autofs: fix slab out of bounds read in getname_kernel() (02f51d45) · Commits · 戴 / test

The autofs subsystem does not check that the "path" parameter is present for all cases where it is required when it is passed in via the "param" struct. In particular it isn't checked for the AUTOFS_DEV_IOCTL_OPENMOUNT_CMD ioctl command. To solve it, modify validate_dev_ioctl(function to check that a path has been provided for ioctl commands that require it. Link: http://lkml.kernel.org/r/153060031527.26631.18306637892746301555.stgit@pluto.themaw.net Signed-off-by:

Tomas Bortoli <tomasbortoli@gmail.com> Signed-off-by:

Ian Kent <raven@themaw.net> Reported-by:

<syzbot+60c837b428dc84e83a93@syzkaller.appspotmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs/dev-ioctl.c

+13 −9

Original line number	Diff line number	Diff line
		@@ -135,6 +135,15 @@ static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
		cmd);
		goto out;
		}
		} else {
		unsigned int inr = _IOC_NR(cmd);

		if (inr == AUTOFS_DEV_IOCTL_OPENMOUNT_CMD \|\|
		inr == AUTOFS_DEV_IOCTL_REQUESTER_CMD \|\|
		inr == AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD) {
		err = -EINVAL;
		goto out;
		}
		}

		err = 0;
		@@ -271,7 +280,8 @@ static int autofs_dev_ioctl_openmount(struct file *fp,
		dev_t devid;
		int err, fd;

		/* param->path has already been checked */
		/* param->path has been checked in validate_dev_ioctl() */

		if (!param->openmount.devid)
		return -EINVAL;

		@@ -433,10 +443,7 @@ static int autofs_dev_ioctl_requester(struct file *fp,
		dev_t devid;
		int err = -ENOENT;

		if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
		err = -EINVAL;
		goto out;
		}
		/* param->path has been checked in validate_dev_ioctl() */

		devid = sbi->sb->s_dev;

		@@ -521,10 +528,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,
		unsigned int devid, magic;
		int err = -ENOENT;

		if (param->size <= AUTOFS_DEV_IOCTL_SIZE) {
		err = -EINVAL;
		goto out;
		}
		/* param->path has been checked in validate_dev_ioctl() */

		name = param->path;
		type = param->ismountpoint.in.type;

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