On Tue, Oct 25, 2016 at 09:47:16PM +0000, Trond Myklebust wrote:
>
> > On Oct 25, 2016, at 15:59, Fields Bruce James <bfields@xxxxxxxxxxxx> wrote:
> >
> > On Tue, Oct 25, 2016 at 07:34:43PM +0000, Trond Myklebust wrote:
> >> NACK… I agree that there may already be borkage in RPCSEC_GSS-land, but that’s not a reason to be adding to the pile of things that need to be fixed… The allocations that lie in the RPC client’s encode/decode path do need to be GFP_NOFS….
> >
> > OK. Any disadvantage to keeping this patch with just GFP_NOFS
> > allocations everywhere that might be in the write path?
>
> It’s what we have to do everywhere else in the RPC client, so I can’t see why it should be a problem.
OK, the below is what I intend to merge if nobody spots another problem.
--b.
commit 2876a34466ce
Author: J. Bruce Fields <bfields@xxxxxxxxxx>
Date: Tue Oct 18 16:30:09 2016 -0400
sunrpc: don't pass on-stack memory to sg_set_buf
As of ac4e97abce9b "scatterlist: sg_set_buf() argument must be in linear
mapping", sg_set_buf hits a BUG when make_checksum_v2->xdr_process_buf,
among other callers, passes it memory on the stack.
We only need a scatterlist to pass this to the crypto code, and it seems
like overkill to require kmalloc'd memory just to encrypt a few bytes,
but for now this seems the best fix.
Many of these callers are in the NFS write paths, so we allocate with
GFP_NOFS. It might be possible to do without allocations here entirely,
but that would probably be a bigger project.
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index d8bd97a5a7c9..3dfd769dc5b5 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -1616,7 +1616,7 @@ gss_validate(struct rpc_task *task, __be32 *p)
{
struct rpc_cred *cred = task->tk_rqstp->rq_cred;
struct gss_cl_ctx *ctx = gss_cred_get_ctx(cred);
- __be32 seq;
+ __be32 *seq = NULL;
struct kvec iov;
struct xdr_buf verf_buf;
struct xdr_netobj mic;
@@ -1631,9 +1631,12 @@ gss_validate(struct rpc_task *task, __be32 *p)
goto out_bad;
if (flav != RPC_AUTH_GSS)
goto out_bad;
- seq = htonl(task->tk_rqstp->rq_seqno);
- iov.iov_base = &seq;
- iov.iov_len = sizeof(seq);
+ seq = kmalloc(4, GFP_NOFS);
+ if (!seq)
+ goto out_bad;
+ *seq = htonl(task->tk_rqstp->rq_seqno);
+ iov.iov_base = seq;
+ iov.iov_len = 4;
xdr_buf_from_iov(&iov, &verf_buf);
mic.data = (u8 *)p;
mic.len = len;
@@ -1653,11 +1656,13 @@ gss_validate(struct rpc_task *task, __be32 *p)
gss_put_ctx(ctx);
dprintk("RPC: %5u %s: gss_verify_mic succeeded.\n",
task->tk_pid, __func__);
+ kfree(seq);
return p + XDR_QUADLEN(len);
out_bad:
gss_put_ctx(ctx);
dprintk("RPC: %5u %s failed ret %ld.\n", task->tk_pid, __func__,
PTR_ERR(ret));
+ kfree(seq);
return ret;
}
diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index 244245bcbbd2..90115ceefd49 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -166,8 +166,8 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
unsigned int usage, struct xdr_netobj *cksumout)
{
struct scatterlist sg[1];
- int err;
- u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
+ int err = -1;
+ u8 *checksumdata;
u8 rc4salt[4];
struct crypto_ahash *md5;
struct crypto_ahash *hmac_md5;
@@ -187,23 +187,22 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
return GSS_S_FAILURE;
}
+ checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
+ if (!checksumdata)
+ return GSS_S_FAILURE;
+
md5 = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(md5))
- return GSS_S_FAILURE;
+ goto out_free_cksum;
hmac_md5 = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0,
CRYPTO_ALG_ASYNC);
- if (IS_ERR(hmac_md5)) {
- crypto_free_ahash(md5);
- return GSS_S_FAILURE;
- }
+ if (IS_ERR(hmac_md5))
+ goto out_free_md5;
req = ahash_request_alloc(md5, GFP_KERNEL);
- if (!req) {
- crypto_free_ahash(hmac_md5);
- crypto_free_ahash(md5);
- return GSS_S_FAILURE;
- }
+ if (!req)
+ goto out_free_hmac_md5;
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
@@ -232,11 +231,8 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
ahash_request_free(req);
req = ahash_request_alloc(hmac_md5, GFP_KERNEL);
- if (!req) {
- crypto_free_ahash(hmac_md5);
- crypto_free_ahash(md5);
- return GSS_S_FAILURE;
- }
+ if (!req)
+ goto out_free_hmac_md5;
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
@@ -258,8 +254,12 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
cksumout->len = kctx->gk5e->cksumlength;
out:
ahash_request_free(req);
- crypto_free_ahash(md5);
+out_free_hmac_md5:
crypto_free_ahash(hmac_md5);
+out_free_md5:
+ crypto_free_ahash(md5);
+out_free_cksum:
+ kfree(checksumdata);
return err ? GSS_S_FAILURE : 0;
}
@@ -276,8 +276,8 @@ make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
struct crypto_ahash *tfm;
struct ahash_request *req;
struct scatterlist sg[1];
- int err;
- u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
+ int err = -1;
+ u8 *checksumdata;
unsigned int checksumlen;
if (kctx->gk5e->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR)
@@ -291,15 +291,17 @@ make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
return GSS_S_FAILURE;
}
+ checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
+ if (checksumdata == NULL)
+ return GSS_S_FAILURE;
+
tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm))
- return GSS_S_FAILURE;
+ goto out_free_cksum;
req = ahash_request_alloc(tfm, GFP_KERNEL);
- if (!req) {
- crypto_free_ahash(tfm);
- return GSS_S_FAILURE;
- }
+ if (!req)
+ goto out_free_ahash;
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
@@ -349,7 +351,10 @@ make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
cksumout->len = kctx->gk5e->cksumlength;
out:
ahash_request_free(req);
+out_free_ahash:
crypto_free_ahash(tfm);
+out_free_cksum:
+ kfree(checksumdata);
return err ? GSS_S_FAILURE : 0;
}
@@ -368,8 +373,8 @@ make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
struct crypto_ahash *tfm;
struct ahash_request *req;
struct scatterlist sg[1];
- int err;
- u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
+ int err = -1;
+ u8 *checksumdata;
unsigned int checksumlen;
if (kctx->gk5e->keyed_cksum == 0) {
@@ -383,16 +388,18 @@ make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
return GSS_S_FAILURE;
}
+ checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
+ if (!checksumdata)
+ return GSS_S_FAILURE;
+
tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(tfm))
- return GSS_S_FAILURE;
+ goto out_free_cksum;
checksumlen = crypto_ahash_digestsize(tfm);
req = ahash_request_alloc(tfm, GFP_KERNEL);
- if (!req) {
- crypto_free_ahash(tfm);
- return GSS_S_FAILURE;
- }
+ if (!req)
+ goto out_free_ahash;
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
@@ -433,7 +440,10 @@ make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
}
out:
ahash_request_free(req);
+out_free_ahash:
crypto_free_ahash(tfm);
+out_free_cksum:
+ kfree(checksumdata);
return err ? GSS_S_FAILURE : 0;
}
@@ -666,14 +676,17 @@ gss_krb5_cts_crypt(struct crypto_skcipher *cipher, struct xdr_buf *buf,
u32 ret;
struct scatterlist sg[1];
SKCIPHER_REQUEST_ON_STACK(req, cipher);
- u8 data[GSS_KRB5_MAX_BLOCKSIZE * 2];
+ u8 *data;
struct page **save_pages;
u32 len = buf->len - offset;
- if (len > ARRAY_SIZE(data)) {
+ if (len > GSS_KRB5_MAX_BLOCKSIZE * 2) {
WARN_ON(0);
return -ENOMEM;
}
+ data = kmalloc(GSS_KRB5_MAX_BLOCKSIZE * 2, GFP_NOFS);
+ if (!data)
+ return -ENOMEM;
/*
* For encryption, we want to read from the cleartext
@@ -708,6 +721,7 @@ gss_krb5_cts_crypt(struct crypto_skcipher *cipher, struct xdr_buf *buf,
ret = write_bytes_to_xdr_buf(buf, offset, data, len);
out:
+ kfree(data);
return ret;
}
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index d67f7e1bc82d..45662d7f0943 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -718,30 +718,37 @@ gss_write_null_verf(struct svc_rqst *rqstp)
static int
gss_write_verf(struct svc_rqst *rqstp, struct gss_ctx *ctx_id, u32 seq)
{
- __be32 xdr_seq;
+ __be32 *xdr_seq;
u32 maj_stat;
struct xdr_buf verf_data;
struct xdr_netobj mic;
__be32 *p;
struct kvec iov;
+ int err = -1;
svc_putnl(rqstp->rq_res.head, RPC_AUTH_GSS);
- xdr_seq = htonl(seq);
+ xdr_seq = kmalloc(4, GFP_KERNEL);
+ if (!xdr_seq)
+ return -1;
+ *xdr_seq = htonl(seq);
- iov.iov_base = &xdr_seq;
- iov.iov_len = sizeof(xdr_seq);
+ iov.iov_base = xdr_seq;
+ iov.iov_len = 4;
xdr_buf_from_iov(&iov, &verf_data);
p = rqstp->rq_res.head->iov_base + rqstp->rq_res.head->iov_len;
mic.data = (u8 *)(p + 1);
maj_stat = gss_get_mic(ctx_id, &verf_data, &mic);
if (maj_stat != GSS_S_COMPLETE)
- return -1;
+ goto out;
*p++ = htonl(mic.len);
memset((u8 *)p + mic.len, 0, round_up_to_quad(mic.len) - mic.len);
p += XDR_QUADLEN(mic.len);
if (!xdr_ressize_check(rqstp, p))
- return -1;
- return 0;
+ goto out;
+ err = 0;
+out:
+ kfree(xdr_seq);
+ return err;
}
struct gss_domain {
--
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