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Diffstat (limited to 'kernel/ptrace.c')
-rw-r--r--kernel/ptrace.c42
1 files changed, 36 insertions, 6 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index e82c15cadd6d..49ba7c1ade9d 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -27,6 +27,35 @@
#include <linux/cn_proc.h>
#include <linux/compat.h>
+/*
+ * Access another process' address space via ptrace.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
+ void *buf, int len, unsigned int gup_flags)
+{
+ struct mm_struct *mm;
+ int ret;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ if (!tsk->ptrace ||
+ (current != tsk->parent) ||
+ ((get_dumpable(mm) != SUID_DUMP_USER) &&
+ !ptracer_capable(tsk, mm->user_ns))) {
+ mmput(mm);
+ return 0;
+ }
+
+ ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
+ mmput(mm);
+
+ return ret;
+}
+
/*
* ptrace a task: make the debugger its new parent and
@@ -535,7 +564,8 @@ int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst
int this_len, retval;
this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
- retval = access_process_vm(tsk, src, buf, this_len, FOLL_FORCE);
+ retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
+
if (!retval) {
if (copied)
break;
@@ -562,7 +592,7 @@ int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long ds
this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
if (copy_from_user(buf, src, this_len))
return -EFAULT;
- retval = access_process_vm(tsk, dst, buf, this_len,
+ retval = ptrace_access_vm(tsk, dst, buf, this_len,
FOLL_FORCE | FOLL_WRITE);
if (!retval) {
if (copied)
@@ -1126,7 +1156,7 @@ int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
unsigned long tmp;
int copied;
- copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
+ copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
if (copied != sizeof(tmp))
return -EIO;
return put_user(tmp, (unsigned long __user *)data);
@@ -1137,7 +1167,7 @@ int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
{
int copied;
- copied = access_process_vm(tsk, addr, &data, sizeof(data),
+ copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
FOLL_FORCE | FOLL_WRITE);
return (copied == sizeof(data)) ? 0 : -EIO;
}
@@ -1155,7 +1185,7 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
switch (request) {
case PTRACE_PEEKTEXT:
case PTRACE_PEEKDATA:
- ret = access_process_vm(child, addr, &word, sizeof(word),
+ ret = ptrace_access_vm(child, addr, &word, sizeof(word),
FOLL_FORCE);
if (ret != sizeof(word))
ret = -EIO;
@@ -1165,7 +1195,7 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
case PTRACE_POKETEXT:
case PTRACE_POKEDATA:
- ret = access_process_vm(child, addr, &data, sizeof(data),
+ ret = ptrace_access_vm(child, addr, &data, sizeof(data),
FOLL_FORCE | FOLL_WRITE);
ret = (ret != sizeof(data) ? -EIO : 0);
break;