PATCH: ptrace support for fork/vfork/clone events [2/3]

From: Daniel Jacobowitz (dan@debian.org)
Date: Sun Oct 27 2002 - 13:52:13 EST


On Sun, Oct 27, 2002 at 01:50:38PM -0500, Daniel Jacobowitz wrote:
> 2. Add a new clone flag, CLONE_UNTRACED, and force it in all kernel_thread
> implementations. Needed by the next patch. This one touches every
> architecture and some of them in assembly; I've tried to get them all
> correct.

Here's the second one.

[Why is this needed? It's needed so that the debugger doesn't get
triggered on, say, a kernel-started modprobe process or some other
kernel thread. That'd confuse the debugger, beyond the other possible
security/stability problems.]

# This is a BitKeeper generated patch for the following project:
# Project Name: Linux kernel tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
# ChangeSet 1.809 -> 1.810
# arch/i386/kernel/process.c 1.32 -> 1.33
# arch/alpha/kernel/entry.S 1.15.1.2 -> 1.17
# arch/x86_64/kernel/process.c 1.7.1.3 -> 1.9
# include/linux/sched.h 1.94.1.14 -> 1.96
# arch/sparc/kernel/process.c 1.18 -> 1.19
# arch/s390x/kernel/process.c 1.10.1.4 -> 1.12
# arch/parisc/kernel/entry.S 1.3 -> 1.5
# arch/mips64/kernel/process.c 1.4 -> 1.5
# arch/ppc64/kernel/misc.S 1.28 -> 1.29
# arch/mips/kernel/process.c 1.7 -> 1.8
# arch/cris/kernel/entry.S 1.12 -> 1.13
# arch/sparc64/kernel/process.c 1.35 -> 1.36
# arch/ia64/kernel/process.c 1.15.1.1 -> 1.17
# arch/m68k/kernel/process.c 1.10 -> 1.11
# arch/cris/kernel/entryoffsets.c 1.3 -> 1.4
# arch/ppc64/kernel/asm-offsets.c 1.11 -> 1.12
# arch/sh/kernel/process.c 1.12 -> 1.13
# arch/s390/kernel/process.c 1.12.1.4 -> 1.14
# arch/arm/kernel/process.c 1.20 -> 1.21
# arch/ppc/kernel/misc.S 1.29 -> 1.30
# arch/alpha/kernel/asm-offsets.c 1.6 -> 1.7
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/26 drow@nevyn.them.org 1.810
# Merge to kernel.org
# --------------------------------------------
#
diff -Nru a/arch/alpha/kernel/asm-offsets.c b/arch/alpha/kernel/asm-offsets.c
--- a/arch/alpha/kernel/asm-offsets.c Sat Oct 26 20:09:43 2002
+++ b/arch/alpha/kernel/asm-offsets.c Sat Oct 26 20:09:43 2002
@@ -22,6 +22,7 @@
         BLANK();
         DEFINE(PT_PTRACED, PT_PTRACED);
         DEFINE(CLONE_VM, CLONE_VM);
+ DEFINE(CLONE_UNTRACED, CLONE_UNTRACED);
         DEFINE(SIGCHLD, SIGCHLD);
         BLANK();
         DEFINE(HAE_CACHE, offsetof(struct alpha_machine_vector, hae_cache));
diff -Nru a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
--- a/arch/alpha/kernel/entry.S Sat Oct 26 20:09:43 2002
+++ b/arch/alpha/kernel/entry.S Sat Oct 26 20:09:43 2002
@@ -212,7 +212,7 @@
         stq $2, 152($30) /* HAE */
 
         /* Shuffle FLAGS to the front; add CLONE_VM. */
- ldi $1, CLONE_VM
+ ldi $1, CLONE_VM|CLONE_UNTRACED
         or $18, $1, $16
         bsr $26, sys_clone
 
diff -Nru a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
--- a/arch/arm/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/arm/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -403,7 +403,7 @@
         b sys_exit \n\
 1: "
         : "=r" (__ret)
- : "Ir" (flags), "I" (CLONE_VM), "r" (fn), "r" (arg)
+ : "Ir" (flags), "r" (CLONE_VM | CLONE_UNTRACED), "r" (fn), "r" (arg)
         : "r0", "r1", "lr");
         return __ret;
 }
diff -Nru a/arch/cris/kernel/entry.S b/arch/cris/kernel/entry.S
--- a/arch/cris/kernel/entry.S Sat Oct 26 20:09:43 2002
+++ b/arch/cris/kernel/entry.S Sat Oct 26 20:09:43 2002
@@ -748,6 +748,7 @@
         /* r11 is argument 2 to clone, the flags */
         move.d $r12, $r11
         or.w LCLONE_VM, $r11
+ or.w LCLONE_UNTRACED, $r11
 
         /* Save FN for later. */
         move.d $r10, $r12
diff -Nru a/arch/cris/kernel/entryoffsets.c b/arch/cris/kernel/entryoffsets.c
--- a/arch/cris/kernel/entryoffsets.c Sat Oct 26 20:09:43 2002
+++ b/arch/cris/kernel/entryoffsets.c Sat Oct 26 20:09:43 2002
@@ -57,5 +57,6 @@
 
 /* linux/sched.h values - doesn't have an #ifdef __ASSEMBLY__ for these. */
 VAL (LCLONE_VM, CLONE_VM)
+VAL (LCLONE_UNTRACED, CLONE_UNTRACED)
 
 __asm__ (".endif");
diff -Nru a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
--- a/arch/i386/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/i386/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -224,7 +224,7 @@
         regs.eflags = 0x286;
 
         /* Ok, create the new process.. */
- p = do_fork(flags | CLONE_VM, 0, &regs, 0, NULL);
+ p = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL);
         return IS_ERR(p) ? PTR_ERR(p) : p->pid;
 }
 
diff -Nru a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
--- a/arch/ia64/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/ia64/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -514,7 +514,7 @@
         struct task_struct *parent = current;
         int result, tid;
 
- tid = clone(flags | CLONE_VM, 0);
+ tid = clone(flags | CLONE_VM | CLONE_UNTRACED, 0);
         if (parent != current) {
                 result = (*fn)(arg);
                 _exit(result);
diff -Nru a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
--- a/arch/m68k/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/m68k/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -152,7 +152,7 @@
 
         {
         register long retval __asm__ ("d0");
- register long clone_arg __asm__ ("d1") = flags | CLONE_VM;
+ register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 
         retval = __NR_clone;
         __asm__ __volatile__
diff -Nru a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c
--- a/arch/mips/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/mips/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -176,7 +176,7 @@
                 :"=r" (retval)
                 :"i" (__NR_clone), "i" (__NR_exit),
                  "r" (arg), "r" (fn),
- "r" (flags | CLONE_VM)
+ "r" (flags | CLONE_VM | CLONE_UNTRACED)
                  /*
                   * The called subroutine might have destroyed any of the
                   * at, result, argument or temporary registers ...
diff -Nru a/arch/mips64/kernel/process.c b/arch/mips64/kernel/process.c
--- a/arch/mips64/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/mips64/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -167,7 +167,7 @@
                 "1:\tmove\t%0, $2"
                 :"=r" (retval)
                 :"i" (__NR_clone), "i" (__NR_exit), "r" (arg), "r" (fn),
- "r" (flags | CLONE_VM)
+ "r" (flags | CLONE_VM | CLONE_UNTRACED)
 
                  /* The called subroutine might have destroyed any of the
                   * at, result, argument or temporary registers ... */
diff -Nru a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
--- a/arch/parisc/kernel/entry.S Sat Oct 26 20:09:43 2002
+++ b/arch/parisc/kernel/entry.S Sat Oct 26 20:09:43 2002
@@ -482,6 +482,7 @@
          */
 
 #define CLONE_VM 0x100 /* Must agree with <linux/sched.h> */
+#define CLONE_UNTRACED 0x00800000
 
         .export __kernel_thread, code
         .import do_fork
@@ -497,7 +498,8 @@
 #endif
         STREG %r26, PT_GR26(%r1) /* Store function & argument for child */
         STREG %r25, PT_GR25(%r1)
- ldo CLONE_VM(%r0), %r26 /* Force CLONE_VM since only init_mm */
+ ldil L%CLONE_UNTRACED, %r26
+ ldo CLONE_VM(%r26), %r26 /* Force CLONE_VM since only init_mm */
         or %r26, %r24, %r26 /* will have kernel mappings. */
         copy %r0, %r25
         bl do_fork_FIXME_NOW_RETURNS_TASK_STRUCT, %r2
diff -Nru a/arch/ppc/kernel/misc.S b/arch/ppc/kernel/misc.S
--- a/arch/ppc/kernel/misc.S Sat Oct 26 20:09:43 2002
+++ b/arch/ppc/kernel/misc.S Sat Oct 26 20:09:43 2002
@@ -1005,6 +1005,7 @@
         mr r30,r3 /* function */
         mr r31,r4 /* argument */
         ori r3,r5,CLONE_VM /* flags */
+ oris r3,r3,CLONE_UNTRACED>>16
         li r0,__NR_clone
         sc
         cmpi 0,r3,0 /* parent or child? */
diff -Nru a/arch/ppc64/kernel/asm-offsets.c b/arch/ppc64/kernel/asm-offsets.c
--- a/arch/ppc64/kernel/asm-offsets.c Sat Oct 26 20:09:43 2002
+++ b/arch/ppc64/kernel/asm-offsets.c Sat Oct 26 20:09:43 2002
@@ -157,6 +157,7 @@
         DEFINE(_SRR1, STACK_FRAME_OVERHEAD+sizeof(struct pt_regs)+8);
 
         DEFINE(CLONE_VM, CLONE_VM);
+ DEFINE(CLONE_UNTRACED, CLONE_UNTRACED);
 
         return 0;
 }
diff -Nru a/arch/ppc64/kernel/misc.S b/arch/ppc64/kernel/misc.S
--- a/arch/ppc64/kernel/misc.S Sat Oct 26 20:09:43 2002
+++ b/arch/ppc64/kernel/misc.S Sat Oct 26 20:09:43 2002
@@ -486,6 +486,7 @@
         /* XXX fix this when we optimise syscall entry to not save volatiles */
         mr r6,r3 /* function */
         ori r3,r5,CLONE_VM /* flags */
+ oris r3,r3,(CLONE_UNTRACED>>16)
         li r0,__NR_clone
         sc
         cmpi 0,r3,0 /* parent or child? */
diff -Nru a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
--- a/arch/s390/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/s390/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -146,7 +146,7 @@
         regs.orig_gpr2 = -1;
 
         /* Ok, create the new process.. */
- p = do_fork(flags | CLONE_VM, 0, &regs, 0, NULL);
+ p = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL);
         return IS_ERR(p) ? PTR_ERR(p) : p->pid;
 }
 
diff -Nru a/arch/s390x/kernel/process.c b/arch/s390x/kernel/process.c
--- a/arch/s390x/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/s390x/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -143,7 +143,7 @@
         regs.orig_gpr2 = -1;
 
         /* Ok, create the new process.. */
- p = do_fork(flags | CLONE_VM, 0, &regs, 0, NULL);
+ p = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL);
         return IS_ERR(p) ? PTR_ERR(p) : p->pid;
 }
 
diff -Nru a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
--- a/arch/sh/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/sh/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -120,7 +120,7 @@
 { /* Don't use this in BL=1(cli). Or else, CPU resets! */
         register unsigned long __sc0 __asm__ ("r0");
         register unsigned long __sc3 __asm__ ("r3") = __NR_clone;
- register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM;
+ register unsigned long __sc4 __asm__ ("r4") = (long) flags | CLONE_VM | CLONE_UNTRACED;
         register unsigned long __sc5 __asm__ ("r5") = 0;
         register unsigned long __sc8 __asm__ ("r8") = (long) arg;
         register unsigned long __sc9 __asm__ ("r9") = (long) fn;
diff -Nru a/arch/sparc/kernel/process.c b/arch/sparc/kernel/process.c
--- a/arch/sparc/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/sparc/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -726,7 +726,7 @@
                            /* Notreached by child. */
                            "1: mov %%o0, %0\n\t" :
                            "=r" (retval) :
- "i" (__NR_clone), "r" (flags | CLONE_VM),
+ "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
                            "i" (__NR_exit), "r" (fn), "r" (arg) :
                            "g1", "g2", "g3", "o0", "o1", "memory", "cc");
         return retval;
diff -Nru a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
--- a/arch/sparc64/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/sparc64/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -694,7 +694,7 @@
                            /* Notreached by child. */
                            "1:" :
                            "=r" (retval) :
- "i" (__NR_clone), "r" (flags | CLONE_VM),
+ "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
                            "i" (__NR_exit), "r" (fn), "r" (arg) :
                            "g1", "g2", "g3", "o0", "o1", "memory", "cc");
         return retval;
diff -Nru a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
--- a/arch/x86_64/kernel/process.c Sat Oct 26 20:09:43 2002
+++ b/arch/x86_64/kernel/process.c Sat Oct 26 20:09:43 2002
@@ -59,7 +59,7 @@
 asmlinkage extern void ret_from_fork(void);
 int sys_arch_prctl(int code, unsigned long addr);
 
-unsigned long kernel_thread_flags = CLONE_VM;
+unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
 int hlt_counter;
 
diff -Nru a/include/linux/sched.h b/include/linux/sched.h
--- a/include/linux/sched.h Sat Oct 26 20:09:43 2002
+++ b/include/linux/sched.h Sat Oct 26 20:09:43 2002
@@ -51,6 +51,7 @@
 #define CLONE_SETTID 0x00100000 /* write the TID back to userspace */
 #define CLONE_CLEARTID 0x00200000 /* clear the userspace TID */
 #define CLONE_DETACHED 0x00400000 /* parent wants no child-exit signal */
+#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
 
 /*
  * List of flags we want to share for kernel threads,

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer
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This archive was generated by hypermail 2b29 : Thu Oct 31 2002 - 22:00:33 EST