My recent "ACCESS in OPEN" patch that fixed permissions due to OPEN operations
having no way to differentiate between READ and EXEC had several issues:
- when files are opened O_EXCL, ACCESS will always return permission denied
for all bits until close is called.
- POSIX allows processes to write to files without write permissions if
that process created the file
Don't check MAY_WRITE as a newly created file may not have write mode bits,
but POSIX allows the creating process to write regardless.
This is ok because NFSv4 OPEN ops handle write permissions correctly -
the ACCESS in the OPEN compound is to differentiate READ v EXEC permissions.
Signed-off-by: Weston Andros Adamson <[email protected]>
---
fs/nfs/nfs4proc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 1e0faf9..ccada68 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1661,10 +1661,10 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
return 0;
mask = 0;
+ /* don't check MAY_WRITE - a newly created file may not have
+ * write mode bits, but POSIX allows the creating process to write */
if (fmode & FMODE_READ)
mask |= MAY_READ;
- if (fmode & FMODE_WRITE)
- mask |= MAY_WRITE;
if (fmode & FMODE_EXEC)
mask |= MAY_EXEC;
@@ -1673,7 +1673,7 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
nfs_access_set_mask(&cache, opendata->o_res.access_result);
nfs_access_add_cache(state->inode, &cache);
- if ((mask & ~cache.mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)
+ if ((mask & ~cache.mask & (MAY_READ | MAY_EXEC)) == 0)
return 0;
/* even though OPEN succeeded, access is denied. Close the file */
--
1.7.9.6 (Apple Git-31.1)
Don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
will return permission denied for all bits until close.
Signed-off-by: Weston Andros Adamson <[email protected]>
---
fs/nfs/nfs4proc.c | 12 +++++++++---
fs/nfs/nfs4xdr.c | 12 ++++++++----
include/linux/nfs_xdr.h | 1 +
3 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ccada68..21cfac7 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -862,9 +862,15 @@ static struct nfs4_opendata *nfs4_opendata_alloc(struct dentry *dentry,
p->o_arg.fh = NFS_FH(dir);
p->o_arg.open_flags = flags;
p->o_arg.fmode = fmode & (FMODE_READ|FMODE_WRITE);
- /* ask server to check for all possible rights as results are cached */
- p->o_arg.access = NFS4_ACCESS_READ | NFS4_ACCESS_MODIFY |
- NFS4_ACCESS_EXTEND | NFS4_ACCESS_EXECUTE;
+ /* don't put an ACCESS op in OPEN compound if O_EXCL, because ACCESS
+ * will return permission denied for all bits until close */
+ if (!(flags & O_EXCL)) {
+ /* ask server to check for all possible rights as results
+ * are cached */
+ p->o_arg.access = NFS4_ACCESS_READ | NFS4_ACCESS_MODIFY |
+ NFS4_ACCESS_EXTEND | NFS4_ACCESS_EXECUTE;
+ p->o_res.access_request = p->o_arg.access;
+ }
p->o_arg.clientid = server->nfs_client->cl_clientid;
p->o_arg.id.create_time = ktime_to_ns(sp->so_seqid.create_time);
p->o_arg.id.uniquifier = sp->so_seqid.owner_id;
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 657483c..0d60305 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -2224,7 +2224,8 @@ static void nfs4_xdr_enc_open(struct rpc_rqst *req, struct xdr_stream *xdr,
encode_putfh(xdr, args->fh, &hdr);
encode_open(xdr, args, &hdr);
encode_getfh(xdr, &hdr);
- encode_access(xdr, args->access, &hdr);
+ if (args->access)
+ encode_access(xdr, args->access, &hdr);
encode_getfattr_open(xdr, args->bitmask, args->open_bitmap, &hdr);
encode_nops(&hdr);
}
@@ -2261,7 +2262,8 @@ static void nfs4_xdr_enc_open_noattr(struct rpc_rqst *req,
encode_sequence(xdr, &args->seq_args, &hdr);
encode_putfh(xdr, args->fh, &hdr);
encode_open(xdr, args, &hdr);
- encode_access(xdr, args->access, &hdr);
+ if (args->access)
+ encode_access(xdr, args->access, &hdr);
encode_getfattr(xdr, args->bitmask, &hdr);
encode_nops(&hdr);
}
@@ -6239,7 +6241,8 @@ static int nfs4_xdr_dec_open(struct rpc_rqst *rqstp, struct xdr_stream *xdr,
status = decode_getfh(xdr, &res->fh);
if (status)
goto out;
- decode_access(xdr, &res->access_supported, &res->access_result);
+ if (res->access_request)
+ decode_access(xdr, &res->access_supported, &res->access_result);
decode_getfattr(xdr, res->f_attr, res->server);
out:
return status;
@@ -6288,7 +6291,8 @@ static int nfs4_xdr_dec_open_noattr(struct rpc_rqst *rqstp,
status = decode_open(xdr, res);
if (status)
goto out;
- decode_access(xdr, &res->access_supported, &res->access_result);
+ if (res->access_request)
+ decode_access(xdr, &res->access_supported, &res->access_result);
decode_getfattr(xdr, res->f_attr, res->server);
out:
return status;
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 655490d..a73ea89 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -369,6 +369,7 @@ struct nfs_openres {
struct nfs4_string *owner;
struct nfs4_string *group_owner;
struct nfs4_sequence_res seq_res;
+ __u32 access_request;
__u32 access_supported;
__u32 access_result;
};
--
1.7.9.6 (Apple Git-31.1)