On Fri, 20 Jul 2001, Andrew Morton wrote:
>
> I tested various other possible problems, such as making
> /sbin/hotplug an elf executable and it looks OK, apart from
> the /proc problem.
Actually, there's a double stupidity in the dumpable testing: it should
really test that the process has a VM, but it should also make sure to
lock that access properly.
This ends up being even more of an issue for ptrace, I think. Sorry for
the screw-up. I think the real fix should be something along the lines of
this (actually, we should move the whole ptrace executable test into
ptrace_dumpable: right now x86 is the only one that gets the subtle and
unlikely race with a ptrace and a suid executable right with the memory
access ordering things).
Linus
----
diff -u --recursive --new-file pre9/linux/arch/alpha/kernel/ptrace.c
linux/arch/alpha/kernel/ptrace.c
--- pre9/linux/arch/alpha/kernel/ptrace.c Fri Jul 20 01:02:50 2001
+++ linux/arch/alpha/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -267,7 +267,7 @@
ret = -EPERM;
if (child == current)
goto out;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/arm/kernel/ptrace.c
linux/arch/arm/kernel/ptrace.c
--- pre9/linux/arch/arm/kernel/ptrace.c Fri Jul 20 01:02:50 2001
+++ linux/arch/arm/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -596,7 +596,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/cris/kernel/ptrace.c
linux/arch/cris/kernel/ptrace.c
--- pre9/linux/arch/cris/kernel/ptrace.c Fri Jul 20 01:02:51 2001
+++ linux/arch/cris/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -117,7 +117,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/i386/kernel/ptrace.c
linux/arch/i386/kernel/ptrace.c
--- pre9/linux/arch/i386/kernel/ptrace.c Fri Jul 20 01:02:52 2001
+++ linux/arch/i386/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -176,7 +176,7 @@
(current->gid != child->gid)) && !capable(CAP_SYS_PTRACE))
goto out_tsk;
rmb();
- if (!child->mm->dumpable && !capable(CAP_SYS_PTRACE))
+ if (!ptrace_dumpable(child) && !capable(CAP_SYS_PTRACE))
goto out_tsk;
/* the same process cannot be attached many times */
if (child->ptrace & PT_PTRACED)
diff -u --recursive --new-file pre9/linux/arch/ia64/kernel/ptrace.c
linux/arch/ia64/kernel/ptrace.c
--- pre9/linux/arch/ia64/kernel/ptrace.c Fri Jul 20 01:02:52 2001
+++ linux/arch/ia64/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -770,7 +770,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/m68k/kernel/ptrace.c
linux/arch/m68k/kernel/ptrace.c
--- pre9/linux/arch/m68k/kernel/ptrace.c Fri Jul 20 01:02:52 2001
+++ linux/arch/m68k/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -120,7 +120,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/mips/kernel/ptrace.c
linux/arch/mips/kernel/ptrace.c
--- pre9/linux/arch/mips/kernel/ptrace.c Fri Jul 20 01:02:52 2001
+++ linux/arch/mips/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -68,7 +68,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/mips64/kernel/ptrace.c
linux/arch/mips64/kernel/ptrace.c
--- pre9/linux/arch/mips64/kernel/ptrace.c Fri Jul 20 01:02:52 2001
+++ linux/arch/mips64/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -64,7 +64,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
@@ -338,7 +338,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/parisc/kernel/ptrace.c
linux/arch/parisc/kernel/ptrace.c
--- pre9/linux/arch/parisc/kernel/ptrace.c Fri Jul 20 01:02:52 2001
+++ linux/arch/parisc/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -63,7 +63,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/ppc/kernel/ptrace.c
linux/arch/ppc/kernel/ptrace.c
--- pre9/linux/arch/ppc/kernel/ptrace.c Fri Jul 20 01:02:53 2001
+++ linux/arch/ppc/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -120,7 +120,7 @@
if (request == PTRACE_ATTACH) {
if (child == current)
goto out_tsk;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/s390/kernel/ptrace.c
linux/arch/s390/kernel/ptrace.c
--- pre9/linux/arch/s390/kernel/ptrace.c Fri Jul 20 01:02:53 2001
+++ linux/arch/s390/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -235,7 +235,7 @@
{
if (child == current)
goto out;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/s390x/kernel/ptrace.c
linux/arch/s390x/kernel/ptrace.c
--- pre9/linux/arch/s390x/kernel/ptrace.c Fri Jul 20 01:02:53 2001
+++ linux/arch/s390x/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -249,7 +249,7 @@
{
if (child == current)
goto out;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
@@ -435,7 +435,7 @@
{
if (child == current)
goto out;
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->suid) ||
(current->uid != child->uid) ||
diff -u --recursive --new-file pre9/linux/arch/sh/kernel/ptrace.c
linux/arch/sh/kernel/ptrace.c
--- pre9/linux/arch/sh/kernel/ptrace.c Fri Jul 20 01:02:53 2001
+++ linux/arch/sh/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -184,7 +184,7 @@
(tsk->gid != child->gid)) && !capable(CAP_SYS_PTRACE))
goto out_tsk;
rmb();
- if (!child->mm->dumpable && !capable(CAP_SYS_PTRACE))
+ if (!ptrace_dumpable(child) && !capable(CAP_SYS_PTRACE))
goto out_tsk;
/* the same process cannot be attached many times */
if (child->ptrace & PT_PTRACED)
diff -u --recursive --new-file pre9/linux/arch/sparc/kernel/ptrace.c
linux/arch/sparc/kernel/ptrace.c
--- pre9/linux/arch/sparc/kernel/ptrace.c Fri Jul 20 01:02:53 2001
+++ linux/arch/sparc/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -327,7 +327,7 @@
pt_error_return(regs, EPERM);
goto out_tsk;
}
- if((!child->mm->dumpable ||
+ if((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->uid) ||
(current->uid != child->suid) ||
diff -u --recursive --new-file pre9/linux/arch/sparc64/kernel/ptrace.c
linux/arch/sparc64/kernel/ptrace.c
--- pre9/linux/arch/sparc64/kernel/ptrace.c Fri Jul 20 01:02:54 2001
+++ linux/arch/sparc64/kernel/ptrace.c Fri Jul 20 01:01:43 2001
@@ -177,7 +177,7 @@
pt_error_return(regs, EPERM);
goto out_tsk;
}
- if ((!child->mm->dumpable ||
+ if ((!ptrace_dumpable(child) ||
(current->uid != child->euid) ||
(current->uid != child->uid) ||
(current->uid != child->suid) ||
diff -u --recursive --new-file pre9/linux/fs/proc/base.c linux/fs/proc/base.c
--- pre9/linux/fs/proc/base.c Fri Jul 20 01:03:03 2001
+++ linux/fs/proc/base.c Fri Jul 20 00:59:38 2001
@@ -670,7 +670,7 @@
inode->u.proc_i.task = task;
inode->i_uid = 0;
inode->i_gid = 0;
- if (ino == PROC_PID_INO || task->mm->dumpable) {
+ if (ino == PROC_PID_INO || ptrace_dumpable(task)) {
inode->i_uid = task->euid;
inode->i_gid = task->egid;
}
diff -u --recursive --new-file pre9/linux/include/linux/mm.h linux/include/linux/mm.h
--- pre9/linux/include/linux/mm.h Tue Jul 3 15:42:55 2001
+++ linux/include/linux/mm.h Fri Jul 20 00:59:22 2001
@@ -442,6 +442,7 @@
extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf,
int len, int write);
extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char *dst, int
len);
extern int ptrace_writedata(struct task_struct *tsk, char * src, unsigned long dst,
int len);
+extern int ptrace_dumpable(struct task_struct *tsk);
/*
* On a two-level page table, this ends up being trivial. Thus the
diff -u --recursive --new-file pre9/linux/kernel/ptrace.c linux/kernel/ptrace.c
--- pre9/linux/kernel/ptrace.c Mon Mar 19 12:35:08 2001
+++ linux/kernel/ptrace.c Fri Jul 20 00:58:46 2001
@@ -16,6 +16,19 @@
#include <asm/pgtable.h>
#include <asm/uaccess.h>
+int ptrace_dumpable(struct task_struct *task)
+{
+ int dumpable = 0;
+ struct mm_struct *mm;
+
+ task_lock(task);
+ mm = task->mm;
+ if (mm)
+ dumpable = mm->dumpable;
+ task_unlock(task);
+ return dumpable;
+}
+
/*
* Access another process' address space, one page at a time.
*/
-
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