[PATCH] fs: add basic sanity check before accessing the files array

[Baruch Siach]

Hi Jean-Christophe,

On Tue, Jul 27, 2010 at 03:34:07PM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> 	it will be better to use a common function to do the check

OK. Will do.

baruch

> On 16:16 Tue 27 Jul     , Baruch Siach wrote:
> > This patch adds some basic file descriptor sanity checks to the file access
> > routines. Check whether the given file descriptor is in the files array range,
> > and whether the file entry is valid.
> > 
> > Signed-off-by: Baruch Siach <baruch at tkos.co.il>
> > ---
> >  fs/fs.c |   40 ++++++++++++++++++++++++++++++++++++++++
> >  1 files changed, 40 insertions(+), 0 deletions(-)
> > 
> > diff --git a/fs/fs.c b/fs/fs.c
> > index 8417067..449dcc2 100644
> > --- a/fs/fs.c
> > +++ b/fs/fs.c
> > @@ -457,6 +457,11 @@ int ioctl(int fd, int request, void *buf)
> >  	struct fs_driver_d *fsdrv;
> >  	FILE *f = &files[fd];
> >  
> > +	if (fd < 0 || fd >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return errno;
> > +	}
> > +
> >  	dev = f->dev;
> >  
> >  	fsdrv = (struct fs_driver_d *)dev->driver->type_data;
> > @@ -474,6 +479,11 @@ int read(int fd, void *buf, size_t count)
> >  	struct fs_driver_d *fsdrv;
> >  	FILE *f = &files[fd];
> >  
> > +	if (fd < 0 || fd >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return errno;
> > +	}
> > +
> >  	dev = f->dev;
> >  
> >  	fsdrv = (struct fs_driver_d *)dev->driver->type_data;
> > @@ -494,6 +504,11 @@ ssize_t write(int fd, const void *buf, size_t count)
> >  	struct fs_driver_d *fsdrv;
> >  	FILE *f = &files[fd];
> >  
> > +	if (fd < 0 || fd >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return errno;
> > +	}
> > +
> >  	dev = f->dev;
> >  
> >  	fsdrv = (struct fs_driver_d *)dev->driver->type_data;
> > @@ -524,6 +539,11 @@ off_t lseek(int fildes, off_t offset, int whence)
> >  	FILE *f = &files[fildes];
> >  	off_t pos;
> >  
> > +	if (fildes < 0 || fildes >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return -1;
> > +	}
> > +
> >  	errno = 0;
> >  
> >  	dev = f->dev;
> > @@ -567,6 +587,11 @@ int erase(int fd, size_t count, unsigned long offset)
> >  	struct fs_driver_d *fsdrv;
> >  	FILE *f = &files[fd];
> >  
> > +	if (fd < 0 || fd >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return errno;
> > +	}
> > +
> >  	dev = f->dev;
> >  
> >  	fsdrv = (struct fs_driver_d *)dev->driver->type_data;
> > @@ -589,6 +614,11 @@ int protect(int fd, size_t count, unsigned long offset, int prot)
> >  	struct fs_driver_d *fsdrv;
> >  	FILE *f = &files[fd];
> >  
> > +	if (fd < 0 || fd >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return errno;
> > +	}
> > +
> >  	dev = f->dev;
> >  
> >  	fsdrv = (struct fs_driver_d *)dev->driver->type_data;
> > @@ -627,6 +657,11 @@ void *memmap(int fd, int flags)
> >  	FILE *f = &files[fd];
> >  	void *ret = (void *)-1;
> >  
> > +	if (fd < 0 || fd >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return ret;
> > +	}
> > +
> >  	dev = f->dev;
> >  
> >  	fsdrv = (struct fs_driver_d *)dev->driver->type_data;
> > @@ -646,6 +681,11 @@ int close(int fd)
> >  	struct fs_driver_d *fsdrv;
> >  	FILE *f = &files[fd];
> >  
> > +	if (fd < 0 || fd >= MAX_FILES || !f->in_use) {
> > +		errno = -EBADF;
> > +		return errno;
> > +	}
> > +
> >  	dev = f->dev;
> >  
> >  	fsdrv = (struct fs_driver_d *)dev->driver->type_data;
> > -- 
> > 1.7.1

-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -