From: Weston Andros Adamson <dros@netapp.com>
Date: Thu, 3 Jan 2013 21:42:29 +0000 (-0500)
Subject: NFS: Fix access to suid/sgid executables
X-Git-Tag: v3.7.2~74
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5865afd9e73a8981f38344ddcb42d9f2049c1469;p=karo-tx-linux.git

NFS: Fix access to suid/sgid executables

commit f8d9a897d4384b77f13781ea813156568f68b83e upstream.

nfs_open_permission_mask() should only check MAY_EXEC for files that
are opened with __FMODE_EXEC.

Also fix NFSv4 access-in-open path in a similar way -- openflags must be
used because fmode will not always have FMODE_EXEC set.

This patch fixes https://bugzilla.kernel.org/show_bug.cgi?id=49101

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a1aa28254bec..c99f07ea416a 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -2148,12 +2148,16 @@ static int nfs_open_permission_mask(int openflags)
 {
 	int mask = 0;
 
-	if ((openflags & O_ACCMODE) != O_WRONLY)
-		mask |= MAY_READ;
-	if ((openflags & O_ACCMODE) != O_RDONLY)
-		mask |= MAY_WRITE;
-	if (openflags & __FMODE_EXEC)
-		mask |= MAY_EXEC;
+	if (openflags & __FMODE_EXEC) {
+		/* ONLY check exec rights */
+		mask = MAY_EXEC;
+	} else {
+		if ((openflags & O_ACCMODE) != O_WRONLY)
+			mask |= MAY_READ;
+		if ((openflags & O_ACCMODE) != O_RDONLY)
+			mask |= MAY_WRITE;
+	}
+
 	return mask;
 }
 
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ee21395f579c..4432b2f50540 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1721,7 +1721,8 @@ static int _nfs4_recover_proc_open(struct nfs4_opendata *data)
 
 static int nfs4_opendata_access(struct rpc_cred *cred,
 				struct nfs4_opendata *opendata,
-				struct nfs4_state *state, fmode_t fmode)
+				struct nfs4_state *state, fmode_t fmode,
+				int openflags)
 {
 	struct nfs_access_entry cache;
 	u32 mask;
@@ -1733,11 +1734,14 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
 
 	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_EXEC)
-		mask |= MAY_EXEC;
+	 * write mode bits, but POSIX allows the creating process to write.
+	 * use openflags to check for exec, because fmode won't
+	 * always have FMODE_EXEC set when file open for exec. */
+	if (openflags & __FMODE_EXEC) {
+		/* ONLY check for exec rights */
+		mask = MAY_EXEC;
+	} else if (fmode & FMODE_READ)
+		mask = MAY_READ;
 
 	cache.cred = cred;
 	cache.jiffies = jiffies;
@@ -2009,7 +2013,7 @@ static int _nfs4_do_open(struct inode *dir,
 	if (server->caps & NFS_CAP_POSIX_LOCK)
 		set_bit(NFS_STATE_POSIX_LOCKS, &state->flags);
 
-	status = nfs4_opendata_access(cred, opendata, state, fmode);
+	status = nfs4_opendata_access(cred, opendata, state, fmode, flags);
 	if (status != 0)
 		goto err_opendata_put;