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[68.61.232.219]) by smtp.gmail.com with ESMTPSA id 70sm5372156ity.9.2019.02.11.08.25.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 11 Feb 2019 08:25:10 -0800 (PST) Received: from manet.1015granger.net (manet.1015granger.net [192.168.1.51]) by gateway.1015granger.net (8.14.7/8.14.7) with ESMTP id x1BGP9qw030003; Mon, 11 Feb 2019 16:25:09 GMT Subject: [PATCH v1 17/23] SUNRPC: Remove xdr_buf_trim() From: Chuck Lever To: anna.schumaker@netapp.com Cc: linux-rdma@vger.kernel.org, linux-nfs@vger.kernel.org Date: Mon, 11 Feb 2019 11:25:09 -0500 Message-ID: <20190211162509.2817.29966.stgit@manet.1015granger.net> In-Reply-To: <20190211161920.2817.20881.stgit@manet.1015granger.net> References: <20190211161920.2817.20881.stgit@manet.1015granger.net> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org The key action of xdr_buf_trim() is that it shortens buf->len, the length of the xdr_buf's content. The other actions -- shortening the head, pages, and tail components -- are actually not necessary. In particular, changing the size of those components can corrupt the RPC message contained in the buffer. This is an accident waiting to happen rather than a current bug, as far as we know. Signed-off-by: Chuck Lever Acked-by: Bruce Fields --- include/linux/sunrpc/xdr.h | 1 - net/sunrpc/auth_gss/gss_krb5_wrap.c | 8 ++++--- net/sunrpc/auth_gss/svcauth_gss.c | 2 +- net/sunrpc/xdr.c | 41 ----------------------------------- 4 files changed, 6 insertions(+), 46 deletions(-) diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index 65af6a2..9ee3970 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -179,7 +179,6 @@ static inline __be32 *xdr_encode_array(__be32 *p, const void *s, unsigned int le extern void xdr_shift_buf(struct xdr_buf *, size_t); extern void xdr_buf_from_iov(struct kvec *, struct xdr_buf *); extern int xdr_buf_subsegment(struct xdr_buf *, struct xdr_buf *, unsigned int, unsigned int); -extern void xdr_buf_trim(struct xdr_buf *, unsigned int); extern int xdr_buf_read_netobj(struct xdr_buf *, struct xdr_netobj *, unsigned int); extern int read_bytes_from_xdr_buf(struct xdr_buf *, unsigned int, void *, unsigned int); extern int write_bytes_to_xdr_buf(struct xdr_buf *, unsigned int, void *, unsigned int); diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c index 5cdde6c..14a0aff 100644 --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c @@ -570,14 +570,16 @@ static void rotate_left(u32 base, struct xdr_buf *buf, unsigned int shift) */ movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len); movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip; - BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen > - buf->head[0].iov_len); + if (offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen > + buf->head[0].iov_len) + return GSS_S_FAILURE; memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen); buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip; buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip; /* Trim off the trailing "extra count" and checksum blob */ - xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip); + buf->len -= ec + GSS_KRB5_TOK_HDR_LEN + tailskip; + return GSS_S_COMPLETE; } diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 152790e..f1aabab 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -896,7 +896,7 @@ u32 svcauth_gss_flavor(struct auth_domain *dom) if (svc_getnl(&buf->head[0]) != seq) goto out; /* trim off the mic and padding at the end before returning */ - xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4); + buf->len -= 4 + round_up_to_quad(mic.len); stat = 0; out: kfree(mic.data); diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 5f0aa53..4bce619 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -1139,47 +1139,6 @@ void xdr_enter_page(struct xdr_stream *xdr, unsigned int len) } EXPORT_SYMBOL_GPL(xdr_buf_subsegment); -/** - * xdr_buf_trim - lop at most "len" bytes off the end of "buf" - * @buf: buf to be trimmed - * @len: number of bytes to reduce "buf" by - * - * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note - * that it's possible that we'll trim less than that amount if the xdr_buf is - * too small, or if (for instance) it's all in the head and the parser has - * already read too far into it. - */ -void xdr_buf_trim(struct xdr_buf *buf, unsigned int len) -{ - size_t cur; - unsigned int trim = len; - - if (buf->tail[0].iov_len) { - cur = min_t(size_t, buf->tail[0].iov_len, trim); - buf->tail[0].iov_len -= cur; - trim -= cur; - if (!trim) - goto fix_len; - } - - if (buf->page_len) { - cur = min_t(unsigned int, buf->page_len, trim); - buf->page_len -= cur; - trim -= cur; - if (!trim) - goto fix_len; - } - - if (buf->head[0].iov_len) { - cur = min_t(size_t, buf->head[0].iov_len, trim); - buf->head[0].iov_len -= cur; - trim -= cur; - } -fix_len: - buf->len -= (len - trim); -} -EXPORT_SYMBOL_GPL(xdr_buf_trim); - static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len) { unsigned int this_len;