[PATCH] use ptrace_get_task_struct in various places
The ptrace_get_task_struct() helper that I added as part of the ptrace
consolidation is useful in variety of places that currently opencode it.
Switch them to the common helpers.
Add a ptrace_traceme() helper that needs to be explicitly called, and simplify
the ptrace_get_task_struct() interface. We don't need the request argument
now, and we return the task_struct directly, using ERR_PTR() for error
returns. It's a bit more code in the callers, but we have two sane routines
that do one thing well now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/alpha/kernel/ptrace.c b/arch/alpha/kernel/ptrace.c
index bbd3753..9969d21 100644
--- a/arch/alpha/kernel/ptrace.c
+++ b/arch/alpha/kernel/ptrace.c
@@ -265,30 +265,16 @@
lock_kernel();
DBG(DBG_MEM, ("request=%ld pid=%ld addr=0x%lx data=0x%lx\n",
request, pid, addr, data));
- ret = -EPERM;
if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED)
- goto out_notsk;
- ret = security_ptrace(current->parent, current);
- if (ret)
- goto out_notsk;
- /* set the ptrace bit in the process ptrace flags. */
- current->ptrace |= PT_PTRACED;
- ret = 0;
+ ret = ptrace_traceme();
goto out_notsk;
}
- if (pid == 1) /* you may not mess with init */
- goto out_notsk;
- ret = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
goto out_notsk;
+ }
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
diff --git a/arch/ia64/ia32/sys_ia32.c b/arch/ia64/ia32/sys_ia32.c
index dc28271..9f8e8d5 100644
--- a/arch/ia64/ia32/sys_ia32.c
+++ b/arch/ia64/ia32/sys_ia32.c
@@ -1761,21 +1761,15 @@
lock_kernel();
if (request == PTRACE_TRACEME) {
- ret = sys_ptrace(request, pid, addr, data);
+ ret = ptrace_traceme();
goto out;
}
- ret = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
goto out;
- ret = -EPERM;
- if (pid == 1) /* no messing around with init! */
- goto out_tsk;
+ }
if (request == PTRACE_ATTACH) {
ret = sys_ptrace(request, pid, addr, data);
diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index 4b19d04..8d88eee 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -1422,14 +1422,7 @@
lock_kernel();
ret = -EPERM;
if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED)
- goto out;
- ret = security_ptrace(current->parent, current);
- if (ret)
- goto out;
- current->ptrace |= PT_PTRACED;
- ret = 0;
+ ret = ptrace_traceme();
goto out;
}
diff --git a/arch/m32r/kernel/ptrace.c b/arch/m32r/kernel/ptrace.c
index 078d2a0..9b75caa 100644
--- a/arch/m32r/kernel/ptrace.c
+++ b/arch/m32r/kernel/ptrace.c
@@ -762,28 +762,16 @@
int ret;
lock_kernel();
- ret = -EPERM;
if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED)
- goto out;
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
- ret = 0;
+ ret = ptrace_traceme();
goto out;
}
- ret = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
- goto out;
- ret = -EPERM;
- if (pid == 1) /* you may not mess with init */
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
goto out;
+ }
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
diff --git a/arch/mips/kernel/ptrace32.c b/arch/mips/kernel/ptrace32.c
index 9a9b049..7e55457 100644
--- a/arch/mips/kernel/ptrace32.c
+++ b/arch/mips/kernel/ptrace32.c
@@ -57,30 +57,16 @@
(unsigned long) data);
#endif
lock_kernel();
- ret = -EPERM;
if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED)
- goto out;
- if ((ret = security_ptrace(current->parent, current)))
- goto out;
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
- ret = 0;
+ ret = ptrace_traceme();
goto out;
}
- ret = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
- goto out;
- ret = -EPERM;
- if (pid == 1) /* you may not mess with init */
- goto out_tsk;
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
diff --git a/arch/powerpc/kernel/ptrace32.c b/arch/powerpc/kernel/ptrace32.c
index 6176264..826ee3d 100644
--- a/arch/powerpc/kernel/ptrace32.c
+++ b/arch/powerpc/kernel/ptrace32.c
@@ -45,33 +45,19 @@
unsigned long data)
{
struct task_struct *child;
- int ret = -EPERM;
+ int ret;
lock_kernel();
if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED)
- goto out;
- ret = security_ptrace(current->parent, current);
- if (ret)
- goto out;
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
- ret = 0;
+ ret = ptrace_traceme();
goto out;
}
- ret = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
- goto out;
- ret = -EPERM;
- if (pid == 1) /* you may not mess with init */
- goto out_tsk;
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 8ecda6d..cc02232 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -712,35 +712,18 @@
int ret;
lock_kernel();
-
if (request == PTRACE_TRACEME) {
- /* are we already being traced? */
- ret = -EPERM;
- if (current->ptrace & PT_PTRACED)
- goto out;
- ret = security_ptrace(current->parent, current);
- if (ret)
- goto out;
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
+ ret = ptrace_traceme();
+ goto out;
+ }
+
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
goto out;
}
- ret = -EPERM;
- if (pid == 1) /* you may not mess with init */
- goto out;
-
- ret = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child)
- goto out;
-
ret = do_ptrace(child, request, addr, data);
-
put_task_struct(child);
out:
unlock_kernel();
diff --git a/arch/sparc/kernel/ptrace.c b/arch/sparc/kernel/ptrace.c
index 475c4c1..fc470c0 100644
--- a/arch/sparc/kernel/ptrace.c
+++ b/arch/sparc/kernel/ptrace.c
@@ -286,40 +286,17 @@
s, (int) request, (int) pid, addr, data, addr2);
}
#endif
+
if (request == PTRACE_TRACEME) {
- int my_ret;
-
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED) {
- pt_error_return(regs, EPERM);
- goto out;
- }
- my_ret = security_ptrace(current->parent, current);
- if (my_ret) {
- pt_error_return(regs, -my_ret);
- goto out;
- }
-
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
+ ret = ptrace_traceme();
pt_succ_return(regs, 0);
goto out;
}
-#ifndef ALLOW_INIT_TRACING
- if (pid == 1) {
- /* Can't dork with init. */
- pt_error_return(regs, EPERM);
- goto out;
- }
-#endif
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child) {
- pt_error_return(regs, ESRCH);
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ pt_error_return(regs, -ret);
goto out;
}
diff --git a/arch/sparc64/kernel/ptrace.c b/arch/sparc64/kernel/ptrace.c
index 774ecbb..84d3df2 100644
--- a/arch/sparc64/kernel/ptrace.c
+++ b/arch/sparc64/kernel/ptrace.c
@@ -198,39 +198,15 @@
}
#endif
if (request == PTRACE_TRACEME) {
- int ret;
-
- /* are we already being traced? */
- if (current->ptrace & PT_PTRACED) {
- pt_error_return(regs, EPERM);
- goto out;
- }
- ret = security_ptrace(current->parent, current);
- if (ret) {
- pt_error_return(regs, -ret);
- goto out;
- }
-
- /* set the ptrace bit in the process flags. */
- current->ptrace |= PT_PTRACED;
+ ret = ptrace_traceme();
pt_succ_return(regs, 0);
goto out;
}
-#ifndef ALLOW_INIT_TRACING
- if (pid == 1) {
- /* Can't dork with init. */
- pt_error_return(regs, EPERM);
- goto out;
- }
-#endif
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (!child) {
- pt_error_return(regs, ESRCH);
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ pt_error_return(regs, -ret);
goto out;
}
diff --git a/arch/x86_64/ia32/ptrace32.c b/arch/x86_64/ia32/ptrace32.c
index 2a925e2..5f4cdfa 100644
--- a/arch/x86_64/ia32/ptrace32.c
+++ b/arch/x86_64/ia32/ptrace32.c
@@ -196,36 +196,6 @@
#undef R32
-static struct task_struct *find_target(int request, int pid, int *err)
-{
- struct task_struct *child;
-
- *err = -EPERM;
- if (pid == 1)
- return NULL;
-
- *err = -ESRCH;
- read_lock(&tasklist_lock);
- child = find_task_by_pid(pid);
- if (child)
- get_task_struct(child);
- read_unlock(&tasklist_lock);
- if (child) {
- *err = -EPERM;
- if (child->pid == 1)
- goto out;
- *err = ptrace_check_attach(child, request == PTRACE_KILL);
- if (*err < 0)
- goto out;
- return child;
- }
- out:
- if (child)
- put_task_struct(child);
- return NULL;
-
-}
-
asmlinkage long sys32_ptrace(long request, u32 pid, u32 addr, u32 data)
{
struct task_struct *child;
@@ -254,9 +224,16 @@
break;
}
- child = find_target(request, pid, &ret);
- if (!child)
- return ret;
+ if (request == PTRACE_TRACEME)
+ return ptrace_traceme();
+
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child))
+ return PTR_ERR(child);
+
+ ret = ptrace_check_attach(child, request == PTRACE_KILL);
+ if (ret < 0)
+ goto out;
childregs = (struct pt_regs *)(child->thread.rsp0 - sizeof(struct pt_regs));
@@ -373,6 +350,7 @@
break;
}
+ out:
put_task_struct(child);
return ret;
}
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index b2b3dba..8647919 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -80,6 +80,8 @@
extern long arch_ptrace(struct task_struct *child, long request, long addr, long data);
+extern struct task_struct *ptrace_get_task_struct(pid_t pid);
+extern int ptrace_traceme(void);
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
extern int ptrace_attach(struct task_struct *tsk);
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 656476e..cceaf09 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -408,54 +408,62 @@
return ret;
}
-#ifndef __ARCH_SYS_PTRACE
-static int ptrace_get_task_struct(long request, long pid,
- struct task_struct **childp)
+/**
+ * ptrace_traceme -- helper for PTRACE_TRACEME
+ *
+ * Performs checks and sets PT_PTRACED.
+ * Should be used by all ptrace implementations for PTRACE_TRACEME.
+ */
+int ptrace_traceme(void)
{
- struct task_struct *child;
int ret;
/*
- * Callers use child == NULL as an indication to exit early even
- * when the return value is 0, so make sure it is non-NULL here.
+ * Are we already being traced?
*/
- *childp = NULL;
+ if (current->ptrace & PT_PTRACED)
+ return -EPERM;
+ ret = security_ptrace(current->parent, current);
+ if (ret)
+ return -EPERM;
+ /*
+ * Set the ptrace bit in the process ptrace flags.
+ */
+ current->ptrace |= PT_PTRACED;
+ return 0;
+}
- if (request == PTRACE_TRACEME) {
- /*
- * Are we already being traced?
- */
- if (current->ptrace & PT_PTRACED)
- return -EPERM;
- ret = security_ptrace(current->parent, current);
- if (ret)
- return -EPERM;
- /*
- * Set the ptrace bit in the process ptrace flags.
- */
- current->ptrace |= PT_PTRACED;
- return 0;
- }
+/**
+ * ptrace_get_task_struct -- grab a task struct reference for ptrace
+ * @pid: process id to grab a task_struct reference of
+ *
+ * This function is a helper for ptrace implementations. It checks
+ * permissions and then grabs a task struct for use of the actual
+ * ptrace implementation.
+ *
+ * Returns the task_struct for @pid or an ERR_PTR() on failure.
+ */
+struct task_struct *ptrace_get_task_struct(pid_t pid)
+{
+ struct task_struct *child;
/*
- * You may not mess with init
+ * Tracing init is not allowed.
*/
if (pid == 1)
- return -EPERM;
+ return ERR_PTR(-EPERM);
- ret = -ESRCH;
read_lock(&tasklist_lock);
child = find_task_by_pid(pid);
if (child)
get_task_struct(child);
read_unlock(&tasklist_lock);
if (!child)
- return -ESRCH;
-
- *childp = child;
- return 0;
+ return ERR_PTR(-ESRCH);
+ return child;
}
+#ifndef __ARCH_SYS_PTRACE
asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
{
struct task_struct *child;
@@ -465,9 +473,16 @@
* This lock_kernel fixes a subtle race with suid exec
*/
lock_kernel();
- ret = ptrace_get_task_struct(request, pid, &child);
- if (!child)
+ if (request == PTRACE_TRACEME) {
+ ret = ptrace_traceme();
goto out;
+ }
+
+ child = ptrace_get_task_struct(pid);
+ if (IS_ERR(child)) {
+ ret = PTR_ERR(child);
+ goto out;
+ }
if (request == PTRACE_ATTACH) {
ret = ptrace_attach(child);