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-rw-r--r--kernel/ptrace.c41
1 files changed, 35 insertions, 6 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 4c8bcd7dd8e..29dc700e198 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -25,6 +25,17 @@
#include <asm/pgtable.h>
#include <asm/uaccess.h>
+
+/*
+ * Initialize a new task whose father had been ptraced.
+ *
+ * Called from copy_process().
+ */
+void ptrace_fork(struct task_struct *child, unsigned long clone_flags)
+{
+ arch_ptrace_fork(child, clone_flags);
+}
+
/*
* ptrace a task: make the debugger its new parent and
* move it to the ptrace list.
@@ -72,6 +83,7 @@ void __ptrace_unlink(struct task_struct *child)
child->parent = child->real_parent;
list_del_init(&child->ptrace_entry);
+ arch_ptrace_untrace(child);
if (task_is_traced(child))
ptrace_untrace(child);
}
@@ -115,6 +127,8 @@ int ptrace_check_attach(struct task_struct *child, int kill)
int __ptrace_may_access(struct task_struct *task, unsigned int mode)
{
+ const struct cred *cred = current_cred(), *tcred;
+
/* May we inspect the given task?
* This check is used both for attaching with ptrace
* and for allowing access to sensitive information in /proc.
@@ -127,13 +141,19 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
/* Don't let security modules deny introspection */
if (task == current)
return 0;
- if (((current->uid != task->euid) ||
- (current->uid != task->suid) ||
- (current->uid != task->uid) ||
- (current->gid != task->egid) ||
- (current->gid != task->sgid) ||
- (current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if ((cred->uid != tcred->euid ||
+ cred->uid != tcred->suid ||
+ cred->uid != tcred->uid ||
+ cred->gid != tcred->egid ||
+ cred->gid != tcred->sgid ||
+ cred->gid != tcred->gid) &&
+ !capable(CAP_SYS_PTRACE)) {
+ rcu_read_unlock();
return -EPERM;
+ }
+ rcu_read_unlock();
smp_rmb();
if (task->mm)
dumpable = get_dumpable(task->mm);
@@ -163,6 +183,14 @@ int ptrace_attach(struct task_struct *task)
if (same_thread_group(task, current))
goto out;
+ /* Protect exec's credential calculations against our interference;
+ * SUID, SGID and LSM creds get determined differently under ptrace.
+ */
+ retval = mutex_lock_interruptible(&current->cred_exec_mutex);
+ if (retval < 0)
+ goto out;
+
+ retval = -EPERM;
repeat:
/*
* Nasty, nasty.
@@ -202,6 +230,7 @@ repeat:
bad:
write_unlock_irqrestore(&tasklist_lock, flags);
task_unlock(task);
+ mutex_unlock(&current->cred_exec_mutex);
out:
return retval;
}