The branch main has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=3a56cfedbc701f8026d38c0d808c614c9f0572ae
commit 3a56cfedbc701f8026d38c0d808c614c9f0572ae Author: Mark Johnston <[email protected]> AuthorDate: 2022-03-01 16:53:42 +0000 Commit: Mark Johnston <[email protected]> CommitDate: 2022-03-01 17:40:35 +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 <[email protected]> MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D34304 --- 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 f92070d8088d..c40b4b94e38d 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;
