[PATCH v2 6/7] ima: Discard files opened with O_PATH

[Roberto Sassu]

On Thu, 2024-11-28 at 17:22 +0100, Christian Brauner wrote:
> On Thu, Nov 28, 2024 at 11:06:19AM +0100, Roberto Sassu wrote:
> > From: Roberto Sassu <roberto.sassu at huawei.com>
> > 
> > According to man open.2, files opened with O_PATH are not really opened. The
> > obtained file descriptor is used to indicate a location in the filesystem
> > tree and to perform operations that act purely at the file descriptor
> > level.
> > 
> > Thus, ignore open() syscalls with O_PATH, since IMA cares about file data.
> > 
> > Cc: stable at vger.kernel.org # v2.6.39.x
> > Fixes: 1abf0c718f15a ("New kind of open files - "location only".")
> > Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
> > ---
> >  security/integrity/ima/ima_main.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> > index 50b37420ea2c..712c3a522e6c 100644
> > --- a/security/integrity/ima/ima_main.c
> > +++ b/security/integrity/ima/ima_main.c
> > @@ -202,7 +202,8 @@ static void ima_file_free(struct file *file)
> >  	struct inode *inode = file_inode(file);
> >  	struct ima_iint_cache *iint;
> >  
> > -	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
> > +	if (!ima_policy_flag || !S_ISREG(inode->i_mode) ||
> > +	    (file->f_flags & O_PATH))
> >  		return;
> >  
> >  	iint = ima_iint_find(inode);
> > @@ -232,7 +233,8 @@ static int process_measurement(struct file *file, const struct cred *cred,
> >  	enum hash_algo hash_algo;
> >  	unsigned int allowed_algos = 0;
> >  
> > -	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
> > +	if (!ima_policy_flag || !S_ISREG(inode->i_mode) ||
> > +	    (file->f_flags & O_PATH))
> >  		return 0;
> 
> if (file->f_mode & FMODE_PATH)
> 
> please.

Oh, ok.

Thanks

Roberto