> return 0;
> }
> --
> 2.20.1
