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-rw-r--r--fs/proc/base.c35
-rw-r--r--include/linux/ptrace.h1
-rw-r--r--kernel/ptrace.c41
3 files changed, 33 insertions, 44 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 24eed13..84751f3 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -346,33 +346,6 @@ static int proc_root_link(struct inode *inode, struct dentry **dentry, struct vf
(task->state == TASK_STOPPED || task->state == TASK_TRACED) && \
security_ptrace(current,task) == 0))
-static int may_ptrace_attach(struct task_struct *task)
-{
- int retval = 0;
-
- task_lock(task);
-
- if (!task->mm)
- goto out;
- 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))
- goto out;
- rmb();
- if (task->mm->dumpable != 1 && !capable(CAP_SYS_PTRACE))
- goto out;
- if (security_ptrace(current, task))
- goto out;
-
- retval = 1;
-out:
- task_unlock(task);
- return retval;
-}
-
static int proc_pid_environ(struct task_struct *task, char * buffer)
{
int res = 0;
@@ -382,7 +355,7 @@ static int proc_pid_environ(struct task_struct *task, char * buffer)
if (len > PAGE_SIZE)
len = PAGE_SIZE;
res = access_process_vm(task, mm->env_start, buffer, len, 0);
- if (!may_ptrace_attach(task))
+ if (!ptrace_may_attach(task))
res = -ESRCH;
mmput(mm);
}
@@ -685,7 +658,7 @@ static ssize_t mem_read(struct file * file, char __user * buf,
int ret = -ESRCH;
struct mm_struct *mm;
- if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
+ if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
goto out;
ret = -ENOMEM;
@@ -711,7 +684,7 @@ static ssize_t mem_read(struct file * file, char __user * buf,
this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
retval = access_process_vm(task, src, page, this_len, 0);
- if (!retval || !MAY_PTRACE(task) || !may_ptrace_attach(task)) {
+ if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) {
if (!ret)
ret = -EIO;
break;
@@ -749,7 +722,7 @@ static ssize_t mem_write(struct file * file, const char * buf,
struct task_struct *task = proc_task(file->f_dentry->d_inode);
unsigned long dst = *ppos;
- if (!MAY_PTRACE(task) || !may_ptrace_attach(task))
+ if (!MAY_PTRACE(task) || !ptrace_may_attach(task))
return -ESRCH;
page = (char *)__get_free_page(GFP_USER);
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 2afdafb..dc6f364 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -90,6 +90,7 @@ extern void __ptrace_link(struct task_struct *child,
struct task_struct *new_parent);
extern void __ptrace_unlink(struct task_struct *child);
extern void ptrace_untrace(struct task_struct *child);
+extern int ptrace_may_attach(struct task_struct *task);
static inline void ptrace_link(struct task_struct *child,
struct task_struct *new_parent)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 8dcb8f6..019e04e 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -118,6 +118,33 @@ int ptrace_check_attach(struct task_struct *child, int kill)
return ret;
}
+static int may_attach(struct task_struct *task)
+{
+ if (!task->mm)
+ return -EPERM;
+ 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))
+ return -EPERM;
+ smp_rmb();
+ if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
+ return -EPERM;
+
+ return security_ptrace(current, task);
+}
+
+int ptrace_may_attach(struct task_struct *task)
+{
+ int err;
+ task_lock(task);
+ err = may_attach(task);
+ task_unlock(task);
+ return !err;
+}
+
int ptrace_attach(struct task_struct *task)
{
int retval;
@@ -127,22 +154,10 @@ int ptrace_attach(struct task_struct *task)
goto bad;
if (task == current)
goto bad;
- if (!task->mm)
- goto bad;
- 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))
- goto bad;
- smp_rmb();
- if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
- goto bad;
/* the same process cannot be attached many times */
if (task->ptrace & PT_PTRACED)
goto bad;
- retval = security_ptrace(current, task);
+ retval = may_attach(task);
if (retval)
goto bad;
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