From 241b1f419f0ea9966d574d7cc67377c74982a125 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 11 Feb 2019 11:25:09 -0500 Subject: SUNRPC: Remove xdr_buf_trim() 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 Signed-off-by: Anna Schumaker --- 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 65af6a204b75..9ee3970ba59c 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -179,7 +179,6 @@ xdr_adjust_iovec(struct kvec *iov, __be32 *p) 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 5cdde6cb703a..14a0aff0cd84 100644 --- a/net/sunrpc/auth_gss/gss_krb5_wrap.c +++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c @@ -570,14 +570,16 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf) */ 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 152790ed309c..f1aabab4a4c2 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -896,7 +896,7 @@ unwrap_integ_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct g 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 5f0aa53fa4ae..4bce61978062 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -1139,47 +1139,6 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf, } 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; -- cgit v1.2.3