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Open Source and information security mailing list archives
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Date: Tue, 12 Jan 2021 23:01:12 +0100 From: Christian Brauner <christian.brauner@...ntu.com> To: Alexander Viro <viro@...iv.linux.org.uk>, Christoph Hellwig <hch@...radead.org>, linux-fsdevel@...r.kernel.org Cc: John Johansen <john.johansen@...onical.com>, James Morris <jmorris@...ei.org>, Mimi Zohar <zohar@...ux.ibm.com>, Dmitry Kasatkin <dmitry.kasatkin@...il.com>, Stephen Smalley <stephen.smalley.work@...il.com>, Casey Schaufler <casey@...aufler-ca.com>, Arnd Bergmann <arnd@...db.de>, Andreas Dilger <adilger.kernel@...ger.ca>, OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>, Geoffrey Thomas <geofft@...reload.com>, Mrunal Patel <mpatel@...hat.com>, Josh Triplett <josh@...htriplett.org>, Andy Lutomirski <luto@...nel.org>, Theodore Tso <tytso@....edu>, Alban Crequy <alban@...volk.io>, Tycho Andersen <tycho@...ho.ws>, David Howells <dhowells@...hat.com>, James Bottomley <James.Bottomley@...senpartnership.com>, Seth Forshee <seth.forshee@...onical.com>, Stéphane Graber <stgraber@...ntu.com>, Linus Torvalds <torvalds@...ux-foundation.org>, Aleksa Sarai <cyphar@...har.com>, Lennart Poettering <lennart@...ttering.net>, "Eric W. Biederman" <ebiederm@...ssion.com>, smbarber@...omium.org, Phil Estes <estesp@...il.com>, Serge Hallyn <serge@...lyn.com>, Kees Cook <keescook@...omium.org>, Todd Kjos <tkjos@...gle.com>, Paul Moore <paul@...l-moore.com>, Jonathan Corbet <corbet@....net>, containers@...ts.linux-foundation.org, linux-security-module@...r.kernel.org, linux-api@...r.kernel.org, linux-ext4@...r.kernel.org, linux-xfs@...r.kernel.org, linux-integrity@...r.kernel.org, selinux@...r.kernel.org, Christian Brauner <christian.brauner@...ntu.com>, Christoph Hellwig <hch@....de> Subject: [PATCH v5 30/42] would_dump: handle idmapped mounts When determining whether or not to create a coredump the vfs will verify that the caller is privileged over the inode. Make the would_dump() helper handle idmapped mounts by passing down the mount's user namespace of the exec file. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Cc: Christoph Hellwig <hch@....de> Cc: David Howells <dhowells@...hat.com> Cc: Al Viro <viro@...iv.linux.org.uk> Cc: linux-fsdevel@...r.kernel.org Signed-off-by: Christian Brauner <christian.brauner@...ntu.com> --- /* v2 */ unchanged /* v3 */ unchanged /* v4 */ - Serge Hallyn <serge@...lyn.com>: - Use "mnt_userns" to refer to a vfsmount's userns everywhere to make terminology consistent. /* v5 */ base-commit: 7c53f6b671f4aba70ff15e1b05148b10d58c2837 - Christoph Hellwig <hch@....de>: - Use new file_userns_helper(). --- fs/exec.c | 5 +++-- fs/fcntl.c | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 049a8d2669db..36a1b927a8ae 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1404,14 +1404,15 @@ EXPORT_SYMBOL(begin_new_exec); void would_dump(struct linux_binprm *bprm, struct file *file) { struct inode *inode = file_inode(file); - if (inode_permission(&init_user_ns, inode, MAY_READ) < 0) { + struct user_namespace *mnt_userns = file_user_ns(file); + if (inode_permission(mnt_userns, inode, MAY_READ) < 0) { struct user_namespace *old, *user_ns; bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; /* Ensure mm->user_ns contains the executable */ user_ns = old = bprm->mm->user_ns; while ((user_ns != &init_user_ns) && - !privileged_wrt_inode_uidgid(user_ns, &init_user_ns, inode)) + !privileged_wrt_inode_uidgid(user_ns, mnt_userns, inode)) user_ns = user_ns->parent; if (old != user_ns) { diff --git a/fs/fcntl.c b/fs/fcntl.c index 58706031e603..ebbe831d5736 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -47,7 +47,7 @@ static int setfl(int fd, struct file * filp, unsigned long arg) /* O_NOATIME can only be set by the owner or superuser */ if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) - if (!inode_owner_or_capable(mnt_user_ns(filp->f_path.mnt), inode)) + if (!inode_owner_or_capable(file_user_ns(filp), inode)) return -EPERM; /* required for strict SunOS emulation */ -- 2.30.0
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