[PATCH 5.6 013/194] SUNRPC: Add "@len" parameter to gss_unwrap()

From: Greg Kroah-Hartman
Date: Mon May 18 2020 - 14:15:03 EST

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From: Chuck Lever <chuck.lever@xxxxxxxxxx>

[ Upstream commit 31c9590ae468478fe47dc0f5f0d3562b2f69450e ]

Refactor: This is a pre-requisite to fixing the client-side ralign
computation in gss_unwrap_resp_priv().

The length value is passed in explicitly rather that as the value
of buf->len. This will subsequently allow gss_unwrap_kerberos_v1()
to compute a slack and align value, instead of computing it in
gss_unwrap_resp_priv().

Fixes: 35e77d21baa0 ("SUNRPC: Add rpc_auth::au_ralign field")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/linux/sunrpc/gss_api.h | 2 ++
include/linux/sunrpc/gss_krb5.h | 6 +++---
net/sunrpc/auth_gss/auth_gss.c | 4 ++--
net/sunrpc/auth_gss/gss_krb5_crypto.c | 8 ++++----
net/sunrpc/auth_gss/gss_krb5_wrap.c | 26 +++++++++++++++-----------
net/sunrpc/auth_gss/gss_mech_switch.c | 3 ++-
net/sunrpc/auth_gss/svcauth_gss.c | 8 ++------
7 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/include/linux/sunrpc/gss_api.h b/include/linux/sunrpc/gss_api.h
index 48c1b1674cbf0..e9a79518d6527 100644
--- a/include/linux/sunrpc/gss_api.h
+++ b/include/linux/sunrpc/gss_api.h
@@ -66,6 +66,7 @@ u32 gss_wrap(
u32 gss_unwrap(
struct gss_ctx *ctx_id,
int offset,
+ int len,
struct xdr_buf *inbuf);
u32 gss_delete_sec_context(
struct gss_ctx **ctx_id);
@@ -126,6 +127,7 @@ struct gss_api_ops {
u32 (*gss_unwrap)(
struct gss_ctx *ctx_id,
int offset,
+ int len,
struct xdr_buf *buf);
void (*gss_delete_sec_context)(
void *internal_ctx_id);
diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
index c1d77dd8ed416..e8f8ffe7448b2 100644
--- a/include/linux/sunrpc/gss_krb5.h
+++ b/include/linux/sunrpc/gss_krb5.h
@@ -83,7 +83,7 @@ struct gss_krb5_enctype {
u32 (*encrypt_v2) (struct krb5_ctx *kctx, u32 offset,
struct xdr_buf *buf,
struct page **pages); /* v2 encryption function */
- u32 (*decrypt_v2) (struct krb5_ctx *kctx, u32 offset,
+ u32 (*decrypt_v2) (struct krb5_ctx *kctx, u32 offset, u32 len,
struct xdr_buf *buf, u32 *headskip,
u32 *tailskip); /* v2 decryption function */
};
@@ -255,7 +255,7 @@ gss_wrap_kerberos(struct gss_ctx *ctx_id, int offset,
struct xdr_buf *outbuf, struct page **pages);

u32
-gss_unwrap_kerberos(struct gss_ctx *ctx_id, int offset,
+gss_unwrap_kerberos(struct gss_ctx *ctx_id, int offset, int len,
struct xdr_buf *buf);

@@ -312,7 +312,7 @@ gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
struct page **pages);

u32
-gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset,
+gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
struct xdr_buf *buf, u32 *plainoffset,
u32 *plainlen);

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 2dc740acb3bf3..a08a733f2d7c2 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -2041,9 +2041,9 @@ gss_unwrap_resp_priv(struct rpc_task *task, struct rpc_cred *cred,
offset = (u8 *)(p) - (u8 *)head->iov_base;
if (offset + opaque_len > rcv_buf->len)
goto unwrap_failed;
- rcv_buf->len = offset + opaque_len;

- maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset, rcv_buf);
+ maj_stat = gss_unwrap(ctx->gc_gss_ctx, offset,
+ offset + opaque_len, rcv_buf);
if (maj_stat == GSS_S_CONTEXT_EXPIRED)
clear_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags);
if (maj_stat != GSS_S_COMPLETE)
diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index 6f2d30d7b766d..e7180da1fc6a1 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -851,8 +851,8 @@ gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
}

u32
-gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
- u32 *headskip, u32 *tailskip)
+gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, u32 len,
+ struct xdr_buf *buf, u32 *headskip, u32 *tailskip)
{
struct xdr_buf subbuf;
u32 ret = 0;
@@ -881,7 +881,7 @@ gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,

/* create a segment skipping the header and leaving out the checksum */
xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
- (buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
+ (len - offset - GSS_KRB5_TOK_HDR_LEN -
kctx->gk5e->cksumlength));

nblocks = (subbuf.len + blocksize - 1) / blocksize;
@@ -926,7 +926,7 @@ gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
goto out_err;

/* Get the packet's hmac value */
- ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
+ ret = read_bytes_from_xdr_buf(buf, len - kctx->gk5e->cksumlength,
pkt_hmac, kctx->gk5e->cksumlength);
if (ret)
goto out_err;
diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c
index 6c1920eed7717..c7589e35d5d92 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -261,7 +261,8 @@ gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
}

static u32
-gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
+gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len,
+ struct xdr_buf *buf)
{
int signalg;
int sealalg;
@@ -284,7 +285,7 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)

ptr = (u8 *)buf->head[0].iov_base + offset;
if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
- buf->len - offset))
+ len - offset))
return GSS_S_DEFECTIVE_TOKEN;

if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
@@ -324,6 +325,7 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
(!kctx->initiate && direction != 0))
return GSS_S_BAD_SIG;

+ buf->len = len;
if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
struct crypto_sync_skcipher *cipher;
int err;
@@ -376,7 +378,7 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
memmove(orig_start, data_start, data_len);
buf->head[0].iov_len -= (data_start - orig_start);
- buf->len -= (data_start - orig_start);
+ buf->len = len - (data_start - orig_start);

if (gss_krb5_remove_padding(buf, blocksize))
return GSS_S_DEFECTIVE_TOKEN;
@@ -486,7 +488,8 @@ gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
}

static u32
-gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
+gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len,
+ struct xdr_buf *buf)
{
time64_t now;
u8 *ptr;
@@ -532,7 +535,7 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
if (rrc != 0)
rotate_left(offset + 16, buf, rrc);

- err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf,
+ err = (*kctx->gk5e->decrypt_v2)(kctx, offset, len, buf,
&headskip, &tailskip);
if (err)
return GSS_S_FAILURE;
@@ -542,7 +545,7 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
* it against the original
*/
err = read_bytes_from_xdr_buf(buf,
- buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip,
+ len - GSS_KRB5_TOK_HDR_LEN - tailskip,
decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
if (err) {
dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
@@ -568,14 +571,14 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
* Note that buf->head[0].iov_len may indicate the available
* head buffer space rather than that actually occupied.
*/
- movelen = min_t(unsigned int, buf->head[0].iov_len, buf->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;
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;
+ 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;
@@ -603,7 +606,8 @@ gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
}

u32
-gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
+gss_unwrap_kerberos(struct gss_ctx *gctx, int offset,
+ int len, struct xdr_buf *buf)
{
struct krb5_ctx *kctx = gctx->internal_ctx_id;

@@ -613,9 +617,9 @@ gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
case ENCTYPE_DES_CBC_RAW:
case ENCTYPE_DES3_CBC_RAW:
case ENCTYPE_ARCFOUR_HMAC:
- return gss_unwrap_kerberos_v1(kctx, offset, buf);
+ return gss_unwrap_kerberos_v1(kctx, offset, len, buf);
case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
- return gss_unwrap_kerberos_v2(kctx, offset, buf);
+ return gss_unwrap_kerberos_v2(kctx, offset, len, buf);
}
}
diff --git a/net/sunrpc/auth_gss/gss_mech_switch.c b/net/sunrpc/auth_gss/gss_mech_switch.c
index db550bfc2642e..69316ab1b9fac 100644
--- a/net/sunrpc/auth_gss/gss_mech_switch.c
+++ b/net/sunrpc/auth_gss/gss_mech_switch.c
@@ -411,10 +411,11 @@ gss_wrap(struct gss_ctx *ctx_id,
u32
gss_unwrap(struct gss_ctx *ctx_id,
int offset,
+ int len,
struct xdr_buf *buf)
{
return ctx_id->mech_type->gm_ops
- ->gss_unwrap(ctx_id, offset, buf);
+ ->gss_unwrap(ctx_id, offset, len, buf);
}

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 65b67b2573021..559053646e12c 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -928,7 +928,7 @@ static int
unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gss_ctx *ctx)
{
u32 priv_len, maj_stat;
- int pad, saved_len, remaining_len, offset;
+ int pad, remaining_len, offset;

clear_bit(RQ_SPLICE_OK, &rqstp->rq_flags);

@@ -948,12 +948,8 @@ unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gs
buf->len -= pad;
fix_priv_head(buf, pad);

- /* Maybe it would be better to give gss_unwrap a length parameter: */
- saved_len = buf->len;
- buf->len = priv_len;
- maj_stat = gss_unwrap(ctx, 0, buf);
+ maj_stat = gss_unwrap(ctx, 0, priv_len, buf);
pad = priv_len - buf->len;
- buf->len = saved_len;
buf->len -= pad;
/* The upper layers assume the buffer is aligned on 4-byte boundaries.
* In the krb5p case, at least, the data ends up offset, so we need to
--
2.20.1

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