Add the helper pid_entry_access() to unify the permission checks during
->open()
This is a preparation patch.
Signed-off-by: Djalal Harouni <tix...@opendz.org>
---
fs/proc/generic.c | 22 ++++++++++++++++++++++
fs/proc/internal.h | 2 ++
2 files changed, 24 insertions(+)
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index b7f268e..98ed927 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -23,6 +23,7 @@
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
+#include <linux/ptrace.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -596,3 +597,24 @@ void *PDE_DATA(const struct inode *inode)
return __PDE_DATA(inode);
}
EXPORT_SYMBOL(PDE_DATA);
+
+int pid_entry_access(struct file *filp, unsigned int mode)
+{
+ int err = -ESRCH;
+ struct task_struct *task = get_proc_task(file_inode(filp));
+
+ if (!task)
+ return err;
+
+ err = mutex_lock_killable(&task->signal->cred_guard_mutex);
+ if (err)
+ goto out;
+
+ if (!ptrace_may_access(task, mode))
+ err = -EACCES;
+
+ mutex_unlock(&task->signal->cred_guard_mutex);
+out:
+ put_task_struct(task);
+ return err;
+}
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index e696284..4f828fa 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -202,6 +202,8 @@ static inline struct proc_dir_entry *pde_get(struct
proc_dir_entry *pde)
}
extern void pde_put(struct proc_dir_entry *);
+extern int pid_entry_access(struct file *filp, unsigned int mode);
+
/*
* inode.c
*/
--
1.7.11.7
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