From: Seth Forshee <seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> To: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>, Casey Schaufler <casey-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org> Cc: Serge Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>, Seth Forshee <seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>, James Morris <james.l.morris-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Miklos Szeredi <miklos-sUDqSbJrdHQHWmgEVkV9KA@public.gmane.org>, linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, fuse-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, Austin S Hemmelgarn <ahferroin7-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Alexander Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>, selinux-+05T5uksL2qpZYMLLGbcSA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "Serge E. Hallyn" <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org> Subject: [PATCH v2 06/18] Smack: Handle labels consistently in untrusted mounts Date: Mon, 7 Dec 2015 15:21:15 -0600 [thread overview] Message-ID: <1449523289-144238-7-git-send-email-seth.forshee@canonical.com> (raw) In-Reply-To: <1449523289-144238-1-git-send-email-seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> The SMACK64, SMACK64EXEC, and SMACK64MMAP labels are all handled differently in untrusted mounts. This is confusing and potentically problematic. Change this to handle them all the same way that SMACK64 is currently handled; that is, read the label from disk and check it at use time. For SMACK64 and SMACK64MMAP access is denied if the label does not match smk_root. To be consistent with suid, a SMACK64EXEC label which does not match smk_root will still allow execution of the file but will not run with the label supplied in the xattr. Signed-off-by: Seth Forshee <seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> Acked-by: Casey Schaufler <casey-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org> --- security/smack/smack_lsm.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 16cac04214e2..0e555f64ded0 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -921,6 +921,7 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) struct inode *inode = file_inode(bprm->file); struct task_smack *bsp = bprm->cred->security; struct inode_smack *isp; + struct superblock_smack *sbsp; int rc; if (bprm->cred_prepared) @@ -930,6 +931,11 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task) return 0; + sbsp = inode->i_sb->s_security; + if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) && + isp->smk_task != sbsp->smk_root) + return 0; + if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { struct task_struct *tracer; rc = 0; @@ -1733,6 +1739,7 @@ static int smack_mmap_file(struct file *file, struct task_smack *tsp; struct smack_known *okp; struct inode_smack *isp; + struct superblock_smack *sbsp; int may; int mmay; int tmay; @@ -1744,6 +1751,10 @@ static int smack_mmap_file(struct file *file, isp = file_inode(file)->i_security; if (isp->smk_mmap == NULL) return 0; + sbsp = file_inode(file)->i_sb->s_security; + if (sbsp->smk_flags & SMK_SB_UNTRUSTED && + isp->smk_mmap != sbsp->smk_root) + return -EACCES; mkp = isp->smk_mmap; tsp = current_security(); @@ -3532,16 +3543,14 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) if (rc >= 0) transflag = SMK_INODE_TRANSMUTE; } - if (!(sbsp->smk_flags & SMK_SB_UNTRUSTED)) { - /* - * Don't let the exec or mmap label be "*" or "@". - */ - skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); - if (IS_ERR(skp) || skp == &smack_known_star || - skp == &smack_known_web) - skp = NULL; - isp->smk_task = skp; - } + /* + * Don't let the exec or mmap label be "*" or "@". + */ + skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); + if (IS_ERR(skp) || skp == &smack_known_star || + skp == &smack_known_web) + skp = NULL; + isp->smk_task = skp; skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); if (IS_ERR(skp) || skp == &smack_known_star || -- 1.9.1 ------------------------------------------------------------------------------ Go from Idea to Many App Stores Faster with Intel(R) XDK Give your users amazing mobile app experiences with Intel(R) XDK. Use one codebase in this all-in-one HTML5 development environment. Design, debug & build mobile apps & 2D/3D high-impact games for multiple OSs. http://pubads.g.doubleclick.net/gampad/clk?id=254741911&iu=/4140
WARNING: multiple messages have this Message-ID (diff)
From: Seth Forshee <seth.forshee@canonical.com> To: "Eric W. Biederman" <ebiederm@xmission.com>, Casey Schaufler <casey@schaufler-ca.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk>, Serge Hallyn <serge.hallyn@canonical.com>, Richard Weinberger <richard.weinberger@gmail.com>, Austin S Hemmelgarn <ahferroin7@gmail.com>, Miklos Szeredi <miklos@szeredi.hu>, linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, fuse-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, Seth Forshee <seth.forshee@canonical.com>, James Morris <james.l.morris@oracle.com>, "Serge E. Hallyn" <serge@hallyn.com> Subject: [PATCH v2 06/18] Smack: Handle labels consistently in untrusted mounts Date: Mon, 7 Dec 2015 15:21:15 -0600 [thread overview] Message-ID: <1449523289-144238-7-git-send-email-seth.forshee@canonical.com> (raw) In-Reply-To: <1449523289-144238-1-git-send-email-seth.forshee@canonical.com> The SMACK64, SMACK64EXEC, and SMACK64MMAP labels are all handled differently in untrusted mounts. This is confusing and potentically problematic. Change this to handle them all the same way that SMACK64 is currently handled; that is, read the label from disk and check it at use time. For SMACK64 and SMACK64MMAP access is denied if the label does not match smk_root. To be consistent with suid, a SMACK64EXEC label which does not match smk_root will still allow execution of the file but will not run with the label supplied in the xattr. Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> --- security/smack/smack_lsm.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 16cac04214e2..0e555f64ded0 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -921,6 +921,7 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) struct inode *inode = file_inode(bprm->file); struct task_smack *bsp = bprm->cred->security; struct inode_smack *isp; + struct superblock_smack *sbsp; int rc; if (bprm->cred_prepared) @@ -930,6 +931,11 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm) if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task) return 0; + sbsp = inode->i_sb->s_security; + if ((sbsp->smk_flags & SMK_SB_UNTRUSTED) && + isp->smk_task != sbsp->smk_root) + return 0; + if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) { struct task_struct *tracer; rc = 0; @@ -1733,6 +1739,7 @@ static int smack_mmap_file(struct file *file, struct task_smack *tsp; struct smack_known *okp; struct inode_smack *isp; + struct superblock_smack *sbsp; int may; int mmay; int tmay; @@ -1744,6 +1751,10 @@ static int smack_mmap_file(struct file *file, isp = file_inode(file)->i_security; if (isp->smk_mmap == NULL) return 0; + sbsp = file_inode(file)->i_sb->s_security; + if (sbsp->smk_flags & SMK_SB_UNTRUSTED && + isp->smk_mmap != sbsp->smk_root) + return -EACCES; mkp = isp->smk_mmap; tsp = current_security(); @@ -3532,16 +3543,14 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) if (rc >= 0) transflag = SMK_INODE_TRANSMUTE; } - if (!(sbsp->smk_flags & SMK_SB_UNTRUSTED)) { - /* - * Don't let the exec or mmap label be "*" or "@". - */ - skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); - if (IS_ERR(skp) || skp == &smack_known_star || - skp == &smack_known_web) - skp = NULL; - isp->smk_task = skp; - } + /* + * Don't let the exec or mmap label be "*" or "@". + */ + skp = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp); + if (IS_ERR(skp) || skp == &smack_known_star || + skp == &smack_known_web) + skp = NULL; + isp->smk_task = skp; skp = smk_fetch(XATTR_NAME_SMACKMMAP, inode, dp); if (IS_ERR(skp) || skp == &smack_known_star || -- 1.9.1
next prev parent reply other threads:[~2015-12-07 21:21 UTC|newest] Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-12-07 21:21 [PATCH v2 00/19] Support fuse mounts in user namespaces Seth Forshee 2015-12-07 21:21 ` [PATCH v2 03/18] fs: Treat foreign mounts as nosuid Seth Forshee 2015-12-07 21:21 ` [PATCH v2 04/18] selinux: Add support for unprivileged mounts from user namespaces Seth Forshee [not found] ` <1449523289-144238-1-git-send-email-seth.forshee-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org> 2015-12-07 21:21 ` [PATCH v2 01/18] block_dev: Support checking inode permissions in lookup_bdev() Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 02/18] block_dev: Check permissions towards block device inode when mounting Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 05/18] userns: Replace in_userns with current_in_userns Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` Seth Forshee [this message] 2015-12-07 21:21 ` [PATCH v2 06/18] Smack: Handle labels consistently in untrusted mounts Seth Forshee 2015-12-07 21:21 ` [PATCH v2 07/18] fs: Check for invalid i_uid in may_follow_link() Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 08/18] cred: Reject inodes with invalid ids in set_create_file_as() Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 09/18] fs: Refuse uid/gid changes which don't map into s_user_ns Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 10/18] fs: Update posix_acl support to handle user namespace mounts Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 11/18] fs: Ensure the mounter of a filesystem is privileged towards its inodes Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 12/18] fs: Don't remove suid for CAP_FSETID in s_user_ns Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 15/18] fuse: Add support for pid namespaces Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 16/18] fuse: Support fuse filesystems outside of init_user_ns Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 17/18] fuse: Restrict allow_other to the superblock's namespace or a descendant Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 18/18] fuse: Allow user namespace mounts Seth Forshee 2015-12-07 21:21 ` Seth Forshee 2015-12-07 21:21 ` [PATCH v2 13/18] fs: Allow superblock owner to access do_remount_sb() Seth Forshee 2015-12-07 21:21 ` [PATCH v2 14/18] capabilities: Allow privileged user in s_user_ns to set security.* xattrs Seth Forshee
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1449523289-144238-7-git-send-email-seth.forshee@canonical.com \ --to=seth.forshee-z7wlfzj8ewms+fvcfc7uqw@public.gmane.org \ --cc=ahferroin7-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org \ --cc=casey-iSGtlc1asvQWG2LlvL+J4A@public.gmane.org \ --cc=dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org \ --cc=ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org \ --cc=fuse-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org \ --cc=james.l.morris-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org \ --cc=linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org \ --cc=linux-raid-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \ --cc=miklos-sUDqSbJrdHQHWmgEVkV9KA@public.gmane.org \ --cc=selinux-+05T5uksL2qpZYMLLGbcSA@public.gmane.org \ --cc=serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org \ --cc=serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org \ --cc=viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.