From: Tomas Bortoli <tomasbortoli@xxxxxxxxx> Subject: autofs: fix slab out of bounds read in getname_kernel() 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@xxxxxxxxxxxxxxxx Signed-off-by: Tomas Bortoli <tomasbortoli@xxxxxxxxx> Signed-off-by: Ian Kent <raven@xxxxxxxxxx> Reported-by: syzbot+60c837b428dc84e83a93@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/autofs/dev-ioctl.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff -puN fs/autofs/dev-ioctl.c~autofs-fix-slab-out-of-bounds-read-in-getname_kernel fs/autofs/dev-ioctl.c --- a/fs/autofs/dev-ioctl.c~autofs-fix-slab-out-of-bounds-read-in-getname_kernel +++ a/fs/autofs/dev-ioctl.c @@ -135,6 +135,15 @@ static int validate_dev_ioctl(int cmd, s 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(st 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(st 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 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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
