From: Aleksa Sarai <cyphar@cyphar.com>
To: Al Viro <viro@zeniv.linux.org.uk>,
Jeff Layton <jlayton@kernel.org>,
"J. Bruce Fields" <bfields@fieldses.org>,
Arnd Bergmann <arnd@arndb.de>,
David Howells <dhowells@redhat.com>,
Shuah Khan <shuah@kernel.org>,
Shuah Khan <skhan@linuxfoundation.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>,
Eric Biederman <ebiederm@xmission.com>,
Andy Lutomirski <luto@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>,
Tycho Andersen <tycho@tycho.ws>,
David Drysdale <drysdale@google.com>,
Chanho Min <chanho.min@lge.com>, Oleg Nesterov <oleg@redhat.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Christian Brauner <christian@brauner.io>,
Aleksa Sarai <asarai@suse.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
dev@opencontainers.org, containers@lists.linux-foundation.org,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-alpha@vger.kernel.org, linux-api@vger.kernel.org,
libc-alpha@sourceware.org, linux-arch@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, linux-sh@vger.kernel.org,
linux-xtensa@linux-xtensa.org, sparclinux@vger.kernel.org
Subject: [PATCH v16 02/12] namei: allow nd_jump_link() to produce errors
Date: Sat, 16 Nov 2019 11:27:52 +1100 [thread overview]
Message-ID: <20191116002802.6663-3-cyphar@cyphar.com> (raw)
Message-ID: <20191116002752.5mEYn2jYNYZDs5GWi7zeD9VEqF5q4AlBg403y2_yNYU@z> (raw)
In-Reply-To: <20191116002802.6663-1-cyphar@cyphar.com>
In preparation for LOOKUP_NO_MAGICLINKS, it's necessary to add the
ability for nd_jump_link() to return an error which the corresponding
get_link() caller must propogate back up to the VFS.
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
fs/namei.c | 3 ++-
fs/proc/base.c | 5 +++--
fs/proc/namespaces.c | 17 ++++++++++++-----
include/linux/namei.h | 2 +-
security/apparmor/apparmorfs.c | 8 ++++++--
5 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 671c3c1a3425..965a25b2e3df 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -859,7 +859,7 @@ static int nd_jump_root(struct nameidata *nd)
* Helper to directly jump to a known parsed path from ->get_link,
* caller must have taken a reference to path beforehand.
*/
-void nd_jump_link(struct path *path)
+int nd_jump_link(struct path *path)
{
struct nameidata *nd = current->nameidata;
path_put(&nd->path);
@@ -867,6 +867,7 @@ void nd_jump_link(struct path *path)
nd->path = *path;
nd->inode = nd->path.dentry->d_inode;
nd->flags |= LOOKUP_JUMPED;
+ return 0;
}
static inline void put_link(struct nameidata *nd)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index ebea9501afb8..fecd5b4af607 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1626,8 +1626,9 @@ static const char *proc_pid_get_link(struct dentry *dentry,
if (error)
goto out;
- nd_jump_link(&path);
- return NULL;
+ error = nd_jump_link(&path);
+ if (error)
+ path_put(&path);
out:
return ERR_PTR(error);
}
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index 08dd94df1a66..95e199fbad57 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -51,11 +51,18 @@ static const char *proc_ns_get_link(struct dentry *dentry,
if (!task)
return ERR_PTR(-EACCES);
- if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
- error = ns_get_path(&ns_path, task, ns_ops);
- if (!error)
- nd_jump_link(&ns_path);
- }
+ if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
+ goto out;
+
+ error = ns_get_path(&ns_path, task, ns_ops);
+ if (error)
+ goto out;
+
+ error = nd_jump_link(&ns_path);
+ if (error)
+ path_put(&ns_path);
+
+out:
put_task_struct(task);
return ERR_PTR(error);
}
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 397a08ade6a2..758e9b47db6f 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -68,7 +68,7 @@ extern int follow_up(struct path *);
extern struct dentry *lock_rename(struct dentry *, struct dentry *);
extern void unlock_rename(struct dentry *, struct dentry *);
-extern void nd_jump_link(struct path *path);
+extern int __must_check nd_jump_link(struct path *path);
static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
{
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index 45d13b6462aa..da045d0477a5 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -2455,16 +2455,20 @@ static const char *policy_get_link(struct dentry *dentry,
{
struct aa_ns *ns;
struct path path;
+ int error;
if (!dentry)
return ERR_PTR(-ECHILD);
+
ns = aa_get_current_ns();
path.mnt = mntget(aafs_mnt);
path.dentry = dget(ns_dir(ns));
- nd_jump_link(&path);
+ error = nd_jump_link(&path);
+ if (error)
+ path_put(&path);
aa_put_ns(ns);
- return NULL;
+ return ERR_PTR(error);
}
static int policy_readlink(struct dentry *dentry, char __user *buffer,
--
2.24.0
next prev parent reply other threads:[~2019-11-16 0:29 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-16 0:27 [PATCH v16 00/12] open: introduce openat2(2) syscall Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 01/12] nsfs: clean-up ns_get_path() signature to return int Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai [this message]
2019-11-16 0:27 ` [PATCH v16 02/12] namei: allow nd_jump_link() to produce errors Aleksa Sarai
2019-11-16 0:37 ` Al Viro
2019-11-16 0:37 ` Al Viro
2019-11-16 18:09 ` Aleksa Sarai
2019-11-16 18:09 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 03/12] namei: allow set_root() " Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 04/12] namei: LOOKUP_NO_SYMLINKS: block symlink resolution Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 05/12] namei: LOOKUP_NO_MAGICLINKS: block magic-link resolution Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 06/12] namei: LOOKUP_NO_XDEV: block mountpoint crossing Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 07/12] namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 08/12] namei: LOOKUP_IN_ROOT: chroot-like " Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:27 ` [PATCH v16 09/12] namei: LOOKUP_{IN_ROOT,BENEATH}: permit limited ".." resolution Aleksa Sarai
2019-11-16 0:27 ` Aleksa Sarai
2019-11-16 0:28 ` [PATCH v16 10/12] open: introduce openat2(2) syscall Aleksa Sarai
2019-11-16 0:28 ` Aleksa Sarai
2019-11-16 0:28 ` [PATCH v16 11/12] selftests: add openat2(2) selftests Aleksa Sarai
2019-11-16 0:28 ` Aleksa Sarai
2019-11-16 0:28 ` [PATCH v16 12/12] Documentation: path-lookup: include new LOOKUP flags Aleksa Sarai
2019-11-16 0:28 ` Aleksa Sarai
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