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NFS: Fix nfs4_verifier memory alignment
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Clean up due to code review.

The nfs4_verifier's data field is not guaranteed to be u32-aligned.
Casting an array of chars to a u32 * is considered generally
hazardous.

Fix this by using a __be32 array to generate a verifier's contents,
and then byte-copy the contents into the verifier field.  The contents
of a verifier, for all intents and purposes, are opaque bytes.  Only
local code that generates a verifier need know the actual content and
format.  Everyone else compares the full byte array for exact
equality.

Also, sizeof(nfs4_verifer) is the size of the in-core verifier data
structure, but NFS4_VERIFIER_SIZE is the number of octets in an XDR'd
verifier.  The two are not interchangeable, even if they happen to
have the same value.

Signed-off-by: Chuck Lever <[email protected]>
Signed-off-by: Trond Myklebust <[email protected]>
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@chucklever
chucklever authored and Trond Myklebust committed Mar 6, 2012
1 parent ab19b48 commit cd93710
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Showing 2 changed files with 39 additions and 33 deletions.
32 changes: 19 additions & 13 deletions fs/nfs/nfs4proc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -836,13 +836,15 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
p->o_arg.dir_bitmask = server->cache_consistency_bitmask;
p->o_arg.claim = NFS4_OPEN_CLAIM_NULL;
if (attrs != NULL && attrs->ia_valid != 0) {
u32 *s;
__be32 verf[2];

p->o_arg.u.attrs = &p->attrs;
memcpy(&p->attrs, attrs, sizeof(p->attrs));
s = (u32 *) p->o_arg.u.verifier.data;
s[0] = jiffies;
s[1] = current->pid;

verf[0] = jiffies;
verf[1] = current->pid;
memcpy(p->o_arg.u.verifier.data, verf,
sizeof(p->o_arg.u.verifier.data));
}
p->c_arg.fh = &p->o_res.fh;
p->c_arg.stateid = &p->o_res.stateid;
Expand Down Expand Up @@ -3819,6 +3821,16 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server,
return -EAGAIN;
}

static void nfs4_construct_boot_verifier(struct nfs_client *clp,
nfs4_verifier *bootverf)
{
__be32 verf[2];

verf[0] = htonl((u32)clp->cl_boot_time.tv_sec);
verf[1] = htonl((u32)clp->cl_boot_time.tv_nsec);
memcpy(bootverf->data, verf, sizeof(bootverf->data));
}

int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
unsigned short port, struct rpc_cred *cred,
struct nfs4_setclientid_res *res)
Expand All @@ -3835,13 +3847,10 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
.rpc_resp = res,
.rpc_cred = cred,
};
__be32 *p;
int loop = 0;
int status;

p = (__be32*)sc_verifier.data;
*p++ = htonl((u32)clp->cl_boot_time.tv_sec);
*p = htonl((u32)clp->cl_boot_time.tv_nsec);
nfs4_construct_boot_verifier(clp, &sc_verifier);

for(;;) {
rcu_read_lock();
Expand Down Expand Up @@ -4933,6 +4942,7 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
{
nfs4_verifier verifier;
struct nfs41_exchange_id_args args = {
.verifier = &verifier,
.client = clp,
.flags = EXCHGID4_FLAG_SUPP_MOVED_REFER,
};
Expand All @@ -4946,15 +4956,11 @@ int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
.rpc_resp = &res,
.rpc_cred = cred,
};
__be32 *p;

dprintk("--> %s\n", __func__);
BUG_ON(clp == NULL);

p = (u32 *)verifier.data;
*p++ = htonl((u32)clp->cl_boot_time.tv_sec);
*p = htonl((u32)clp->cl_boot_time.tv_nsec);
args.verifier = &verifier;
nfs4_construct_boot_verifier(clp, &verifier);

args.id_len = scnprintf(args.id, sizeof(args.id),
"%s/%s.%s/%u",
Expand Down
40 changes: 20 additions & 20 deletions fs/nfs/nfs4xdr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1538,7 +1538,7 @@ static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
FATTR4_WORD1_MOUNTED_ON_FILEID,
};
uint32_t dircount = readdir->count >> 1;
__be32 *p;
__be32 *p, verf[2];

if (readdir->plus) {
attrs[0] |= FATTR4_WORD0_TYPE|FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE|
Expand All @@ -1553,10 +1553,11 @@ static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
if (!(readdir->bitmask[1] & FATTR4_WORD1_MOUNTED_ON_FILEID))
attrs[0] |= FATTR4_WORD0_FILEID;

p = reserve_space(xdr, 12+NFS4_VERIFIER_SIZE+20);
p = reserve_space(xdr, 12);
*p++ = cpu_to_be32(OP_READDIR);
p = xdr_encode_hyper(p, readdir->cookie);
p = xdr_encode_opaque_fixed(p, readdir->verifier.data, NFS4_VERIFIER_SIZE);
encode_nfs4_verifier(xdr, &readdir->verifier);
p = reserve_space(xdr, 20);
*p++ = cpu_to_be32(dircount);
*p++ = cpu_to_be32(readdir->count);
*p++ = cpu_to_be32(2);
Expand All @@ -1565,11 +1566,11 @@ static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
*p = cpu_to_be32(attrs[1] & readdir->bitmask[1]);
hdr->nops++;
hdr->replen += decode_readdir_maxsz;
memcpy(verf, readdir->verifier.data, sizeof(verf));
dprintk("%s: cookie = %Lu, verifier = %08x:%08x, bitmap = %08x:%08x\n",
__func__,
(unsigned long long)readdir->cookie,
((u32 *)readdir->verifier.data)[0],
((u32 *)readdir->verifier.data)[1],
verf[0], verf[1],
attrs[0] & readdir->bitmask[0],
attrs[1] & readdir->bitmask[1]);
}
Expand Down Expand Up @@ -1643,9 +1644,9 @@ static void encode_setclientid(struct xdr_stream *xdr, const struct nfs4_setclie
{
__be32 *p;

p = reserve_space(xdr, 4 + NFS4_VERIFIER_SIZE);
*p++ = cpu_to_be32(OP_SETCLIENTID);
xdr_encode_opaque_fixed(p, setclientid->sc_verifier->data, NFS4_VERIFIER_SIZE);
p = reserve_space(xdr, 4);
*p = cpu_to_be32(OP_SETCLIENTID);
encode_nfs4_verifier(xdr, setclientid->sc_verifier);

encode_string(xdr, setclientid->sc_name_len, setclientid->sc_name);
p = reserve_space(xdr, 4);
Expand All @@ -1662,10 +1663,10 @@ static void encode_setclientid_confirm(struct xdr_stream *xdr, const struct nfs4
{
__be32 *p;

p = reserve_space(xdr, 12 + NFS4_VERIFIER_SIZE);
p = reserve_space(xdr, 12);
*p++ = cpu_to_be32(OP_SETCLIENTID_CONFIRM);
p = xdr_encode_hyper(p, arg->clientid);
xdr_encode_opaque_fixed(p, arg->confirm.data, NFS4_VERIFIER_SIZE);
encode_nfs4_verifier(xdr, &arg->confirm);
hdr->nops++;
hdr->replen += decode_setclientid_confirm_maxsz;
}
Expand Down Expand Up @@ -1708,9 +1709,9 @@ static void encode_exchange_id(struct xdr_stream *xdr,
char impl_name[NFS4_OPAQUE_LIMIT];
int len = 0;

p = reserve_space(xdr, 4 + sizeof(args->verifier->data));
*p++ = cpu_to_be32(OP_EXCHANGE_ID);
xdr_encode_opaque_fixed(p, args->verifier->data, sizeof(args->verifier->data));
p = reserve_space(xdr, 4);
*p = cpu_to_be32(OP_EXCHANGE_ID);
encode_nfs4_verifier(xdr, args->verifier);

encode_string(xdr, args->id_len, args->id);

Expand Down Expand Up @@ -4162,7 +4163,7 @@ static int decode_close(struct xdr_stream *xdr, struct nfs_closeres *res)

static int decode_verifier(struct xdr_stream *xdr, void *verifier)
{
return decode_opaque_fixed(xdr, verifier, 8);
return decode_opaque_fixed(xdr, verifier, NFS4_VERIFIER_SIZE);
}

static int decode_commit(struct xdr_stream *xdr, struct nfs_writeres *res)
Expand Down Expand Up @@ -4854,17 +4855,16 @@ static int decode_readdir(struct xdr_stream *xdr, struct rpc_rqst *req, struct n
size_t hdrlen;
u32 recvd, pglen = rcvbuf->page_len;
int status;
__be32 verf[2];

status = decode_op_hdr(xdr, OP_READDIR);
if (!status)
status = decode_verifier(xdr, readdir->verifier.data);
if (unlikely(status))
return status;
memcpy(verf, readdir->verifier.data, sizeof(verf));
dprintk("%s: verifier = %08x:%08x\n",
__func__,
((u32 *)readdir->verifier.data)[0],
((u32 *)readdir->verifier.data)[1]);

__func__, verf[0], verf[1]);

hdrlen = (char *) xdr->p - (char *) iov->iov_base;
recvd = rcvbuf->len - hdrlen;
Expand Down Expand Up @@ -5111,7 +5111,7 @@ static int decode_write(struct xdr_stream *xdr, struct nfs_writeres *res)
goto out_overflow;
res->count = be32_to_cpup(p++);
res->verf->committed = be32_to_cpup(p++);
memcpy(res->verf->verifier, p, 8);
memcpy(res->verf->verifier, p, NFS4_VERIFIER_SIZE);
return 0;
out_overflow:
print_overflow_msg(__func__, xdr);
Expand Down Expand Up @@ -5455,7 +5455,7 @@ static int decode_getdevicelist(struct xdr_stream *xdr,
p += 2;

/* Read verifier */
p = xdr_decode_opaque_fixed(p, verftemp.verifier, 8);
p = xdr_decode_opaque_fixed(p, verftemp.verifier, NFS4_VERIFIER_SIZE);

res->num_devs = be32_to_cpup(p);

Expand Down

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