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-rw-r--r--include/linux/sunrpc/xdr.h1
-rw-r--r--net/sunrpc/auth_gss/gss_krb5_wrap.c7
-rw-r--r--net/sunrpc/auth_gss/svcauth_gss.c2
-rw-r--r--net/sunrpc/xdr.c41
4 files changed, 46 insertions, 5 deletions
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 01bb41908c93..22c207b2425f 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -184,6 +184,7 @@ 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 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 4905652e7567..cf0fd170ac18 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -580,15 +580,14 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len,
*/
movelen = min_t(unsigned int, buf->head[0].iov_len, len);
movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
- if (offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
- buf->head[0].iov_len)
- return GSS_S_FAILURE;
+ BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
+ buf->head[0].iov_len);
memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
buf->len = len - GSS_KRB5_TOK_HDR_LEN + headskip;
/* Trim off the trailing "extra count" and checksum blob */
- buf->len -= ec + GSS_KRB5_TOK_HDR_LEN + tailskip;
+ xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
*align = XDR_QUADLEN(GSS_KRB5_TOK_HDR_LEN + headskip);
*slack = *align + XDR_QUADLEN(ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index d0a2f084e5a4..50d93c49ef1a 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -906,7 +906,7 @@ 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 */
- buf->len -= 4 + round_up_to_quad(mic.len);
+ xdr_buf_trim(buf, round_up_to_quad(mic.len) + 4);
stat = 0;
out:
kfree(mic.data);
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 15b58c5144f9..6f7d82fb1eb0 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1150,6 +1150,47 @@ 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;