From: "Serge E. Hallyn" <serge@hallyn.com> To: Mimi Zohar <zohar@linux.vnet.ibm.com> Cc: linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, Miklos Szeredi <miklos@szeredi.hu>, Seth Forshee <seth.forshee@canonical.com>, "Eric W . Biederman" <ebiederm@xmission.com>, Dongsu Park <dongsu@kinvolk.io>, Alban Crequy <alban@kinvolk.io>, "Serge E . Hallyn" <serge@hallyn.com> Subject: Re: [PATCH v3 2/4] ima: re-evaluate files on privileged mounted filesystems Date: Mon, 12 Mar 2018 14:18:52 -0500 [thread overview] Message-ID: <20180312191852.GB29878@mail.hallyn.com> (raw) In-Reply-To: <1520540650-7451-3-git-send-email-zohar@linux.vnet.ibm.com> Quoting Mimi Zohar (zohar@linux.vnet.ibm.com): > This patch addresses the fuse privileged mounted filesystems in a "secure" > environment, with a correctly enforced security policy, which is willing > to assume the inherent risk of specific fuse filesystems that are well > defined and properly implemented. > > As there is no way for the kernel to detect file changes, the kernel > ignores the cached file integrity results and re-measures, re-appraises, > and re-audits the file. > > Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> > Cc: Miklos Szeredi <miklos@szeredi.hu> > Cc: Seth Forshee <seth.forshee@canonical.com> > Cc: Eric W. Biederman <ebiederm@xmission.com> > Cc: Dongsu Park <dongsu@kinvolk.io> > Cc: Alban Crequy <alban@kinvolk.io> > Cc: Serge E. Hallyn <serge@hallyn.com> Acked-by: Serge Hallyn <serge@hallyn.com> > --- > security/integrity/ima/ima_main.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index a5d225ffc388..f550f25294a3 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -25,6 +25,7 @@ > #include <linux/xattr.h> > #include <linux/ima.h> > #include <linux/iversion.h> > +#include <linux/fs.h> > > #include "ima.h" > > @@ -230,9 +231,17 @@ static int process_measurement(struct file *file, const struct cred *cred, > IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK | > IMA_ACTION_FLAGS); > > - if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags)) > - /* reset all flags if ima_inode_setxattr was called */ > + /* > + * Re-evaulate the file if either the xattr has changed or the > + * kernel has no way of detecting file change on the filesystem. > + * (Limited to privileged mounted filesystems.) > + */ > + if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) || > + ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) && > + !(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER))) { > iint->flags &= ~IMA_DONE_MASK; > + iint->measured_pcrs = 0; > + } > > /* Determine if already appraised/measured based on bitmask > * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED, > -- > 2.7.5
WARNING: multiple messages have this Message-ID (diff)
From: serge@hallyn.com (Serge E. Hallyn) To: linux-security-module@vger.kernel.org Subject: [PATCH v3 2/4] ima: re-evaluate files on privileged mounted filesystems Date: Mon, 12 Mar 2018 14:18:52 -0500 [thread overview] Message-ID: <20180312191852.GB29878@mail.hallyn.com> (raw) In-Reply-To: <1520540650-7451-3-git-send-email-zohar@linux.vnet.ibm.com> Quoting Mimi Zohar (zohar at linux.vnet.ibm.com): > This patch addresses the fuse privileged mounted filesystems in a "secure" > environment, with a correctly enforced security policy, which is willing > to assume the inherent risk of specific fuse filesystems that are well > defined and properly implemented. > > As there is no way for the kernel to detect file changes, the kernel > ignores the cached file integrity results and re-measures, re-appraises, > and re-audits the file. > > Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> > Cc: Miklos Szeredi <miklos@szeredi.hu> > Cc: Seth Forshee <seth.forshee@canonical.com> > Cc: Eric W. Biederman <ebiederm@xmission.com> > Cc: Dongsu Park <dongsu@kinvolk.io> > Cc: Alban Crequy <alban@kinvolk.io> > Cc: Serge E. Hallyn <serge@hallyn.com> Acked-by: Serge Hallyn <serge@hallyn.com> > --- > security/integrity/ima/ima_main.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index a5d225ffc388..f550f25294a3 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -25,6 +25,7 @@ > #include <linux/xattr.h> > #include <linux/ima.h> > #include <linux/iversion.h> > +#include <linux/fs.h> > > #include "ima.h" > > @@ -230,9 +231,17 @@ static int process_measurement(struct file *file, const struct cred *cred, > IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK | > IMA_ACTION_FLAGS); > > - if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags)) > - /* reset all flags if ima_inode_setxattr was called */ > + /* > + * Re-evaulate the file if either the xattr has changed or the > + * kernel has no way of detecting file change on the filesystem. > + * (Limited to privileged mounted filesystems.) > + */ > + if (test_and_clear_bit(IMA_CHANGE_XATTR, &iint->atomic_flags) || > + ((inode->i_sb->s_iflags & SB_I_IMA_UNVERIFIABLE_SIGNATURE) && > + !(inode->i_sb->s_iflags & SB_I_UNTRUSTED_MOUNTER))) { > iint->flags &= ~IMA_DONE_MASK; > + iint->measured_pcrs = 0; > + } > > /* Determine if already appraised/measured based on bitmask > * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED, > -- > 2.7.5 -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2018-03-12 19:18 UTC|newest] Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-03-08 20:24 [PATCH v3 0/4] unverifiable file signatures Mimi Zohar 2018-03-08 20:24 ` Mimi Zohar 2018-03-08 20:24 ` [PATCH v3 1/4] ima: fail file signature verification on non-init mounted filesystems Mimi Zohar 2018-03-08 20:24 ` Mimi Zohar 2018-03-12 19:17 ` Serge E. Hallyn 2018-03-12 19:17 ` Serge E. Hallyn 2018-03-12 19:26 ` Serge E. Hallyn 2018-03-12 19:26 ` Serge E. Hallyn 2018-03-13 18:45 ` Eric W. Biederman 2018-03-13 18:45 ` Eric W. Biederman 2018-03-08 20:24 ` [PATCH v3 2/4] ima: re-evaluate files on privileged " Mimi Zohar 2018-03-08 20:24 ` Mimi Zohar 2018-03-12 19:18 ` Serge E. Hallyn [this message] 2018-03-12 19:18 ` Serge E. Hallyn 2018-03-13 19:24 ` Eric W. Biederman 2018-03-13 19:24 ` Eric W. Biederman 2018-03-08 20:24 ` [PATCH v3 3/4] ima: fail signature verification based on policy Mimi Zohar 2018-03-08 20:24 ` Mimi Zohar 2018-03-12 19:28 ` Serge E. Hallyn 2018-03-12 19:28 ` Serge E. Hallyn 2018-03-12 19:32 ` Mimi Zohar 2018-03-12 19:32 ` Mimi Zohar 2018-03-13 19:31 ` Eric W. Biederman 2018-03-13 19:31 ` Eric W. Biederman 2018-03-08 20:24 ` [PATCH v3 4/4] fuse: define the filesystem as untrusted Mimi Zohar 2018-03-08 20:24 ` Mimi Zohar 2018-03-12 19:29 ` Serge E. Hallyn 2018-03-12 19:29 ` Serge E. Hallyn 2018-03-13 14:46 ` Stefan Berger 2018-03-13 14:46 ` Stefan Berger 2018-03-14 14:27 ` Serge E. Hallyn 2018-03-14 14:27 ` Serge E. Hallyn 2018-03-14 14:37 ` Stefan Berger 2018-03-14 14:37 ` Stefan Berger 2018-03-13 19:32 ` Eric W. Biederman 2018-03-13 19:32 ` Eric W. Biederman 2018-03-19 11:57 ` Mimi Zohar 2018-03-19 11:57 ` Mimi Zohar 2018-03-19 11:57 ` Mimi Zohar 2018-03-14 7:52 ` Stef Bon 2018-03-14 7:52 ` Stef Bon 2018-03-14 13:01 ` Mimi Zohar 2018-03-14 13:01 ` Mimi Zohar 2018-03-14 16:17 ` Eric W. Biederman 2018-03-14 16:17 ` Eric W. Biederman 2018-03-14 17:50 ` Mimi Zohar 2018-03-14 17:50 ` Mimi Zohar 2018-03-14 17:50 ` Mimi Zohar 2018-03-14 18:08 ` Chuck Lever 2018-03-14 18:08 ` Chuck Lever 2018-03-14 19:46 ` Eric W. Biederman 2018-03-14 19:46 ` Eric W. Biederman 2018-03-14 20:34 ` Chuck Lever 2018-03-14 20:34 ` Chuck Lever 2018-03-14 21:42 ` Eric W. Biederman 2018-03-14 21:42 ` Eric W. Biederman 2018-03-14 22:53 ` Michael Halcrow 2018-03-14 22:53 ` Michael Halcrow 2018-03-15 21:24 ` Mimi Zohar 2018-03-15 21:24 ` Mimi Zohar 2018-03-15 21:24 ` Mimi Zohar 2018-03-15 10:07 ` Stef Bon 2018-03-15 10:07 ` Stef Bon 2018-03-15 13:53 ` Chuck Lever 2018-03-15 13:53 ` Chuck Lever 2018-03-15 22:05 ` Mimi Zohar 2018-03-15 22:05 ` Mimi Zohar 2018-03-13 19:40 ` [PATCH v3 0/4] unverifiable file signatures Eric W. Biederman 2018-03-13 19:40 ` Eric W. Biederman 2018-03-13 20:40 ` Mimi Zohar 2018-03-13 20:40 ` Mimi Zohar
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