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-rw-r--r--arch/alpha/include/uapi/asm/ioctls.h1
-rw-r--r--arch/mips/include/uapi/asm/ioctls.h1
-rw-r--r--arch/parisc/include/uapi/asm/ioctls.h1
-rw-r--r--arch/powerpc/include/uapi/asm/ioctls.h1
-rw-r--r--arch/sh/include/uapi/asm/ioctls.h1
-rw-r--r--arch/sparc/include/uapi/asm/ioctls.h3
-rw-r--r--arch/xtensa/include/uapi/asm/ioctls.h1
-rw-r--r--drivers/tty/pty.c71
-rw-r--r--include/uapi/asm-generic/ioctls.h1
9 files changed, 76 insertions, 5 deletions
diff --git a/arch/alpha/include/uapi/asm/ioctls.h b/arch/alpha/include/uapi/asm/ioctls.h
index f30c94ae1bdb..ff67b8373bf7 100644
--- a/arch/alpha/include/uapi/asm/ioctls.h
+++ b/arch/alpha/include/uapi/asm/ioctls.h
@@ -100,6 +100,7 @@
#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */
+#define TIOCGPTPEER _IOR('T', 0x41, int) /* Safely open the slave */
#define TIOCSERCONFIG 0x5453
#define TIOCSERGWILD 0x5454
diff --git a/arch/mips/include/uapi/asm/ioctls.h b/arch/mips/include/uapi/asm/ioctls.h
index 740219c2c894..68e19b689a00 100644
--- a/arch/mips/include/uapi/asm/ioctls.h
+++ b/arch/mips/include/uapi/asm/ioctls.h
@@ -91,6 +91,7 @@
#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */
+#define TIOCGPTPEER _IOR('T', 0x41, int) /* Safely open the slave */
/* I hope the range from 0x5480 on is free ... */
#define TIOCSCTTY 0x5480 /* become controlling tty */
diff --git a/arch/parisc/include/uapi/asm/ioctls.h b/arch/parisc/include/uapi/asm/ioctls.h
index b6572f051b67..674c68a5bbd0 100644
--- a/arch/parisc/include/uapi/asm/ioctls.h
+++ b/arch/parisc/include/uapi/asm/ioctls.h
@@ -60,6 +60,7 @@
#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */
+#define TIOCGPTPEER _IOR('T', 0x41, int) /* Safely open the slave */
#define FIONCLEX 0x5450 /* these numbers need to be adjusted. */
#define FIOCLEX 0x5451
diff --git a/arch/powerpc/include/uapi/asm/ioctls.h b/arch/powerpc/include/uapi/asm/ioctls.h
index 49a25796a61a..bfd609a3e928 100644
--- a/arch/powerpc/include/uapi/asm/ioctls.h
+++ b/arch/powerpc/include/uapi/asm/ioctls.h
@@ -100,6 +100,7 @@
#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */
+#define TIOCGPTPEER _IOR('T', 0x41, int) /* Safely open the slave */
#define TIOCSERCONFIG 0x5453
#define TIOCSERGWILD 0x5454
diff --git a/arch/sh/include/uapi/asm/ioctls.h b/arch/sh/include/uapi/asm/ioctls.h
index c9903e56ccf4..eec7901e9e65 100644
--- a/arch/sh/include/uapi/asm/ioctls.h
+++ b/arch/sh/include/uapi/asm/ioctls.h
@@ -93,6 +93,7 @@
#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */
+#define TIOCGPTPEER _IOR('T', 0x41, int) /* Safely open the slave */
#define TIOCSERCONFIG _IO('T', 83) /* 0x5453 */
#define TIOCSERGWILD _IOR('T', 84, int) /* 0x5454 */
diff --git a/arch/sparc/include/uapi/asm/ioctls.h b/arch/sparc/include/uapi/asm/ioctls.h
index 06b3f6c3bb9a..6d27398632ea 100644
--- a/arch/sparc/include/uapi/asm/ioctls.h
+++ b/arch/sparc/include/uapi/asm/ioctls.h
@@ -27,7 +27,7 @@
#define TIOCGRS485 _IOR('T', 0x41, struct serial_rs485)
#define TIOCSRS485 _IOWR('T', 0x42, struct serial_rs485)
-/* Note that all the ioctls that are not available in Linux have a
+/* Note that all the ioctls that are not available in Linux have a
* double underscore on the front to: a) avoid some programs to
* think we support some ioctls under Linux (autoconfiguration stuff)
*/
@@ -88,6 +88,7 @@
#define TIOCGPTN _IOR('t', 134, unsigned int) /* Get Pty Number */
#define TIOCSPTLCK _IOW('t', 135, int) /* Lock/unlock PTY */
#define TIOCSIG _IOW('t', 136, int) /* Generate signal on Pty slave */
+#define TIOCGPTPEER _IOR('t', 137, int) /* Safely open the slave */
/* Little f */
#define FIOCLEX _IO('f', 1)
diff --git a/arch/xtensa/include/uapi/asm/ioctls.h b/arch/xtensa/include/uapi/asm/ioctls.h
index 518954e74e6d..98b004e24e85 100644
--- a/arch/xtensa/include/uapi/asm/ioctls.h
+++ b/arch/xtensa/include/uapi/asm/ioctls.h
@@ -105,6 +105,7 @@
#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */
+#define TIOCGPTPEER _IOR('T', 0x41, int) /* Safely open the slave */
#define TIOCSERCONFIG _IO('T', 83)
#define TIOCSERGWILD _IOR('T', 84, int)
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index 2a6bd9ae3f8b..d1399aac05a1 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -24,6 +24,9 @@
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/poll.h>
+#include <linux/mount.h>
+#include <linux/file.h>
+#include <linux/ioctl.h>
#undef TTY_DEBUG_HANGUP
#ifdef TTY_DEBUG_HANGUP
@@ -66,8 +69,13 @@ static void pty_close(struct tty_struct *tty, struct file *filp)
#ifdef CONFIG_UNIX98_PTYS
if (tty->driver == ptm_driver) {
mutex_lock(&devpts_mutex);
- if (tty->link->driver_data)
- devpts_pty_kill(tty->link->driver_data);
+ if (tty->link->driver_data) {
+ struct path *path = tty->link->driver_data;
+
+ devpts_pty_kill(path->dentry);
+ path_put(path);
+ kfree(path);
+ }
mutex_unlock(&devpts_mutex);
}
#endif
@@ -440,6 +448,48 @@ err:
return retval;
}
+/**
+ * pty_open_peer - open the peer of a pty
+ * @tty: the peer of the pty being opened
+ *
+ * Open the cached dentry in tty->link, providing a safe way for userspace
+ * to get the slave end of a pty (where they have the master fd and cannot
+ * access or trust the mount namespace /dev/pts was mounted inside).
+ */
+static struct file *pty_open_peer(struct tty_struct *tty, int flags)
+{
+ if (tty->driver->subtype != PTY_TYPE_MASTER)
+ return ERR_PTR(-EIO);
+ return dentry_open(tty->link->driver_data, flags, current_cred());
+}
+
+static int pty_get_peer(struct tty_struct *tty, int flags)
+{
+ int fd = -1;
+ struct file *filp = NULL;
+ int retval = -EINVAL;
+
+ fd = get_unused_fd_flags(0);
+ if (fd < 0) {
+ retval = fd;
+ goto err;
+ }
+
+ filp = pty_open_peer(tty, flags);
+ if (IS_ERR(filp)) {
+ retval = PTR_ERR(filp);
+ goto err_put;
+ }
+
+ fd_install(fd, filp);
+ return fd;
+
+err_put:
+ put_unused_fd(fd);
+err:
+ return retval;
+}
+
static void pty_cleanup(struct tty_struct *tty)
{
tty_port_put(tty->port);
@@ -613,6 +663,8 @@ static int pty_unix98_ioctl(struct tty_struct *tty,
return pty_get_pktmode(tty, (int __user *)arg);
case TIOCGPTN: /* Get PT Number */
return put_user(tty->index, (unsigned int __user *)arg);
+ case TIOCGPTPEER: /* Open the other end */
+ return pty_get_peer(tty, (int) arg);
case TIOCSIG: /* Send signal to other side of pty */
return pty_signal(tty, (int) arg);
}
@@ -740,6 +792,7 @@ static int ptmx_open(struct inode *inode, struct file *filp)
{
struct pts_fs_info *fsi;
struct tty_struct *tty;
+ struct path *pts_path;
struct dentry *dentry;
int retval;
int index;
@@ -793,16 +846,26 @@ static int ptmx_open(struct inode *inode, struct file *filp)
retval = PTR_ERR(dentry);
goto err_release;
}
- tty->link->driver_data = dentry;
+ /* We need to cache a fake path for TIOCGPTPEER. */
+ pts_path = kmalloc(sizeof(struct path), GFP_KERNEL);
+ if (!pts_path)
+ goto err_release;
+ pts_path->mnt = filp->f_path.mnt;
+ pts_path->dentry = dentry;
+ path_get(pts_path);
+ tty->link->driver_data = pts_path;
retval = ptm_driver->ops->open(tty, filp);
if (retval)
- goto err_release;
+ goto err_path_put;
tty_debug_hangup(tty, "opening (count=%d)\n", tty->count);
tty_unlock(tty);
return 0;
+err_path_put:
+ path_put(pts_path);
+ kfree(pts_path);
err_release:
tty_unlock(tty);
// This will also put-ref the fsi
diff --git a/include/uapi/asm-generic/ioctls.h b/include/uapi/asm-generic/ioctls.h
index 143dacbb7d9a..06d5f7ddf84e 100644
--- a/include/uapi/asm-generic/ioctls.h
+++ b/include/uapi/asm-generic/ioctls.h
@@ -77,6 +77,7 @@
#define TIOCGPKT _IOR('T', 0x38, int) /* Get packet mode state */
#define TIOCGPTLCK _IOR('T', 0x39, int) /* Get Pty lock state */
#define TIOCGEXCL _IOR('T', 0x40, int) /* Get exclusive mode state */
+#define TIOCGPTPEER _IOR('T', 0x41, int) /* Safely open the slave */
#define FIONCLEX 0x5450
#define FIOCLEX 0x5451
generated by cgit (git 2.34.1) at 2024-05-02 13:31:56 +0000