X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fptrace.c;h=c9cf48b21f052a620b34151cc9de6c4b48f4ad66;hb=e478075c6f07a383c378fb400edc1a7407a941b0;hp=49849d12dd123aa2971c933c81936c59199fce78;hpb=b6dff3ec5e116e3af6f537d4caedcad6b9e5082a;p=safe%2Fjmp%2Flinux-2.6

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 49849d1..c9cf48b 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);
 }
@@ -115,7 +127,7 @@ int ptrace_check_attach(struct task_struct *child, int kill)
 
 int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 {
-	struct cred *cred = current->cred, *tcred = task->cred;
+	const struct cred *cred = current_cred(), *tcred;
 
 	/* May we inspect the given task?
 	 * This check is used both for attaching with ptrace
@@ -125,19 +137,23 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
 	 * because setting up the necessary parent/child relationship
 	 * or halting the specified task is impossible.
 	 */
-	uid_t uid = cred->uid;
-	gid_t gid = cred->gid;
 	int dumpable = 0;
 	/* Don't let security modules deny introspection */
 	if (task == current)
 		return 0;
-	if ((uid != tcred->euid ||
-	     uid != tcred->suid ||
-	     uid != tcred->uid  ||
-	     gid != tcred->egid ||
-	     gid != tcred->sgid ||
-	     gid != tcred->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);
@@ -167,6 +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.
@@ -206,6 +230,7 @@ repeat:
 bad:
 	write_unlock_irqrestore(&tasklist_lock, flags);
 	task_unlock(task);
+	mutex_unlock(&current->cred_exec_mutex);
 out:
 	return retval;
 }
@@ -549,7 +574,7 @@ struct task_struct *ptrace_get_task_struct(pid_t pid)
 #define arch_ptrace_attach(child)	do { } while (0)
 #endif
 
-asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
+SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data)
 {
 	struct task_struct *child;
 	long ret;
@@ -616,7 +641,7 @@ int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
 	return (copied == sizeof(data)) ? 0 : -EIO;
 }
 
-#if defined CONFIG_COMPAT && defined __ARCH_WANT_COMPAT_SYS_PTRACE
+#if defined CONFIG_COMPAT
 #include <linux/compat.h>
 
 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
@@ -713,4 +738,4 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
 	unlock_kernel();
 	return ret;
 }
-#endif	/* CONFIG_COMPAT && __ARCH_WANT_COMPAT_SYS_PTRACE */
+#endif	/* CONFIG_COMPAT */