[PATCH 05/21] userns: Make seq_file's user namespace accessible
From: Eric W. Biederman <hidden>
Date: 2012-08-13 20:20:19
Also in:
lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> 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 <redacted> Cc: Eric Dumazet <redacted> Cc: KAMEZAWA Hiroyuki <redacted> Cc: Alexey Dobriyan <redacted> Acked-by: Serge Hallyn <redacted> Signed-off-by: Eric W. Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> --- fs/seq_file.c | 4 ++++ include/linux/seq_file.h | 14 ++++++++++++++ 2 files changed, 18 insertions(+), 0 deletions(-)
diff --git a/fs/seq_file.c b/fs/seq_file.c
index 14cf9de..99dffab 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c@@ -9,6 +9,7 @@ #include <linux/export.h> #include <linux/seq_file.h> #include <linux/slab.h> +#include <linux/cred.h> #include <asm/uaccess.h> #include <asm/page.h>
@@ -56,6 +57,9 @@ int seq_open(struct file *file, const struct seq_operations *op) memset(p, 0, sizeof(*p)); mutex_init(&p->lock); p->op = op; +#ifdef CONFIG_USER_NS + p->user_ns = file->f_cred->user_ns; +#endif /* * Wrappers around seq_open(e.g. swaps_open) need to be
diff --git a/include/linux/seq_file.h b/include/linux/seq_file.h
index 83c44ee..68a04a3 100644
--- a/include/linux/seq_file.h
+++ b/include/linux/seq_file.h@@ -13,6 +13,7 @@ struct file; struct path; struct inode; struct dentry; +struct user_namespace; struct seq_file { char *buf;
@@ -25,6 +26,9 @@ struct seq_file { struct mutex lock; const struct seq_operations *op; int poll_event; +#ifdef CONFIG_USER_NS + struct user_namespace *user_ns; +#endif void *private; };
@@ -128,6 +132,16 @@ int seq_put_decimal_ull(struct seq_file *m, char delimiter, int seq_put_decimal_ll(struct seq_file *m, char delimiter, long long num); +static inline struct user_namespace *seq_user_ns(struct seq_file *seq) +{ +#ifdef CONFIG_USER_NS + return seq->user_ns; +#else + extern struct user_namespace init_user_ns; + return &init_user_ns; +#endif +} + #define SEQ_START_TOKEN ((void *)1) /* * Helpers for iteration over list_head-s in seq_files
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1.7.5.4