Safer ABI for O_TMPFILE

[suggested by Rasmus Villemoes] make O_DIRECTORY | O_RDWR part of O_TMPFILE;
that will fail on old kernels in a lot more cases than what I came up with.
And make sure O_CREAT doesn't get there...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/arch/alpha/include/uapi/asm/fcntl.h b/arch/alpha/include/uapi/asm/fcntl.h
index dfdadb0b4befa6619568d8179dd68f1850ef6151..09f49a6b87d18a85451e2d457df84bb9c6f2e2ed 100644 (file)
--- a/arch/alpha/include/uapi/asm/fcntl.h
+++ b/arch/alpha/include/uapi/asm/fcntl.h
@@ -32,7 +32,7 @@
 #define O_SYNC         (__O_SYNC|O_DSYNC)
 
 #define O_PATH         040000000
-#define O_TMPFILE      0100000000
+#define __O_TMPFILE    0100000000
 
 #define F_GETLK                7
 #define F_SETLK                8

diff --git a/arch/parisc/include/uapi/asm/fcntl.h b/arch/parisc/include/uapi/asm/fcntl.h
index cc61c475f2779198e45e72dc16dcc4f51e691dec..34a46cbc76ed5d1f6f0f47bda6f0873d2448d8e2 100644 (file)
--- a/arch/parisc/include/uapi/asm/fcntl.h
+++ b/arch/parisc/include/uapi/asm/fcntl.h
@@ -20,7 +20,7 @@
 #define O_INVISIBLE    004000000 /* invisible I/O, for DMAPI/XDSM */
 
 #define O_PATH         020000000
-#define O_TMPFILE      040000000
+#define __O_TMPFILE    040000000
 
 #define F_GETLK64      8
 #define F_SETLK64      9

diff --git a/arch/sparc/include/uapi/asm/fcntl.h b/arch/sparc/include/uapi/asm/fcntl.h
index d73e5e008b0de953d5e7eaf958d5c7bfed0c45c8..7e8ace5bf760a6d2639928ce5199ec41f938b717 100644 (file)
--- a/arch/sparc/include/uapi/asm/fcntl.h
+++ b/arch/sparc/include/uapi/asm/fcntl.h
@@ -35,7 +35,7 @@
 #define O_SYNC         (__O_SYNC|O_DSYNC)
 
 #define O_PATH         0x1000000
-#define O_TMPFILE      0x2000000
+#define __O_TMPFILE    0x2000000
 
 #define F_GETOWN       5       /*  for sockets. */
 #define F_SETOWN       6       /*  for sockets. */

diff --git a/fs/namei.c b/fs/namei.c
index b2beee7a733fe3f862945f39042e04937f821741..8b61d103a8a7a15b0c5e8eab070e92f940a64b88 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2977,7 +2977,7 @@ static struct file *path_openat(int dfd, struct filename *pathname,
 
        file->f_flags = op->open_flag;
 
-       if (unlikely(file->f_flags & O_TMPFILE)) {
+       if (unlikely(file->f_flags & __O_TMPFILE)) {
                error = do_tmpfile(dfd, pathname, nd, flags, op, file, &opened);
                goto out;
        }

diff --git a/fs/open.c b/fs/open.c
index fca72c4d3f17ac13758ac5315e413d749bf7667b..9156cb050d0873b65e8083671ef0ffdbe1ff1a47 100644 (file)
--- a/fs/open.c
+++ b/fs/open.c
@@ -840,8 +840,8 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
        if (flags & __O_SYNC)
                flags |= O_DSYNC;
 
-       if (flags & O_TMPFILE) {
-               if (!(flags & O_CREAT))
+       if (flags & __O_TMPFILE) {
+               if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
                        return -EINVAL;
                acc_mode = MAY_OPEN | ACC_MODE(flags);
        } else if (flags & O_PATH) {

diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h
index 06632beaa6d515d80fc2a62c5ddca455c964e0a3..05ac354e124de3e4577667ebf292002f40f45579 100644 (file)
--- a/include/uapi/asm-generic/fcntl.h
+++ b/include/uapi/asm-generic/fcntl.h
@@ -84,10 +84,14 @@
 #define O_PATH         010000000
 #endif
 
-#ifndef O_TMPFILE
-#define O_TMPFILE      020000000
+#ifndef __O_TMPFILE
+#define __O_TMPFILE    020000000
 #endif
 
+/* a horrid kludge trying to make sure that this will fail on old kernels */
+#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY | O_RDWR)
+#define O_TMPFILE_MASK (__O_TMPFILE | O_DIRECTORY | O_CREAT | O_ACCMODE)      
+
 #ifndef O_NDELAY
 #define O_NDELAY       O_NONBLOCK
 #endif