git: c04e4ff6168a - stable/13 - fasttrap: Avoid creating WX mappings

The branch stable/13 has been updated by markj:

URL: https://cgit.FreeBSD.org/src/commit/?id=c04e4ff6168a419de1d11a7b4335d9874370b60c

commit c04e4ff6168a419de1d11a7b4335d9874370b60c
Author:     Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2022-03-01 16:53:42 +0000
Commit:     Mark Johnston <markj@FreeBSD.org>
CommitDate: 2022-03-15 15:40:47 +0000

    fasttrap: Avoid creating WX mappings
    
    fasttrap instruments certain instructions by overwriting them and
    copying the original instruction to some per-thread scratch space which
    is executed after the probe fires.  This trampoline jumps back to the
    tracepoint after executing the original instruction.
    
    The created mapping has both write and execute permissions, and so this
    mechanism doesn't work when allow_wx is disabled.  Work around the
    restriction by using proc_rwmem() to write to the trampoline.
    
    Reviewed by:    vangyzen
    Tested by:      Amit <akamit91@hotmail.com>
    Sponsored by:   The FreeBSD Foundation
    
    (cherry picked from commit 3a56cfedbc701f8026d38c0d808c614c9f0572ae)
---
 sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c    | 5 +++--
 sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c b/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
index d96d3f44182e..04ef3ecc3e8d 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
@@ -336,8 +336,9 @@ fasttrap_scraddr(struct thread *td, fasttrap_proc_t *fprc)
 		 */
 		addr = 0;
 		error = vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr,
-		    FASTTRAP_SCRBLOCK_SIZE, 0, VMFS_ANY_SPACE, VM_PROT_ALL,
-		    VM_PROT_ALL, 0);
+		    FASTTRAP_SCRBLOCK_SIZE, 0, VMFS_ANY_SPACE,
+		    VM_PROT_READ | VM_PROT_EXECUTE,
+		    VM_PROT_READ | VM_PROT_EXECUTE, MAP_COPY_ON_WRITE);
 		if (error != KERN_SUCCESS)
 			goto done;
 
diff --git a/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c b/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c
index 502273b73157..163a8fdd13fa 100644
--- a/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c
+++ b/sys/cddl/contrib/opensolaris/uts/intel/dtrace/fasttrap_isa.c
@@ -1666,7 +1666,7 @@ fasttrap_pid_probe(struct trapframe *tf)
 
 		ASSERT(i <= sizeof (scratch));
 
-		if (fasttrap_copyout(scratch, (char *)addr, i)) {
+		if (uwrite(curproc, scratch, i, addr) != 0) {
 			fasttrap_sigtrap(p, curthread, pc);
 			new_pc = pc;
 			break;