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SubjectRe: [PATCH] ima: use full pathnames in measurement list
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On Wed, 2012-06-27 at 14:18 +0300, Kasatkin, Dmitry wrote:
> On Mon, Jun 25, 2012 at 1:45 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
> > On Mon, 2012-06-25 at 12:29 +1000, James Morris wrote:
> >> On Fri, 22 Jun 2012, Mimi Zohar wrote:
> >>
> >> > The IMA measurement list contains filename hints, which can be
> >> > ambigious without the full pathname. This patch replaces the
> >> > filename hint with the full pathname, simplifying for userspace
> >> > the correlating of file hash measurements with files.
> >> >
> >> > Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
> >>
> >> Are you posting this for review or do you want it applied to my tree?
> >
> > It was posted for review, but both are good.
> >
> > thanks,
> >
> > Mimi
> >
> >> > ---
> >> > security/integrity/ima/ima_main.c | 40 +++++++++++++++++++++++++++++++-----
> >> > 1 files changed, 34 insertions(+), 6 deletions(-)
> >> >
> >> > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> >> > index b17be79..91fa323 100644
> >> > --- a/security/integrity/ima/ima_main.c
> >> > +++ b/security/integrity/ima/ima_main.c
> >> > @@ -54,6 +54,7 @@ static void ima_rdwr_violation_check(struct file *file)
> >> > fmode_t mode = file->f_mode;
> >> > int rc;
> >> > bool send_tomtou = false, send_writers = false;
> >> > + unsigned char *pathname = NULL, *pathbuf = NULL;
> >> >
> >> > if (!S_ISREG(inode->i_mode) || !ima_initialized)
> >> > return;
> >> > @@ -75,12 +76,25 @@ static void ima_rdwr_violation_check(struct file *file)
> >> > out:
> >> > mutex_unlock(&inode->i_mutex);
> >> >
> >> > + if (!send_tomtou && !send_writers)
> >> > + return;
> >> > +
> >> > + /* We will allow 11 spaces for ' (deleted)' to be appended */
> >> > + pathbuf = kmalloc(PATH_MAX + 11, GFP_KERNEL);
> >> > + if (pathbuf) {
> >> > + pathname = d_path(&file->f_path, pathbuf, PATH_MAX + 11);
> >> > + if (IS_ERR(pathname))
> >> > + pathname = NULL;
> >> > + }
> >> > if (send_tomtou)
> >> > - ima_add_violation(inode, dentry->d_name.name, "invalid_pcr",
> >> > - "ToMToU");
> >> > + ima_add_violation(inode,
> >> > + !pathname ? dentry->d_name.name : pathname,
> >> > + "invalid_pcr", "ToMToU");
> >> > if (send_writers)
> >> > - ima_add_violation(inode, dentry->d_name.name, "invalid_pcr",
> >> > - "open_writers");
> >> > + ima_add_violation(inode,
> >> > + !pathname ? dentry->d_name.name : pathname,
> >> > + "invalid_pcr", "open_writers");
> >> > + kfree(pathbuf);
> >> > }
> >> >
> >> > static void ima_check_last_writer(struct integrity_iint_cache *iint,
> >> > @@ -123,6 +137,7 @@ static int process_measurement(struct file *file, const unsigned char *filename,
> >> > {
> >> > struct inode *inode = file->f_dentry->d_inode;
> >> > struct integrity_iint_cache *iint;
> >> > + unsigned char *pathname = NULL, *pathbuf = NULL;
> >> > int rc = 0;
> >> >
> >> > if (!ima_initialized || !S_ISREG(inode->i_mode))
> >> > @@ -147,8 +162,21 @@ retry:
> >> > goto out;
> >> >
> >> > rc = ima_collect_measurement(iint, file);
> >> > - if (!rc)
> >> > - ima_store_measurement(iint, file, filename);
> >> > + if (rc != 0)
> >> > + goto out;
> >> > +
> >> > + if (function != BPRM_CHECK) {
> >> > + /* We will allow 11 spaces for ' (deleted)' to be appended */
> >> > + pathbuf = kmalloc(PATH_MAX + 11, GFP_KERNEL);
> >> > + if (pathbuf) {
> >> > + pathname =
> >> > + d_path(&file->f_path, pathbuf, PATH_MAX + 11);
> >> > + if (IS_ERR(pathname))
> >> > + pathname = NULL;
> >> > + }
> >> > + }
> >> > + ima_store_measurement(iint, file, !pathname ? filename : pathname);
>
>
> ima_store_measurement() has such line:
>
> strncpy(entry->template.file_name, filename, IMA_EVENT_NAME_LEN_MAX);
>
> It might happens to copy beginning of the path....
>
> - Dmitry

Yes, for now I'll add a string check, but it's time to resurrect the
template patches, which add support for different hashes and other file
metadata, and support variable length records.

Mimi



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