From: "Luis R. Rodriguez" <mcgrof@xxxxxxxxxxxxxxxx>
Commit adb37c4, which as per linux-next may get to
v3.7-rc1, introduced adding a user namespace to a
struct seq_file. For older kernels with CONFIG_USER_NS
support just access the user_name space via the struct
file. For kernels without CONFIG_USER_NS pass the
init_user_ns. There is a special case to handle for
kernels with CONFIG_USER_NS prior to v2.6.38 --
see commit 47a150ed which added a struct user_namespace
to struct cred.
This backports:
commit adb37c4c67f807f16beb222028fb3ce9a354dc2b
Author: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Date: Wed May 23 18:01:20 2012 -0600
userns: Make seq_file's user namespace accessible
struct file already has a user namespace associated with it
in file->f_cred->user_ns, unfortunately because struct
seq_file has no struct file backpointer associated with
it, it is difficult to get at the user namespace in seq_file
context. Therefore add a helper function seq_user_ns to return
the associated user namespace and a user_ns field to struct
seq_file to be used in implementing seq_user_ns.
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
And for kernels older than v2.6.38 this is relevant to
review:
commit 47a150edc2ae734c0f4bf50aa19499e23b9a46f8
Author: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Date: Fri May 13 04:27:54 2011 +0100
Cache user_ns in struct cred
If !CONFIG_USERNS, have current_user_ns() defined to (&init_user_ns).
Get rid of _current_user_ns. This requires nsown_capable() to be
defined in capability.c rather than as static inline in capability.h,
so do that.
Request_key needs init_user_ns defined at current_user_ns if
!CONFIG_USERNS, so forward-declare that in cred.h if !CONFIG_USERNS
at current_user_ns() define.
Compile-tested with and without CONFIG_USERNS.
Signed-off-by: Serge E. Hallyn <serge.hallyn@xxxxxxxxxxxxx>
[ This makes a huge performance difference for acl_permission_check(),
up to 30%. And that is one of the hottest kernel functions for loads
that are pathname-lookup heavy. ]
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
mcgrof@garbanzo ~/compat (git::master)$ time ckmake
Trying kernel 3.5.0-030500-generic [OK]
Trying kernel 3.4.4-030404-generic [OK]
Trying kernel 3.3.7-030307-generic [OK]
Trying kernel 3.2.2-030202-generic [OK]
Trying kernel 3.1.10-030110-generic [OK]
Trying kernel 3.0.18-030018-generic [OK]
Trying kernel 2.6.39-02063904-generic [OK]
Trying kernel 2.6.38-02063808-generic [OK]
Trying kernel 2.6.37-02063706-generic [OK]
Trying kernel 2.6.36-02063604-generic [OK]
Trying kernel 2.6.35-02063512-generic [OK]
Trying kernel 2.6.34-02063410-generic [OK]
Trying kernel 2.6.33-02063305-generic [OK]
Trying kernel 2.6.32-02063255-generic [OK]
Trying kernel 2.6.31-02063113-generic [OK]
Trying kernel 2.6.30-02063010-generic [OK]
Trying kernel 2.6.29-02062906-generic [OK]
Trying kernel 2.6.28-02062810-generic [OK]
Trying kernel 2.6.27-020627-generic [OK]
Trying kernel 2.6.26-020626-generic [OK]
Trying kernel 2.6.25-020625-generic [OK]
Trying kernel 2.6.24-020624-generic [OK]
real 1m1.219s
user 3m19.912s
sys 0m31.102s
Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Luis R. Rodriguez <mcgrof@xxxxxxxxxxxxxxxx>
---
include/linux/compat-3.7.h | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/include/linux/compat-3.7.h b/include/linux/compat-3.7.h
index 80c2aad..2d7b6dd 100644
--- a/include/linux/compat-3.7.h
+++ b/include/linux/compat-3.7.h
@@ -10,9 +10,36 @@
#include <linux/pci.h>
#include <linux/pci_regs.h>
#include <linux/mm.h>
+#include <linux/user_namespace.h>
+#include <linux/file.h>
+#include <linux/seq_file.h>
#define VM_DONTDUMP VM_NODUMP
+#ifdef CONFIG_USER_NS
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,38))
+static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
+{
+ struct file *f = container_of((void *) seq, struct file, private_data);
+
+ return f->f_cred->user_ns;
+}
+#else
+static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
+{
+ return current_user_ns();
+}
+#endif /* (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,38)) */
+
+#else
+static inline struct user_namespace *seq_user_ns(struct seq_file *seq)
+{
+ extern struct user_namespace init_user_ns;
+ return &init_user_ns;
+}
+#endif /* CONFIG_USER_NS */
+
#define netlink_notify_portid(__notify) (__notify->pid)
#define genl_info_snd_portid(__genl_info) (__genl_info->snd_pid)
#define NETLINK_CB_PORTID(__skb) NETLINK_CB(cb->skb).pid
--
1.7.10.4
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