The patch titled
userns: userns: check user namespace for task->file uid equivalence checks
has been removed from the -mm tree. Its filename was
userns-userns-check-user-namespace-for-task-file-uid-equivalence-checks.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: userns: userns: check user namespace for task->file uid equivalence checks
From: "Serge E. Hallyn" <serge@xxxxxxxxxx>
Cheat for now and say all files belong to init_user_ns. Next step will be
to let superblocks belong to a user_ns, and derive inode_userns(inode)
from inode->i_sb->s_user_ns. Finally we'll introduce more flexible
arrangements.
Changelog:
Feb 15: make is_owner_or_cap take const struct inode
Feb 23: make is_owner_or_cap bool
[akpm@xxxxxxxxxxxxxxxxxxxx: coding-style fixes]
Signed-off-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Acked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxx>
Acked-by: David Howells <dhowells@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/inode.c | 17 +++++++++++++++++
fs/namei.c | 21 ++++++++++++++++-----
include/linux/fs.h | 9 +++++++--
3 files changed, 40 insertions(+), 7 deletions(-)
diff -puN fs/inode.c~userns-userns-check-user-namespace-for-task-file-uid-equivalence-checks fs/inode.c
--- a/fs/inode.c~userns-userns-check-user-namespace-for-task-file-uid-equivalence-checks
+++ a/fs/inode.c
@@ -25,6 +25,7 @@
#include <linux/async.h>
#include <linux/posix_acl.h>
#include <linux/ima.h>
+#include <linux/cred.h>
/*
* This is needed for the following functions:
@@ -1733,3 +1734,19 @@ void inode_init_owner(struct inode *inod
inode->i_mode = mode;
}
EXPORT_SYMBOL(inode_init_owner);
+
+/*
+ * return true if current either has CAP_FOWNER to the
+ * file, or owns the file.
+ */
+bool is_owner_or_cap(const struct inode *inode)
+{
+ struct user_namespace *ns = inode_userns(inode);
+
+ if (current_user_ns() == ns && current_fsuid() == inode->i_uid)
+ return true;
+ if (ns_capable(ns, CAP_FOWNER))
+ return true;
+ return false;
+}
+EXPORT_SYMBOL(is_owner_or_cap);
diff -puN fs/namei.c~userns-userns-check-user-namespace-for-task-file-uid-equivalence-checks fs/namei.c
--- a/fs/namei.c~userns-userns-check-user-namespace-for-task-file-uid-equivalence-checks
+++ a/fs/namei.c
@@ -183,6 +183,9 @@ static int acl_permission_check(struct i
mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
+ if (current_user_ns() != inode_userns(inode))
+ goto other_perms;
+
if (current_fsuid() == inode->i_uid)
mode >>= 6;
else {
@@ -196,6 +199,7 @@ static int acl_permission_check(struct i
mode >>= 3;
}
+other_perms:
/*
* If the DACs are ok we don't need any capability check.
*/
@@ -237,7 +241,7 @@ int generic_permission(struct inode *ino
* Executable DACs are overridable if at least one exec bit is set.
*/
if (!(mask & MAY_EXEC) || execute_ok(inode))
- if (capable(CAP_DAC_OVERRIDE))
+ if (ns_capable(inode_userns(inode), CAP_DAC_OVERRIDE))
return 0;
/*
@@ -245,7 +249,7 @@ int generic_permission(struct inode *ino
*/
mask &= MAY_READ | MAY_WRITE | MAY_EXEC;
if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
- if (capable(CAP_DAC_READ_SEARCH))
+ if (ns_capable(inode_userns(inode), CAP_DAC_READ_SEARCH))
return 0;
return -EACCES;
@@ -654,6 +658,7 @@ static inline int handle_reval_path(stru
static inline int exec_permission(struct inode *inode, unsigned int flags)
{
int ret;
+ struct user_namespace *ns = inode_userns(inode);
if (inode->i_op->permission) {
ret = inode->i_op->permission(inode, MAY_EXEC, flags);
@@ -666,7 +671,8 @@ static inline int exec_permission(struct
if (ret == -ECHILD)
return ret;
- if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH))
+ if (ns_capable(ns, CAP_DAC_OVERRIDE) ||
+ ns_capable(ns, CAP_DAC_READ_SEARCH))
goto ok;
return ret;
@@ -1842,11 +1848,15 @@ static inline int check_sticky(struct in
if (!(dir->i_mode & S_ISVTX))
return 0;
+ if (current_user_ns() != inode_userns(inode))
+ goto other_userns;
if (inode->i_uid == fsuid)
return 0;
if (dir->i_uid == fsuid)
return 0;
- return !capable(CAP_FOWNER);
+
+other_userns:
+ return !ns_capable(inode_userns(inode), CAP_FOWNER);
}
/*
@@ -2440,7 +2450,8 @@ int vfs_mknod(struct inode *dir, struct
if (error)
return error;
- if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD))
+ if ((S_ISCHR(mode) || S_ISBLK(mode)) &&
+ !ns_capable(inode_userns(dir), CAP_MKNOD))
return -EPERM;
if (!dir->i_op->mknod)
diff -puN include/linux/fs.h~userns-userns-check-user-namespace-for-task-file-uid-equivalence-checks include/linux/fs.h
--- a/include/linux/fs.h~userns-userns-check-user-namespace-for-task-file-uid-equivalence-checks
+++ a/include/linux/fs.h
@@ -1457,8 +1457,13 @@ enum {
#define put_fs_excl() atomic_dec(¤t->fs_excl)
#define has_fs_excl() atomic_read(¤t->fs_excl)
-#define is_owner_or_cap(inode) \
- ((current_fsuid() == (inode)->i_uid) || capable(CAP_FOWNER))
+/*
+ * until VFS tracks user namespaces for inodes, just make all files
+ * belong to init_user_ns
+ */
+extern struct user_namespace init_user_ns;
+#define inode_userns(inode) (&init_user_ns)
+extern bool is_owner_or_cap(const struct inode *inode);
/* not quite ready to be deprecated, but... */
extern void lock_super(struct super_block *);
_
Patches currently in -mm which might be from serge@xxxxxxxxxx are
origin.patch
lib-hexdumpc-make-hex2bin-return-the-updated-src-address.patch
fs-binfmt_miscc-use-kernels-hex_to_bin-method.patch
fs-binfmt_miscc-use-kernels-hex_to_bin-method-fix.patch
fs-binfmt_miscc-use-kernels-hex_to_bin-method-fix-fix.patch
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