[PATCH 1/2] NFSv4: Handle open for execute correctly

[PATCH 1/2] NFSv4: Handle open for execute correctly

[Trond Myklebust]

When mapping the NFSv4 context to an open mode and access mode,
we need to treat the FMODE_EXEC flag differently. For the open
mode, FMODE_EXEC means we need read share access. For the access
mode checking, we need to verify that the user actually has
execute access.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/nfs4proc.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 6418cb6c079b..26626ea1f197 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1165,6 +1165,18 @@ static bool nfs4_clear_cap_atomic_open_v1(struct nfs_server *server,
 	return true;
 }
 
+static fmode_t _nfs4_ctx_to_accessmode(const struct nfs_open_context *ctx)
+{
+	 return ctx->mode & (FMODE_READ|FMODE_WRITE|FMODE_EXEC);
+}
+
+static fmode_t _nfs4_ctx_to_openmode(const struct nfs_open_context *ctx)
+{
+	fmode_t ret = ctx->mode & (FMODE_READ|FMODE_WRITE);
+
+	return (ctx->mode & FMODE_EXEC) ? FMODE_READ | ret : ret;
+}
+
 static u32
 nfs4_map_atomic_open_share(struct nfs_server *server,
 		fmode_t fmode, int openflags)
@@ -2900,14 +2912,13 @@ static unsigned nfs4_exclusive_attrset(struct nfs4_opendata *opendata,
 }
 
 static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
-		fmode_t fmode,
-		int flags,
-		struct nfs_open_context *ctx)
+		int flags, struct nfs_open_context *ctx)
 {
 	struct nfs4_state_owner *sp = opendata->owner;
 	struct nfs_server *server = sp->so_server;
 	struct dentry *dentry;
 	struct nfs4_state *state;
+	fmode_t acc_mode = _nfs4_ctx_to_accessmode(ctx);
 	unsigned int seq;
 	int ret;
 
@@ -2946,7 +2957,8 @@ static int _nfs4_open_and_get_state(struct nfs4_opendata *opendata,
 	/* Parse layoutget results before we check for access */
 	pnfs_parse_lgopen(state->inode, opendata->lgp, ctx);
 
-	ret = nfs4_opendata_access(sp->so_cred, opendata, state, fmode, flags);
+	ret = nfs4_opendata_access(sp->so_cred, opendata, state,
+			acc_mode, flags);
 	if (ret != 0)
 		goto out;
 
@@ -2978,7 +2990,7 @@ static int _nfs4_do_open(struct inode *dir,
 	struct dentry *dentry = ctx->dentry;
 	const struct cred *cred = ctx->cred;
 	struct nfs4_threshold **ctx_th = &ctx->mdsthreshold;
-	fmode_t fmode = ctx->mode & (FMODE_READ|FMODE_WRITE|FMODE_EXEC);
+	fmode_t fmode = _nfs4_ctx_to_openmode(ctx);
 	enum open_claim_type4 claim = NFS4_OPEN_CLAIM_NULL;
 	struct iattr *sattr = c->sattr;
 	struct nfs4_label *label = c->label;
@@ -3024,7 +3036,7 @@ static int _nfs4_do_open(struct inode *dir,
 	if (d_really_is_positive(dentry))
 		opendata->state = nfs4_get_open_state(d_inode(dentry), sp);
 
-	status = _nfs4_open_and_get_state(opendata, fmode, flags, ctx);
+	status = _nfs4_open_and_get_state(opendata, flags, ctx);
 	if (status != 0)
 		goto err_free_label;
 	state = ctx->state;
@@ -3594,9 +3606,9 @@ static void nfs4_close_context(struct nfs_open_context *ctx, int is_sync)
 	if (ctx->state == NULL)
 		return;
 	if (is_sync)
-		nfs4_close_sync(ctx->state, ctx->mode);
+		nfs4_close_sync(ctx->state, _nfs4_ctx_to_openmode(ctx));
 	else
-		nfs4_close_state(ctx->state, ctx->mode);
+		nfs4_close_state(ctx->state, _nfs4_ctx_to_openmode(ctx));
 }
 
 #define FATTR4_WORD1_NFS40_MASK (2*FATTR4_WORD1_MOUNTED_ON_FILEID - 1UL)
-- 
2.21.0

[PATCH 2/2] NFSv4: Handle the special Linux file open access mode

[Trond Myklebust]

According to the open() manpage, Linux reserves the access mode 3
to mean "check for read and write permission on the file and return
a file descriptor that can't be used for reading or writing."

Currently, the NFSv4 code will ask the server to open the file,
and will use an incorrect share access mode of 0. Since it has
an incorrect share access mode, the client later forgets to send
a corresponding close, meaning it can leak stateids on the server.

Fixes: ce4ef7c0a8a05 ("NFS: Split out NFS v4 file operations")
Cc: stable@vger.kernel.org # 3.6+
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/inode.c    | 1 +
 fs/nfs/nfs4file.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 0b4a1a974411..53777813ca95 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1100,6 +1100,7 @@ int nfs_open(struct inode *inode, struct file *filp)
 	nfs_fscache_open_file(inode, filp);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(nfs_open);
 
 /*
  * This function is called whenever some part of NFS notices that
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index cf42a8b939e3..3a507c42c1ca 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -49,7 +49,7 @@ nfs4_file_open(struct inode *inode, struct file *filp)
 		return err;
 
 	if ((openflags & O_ACCMODE) == 3)
-		openflags--;
+		return nfs_open(inode, filp);
 
 	/* We can't create new files here */
 	openflags &= ~(O_CREAT|O_EXCL);
-- 
2.21.0