Date: Sun, 13 Oct 2019 16:21:48 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r353478 - stable/12/sys/kern Message-ID: <201910131621.x9DGLm9X081989@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: markj Date: Sun Oct 13 16:21:48 2019 New Revision: 353478 URL: https://svnweb.freebsd.org/changeset/base/353478 Log: MFC r352829: Fix some problems with the SPARSE_MAPPING option in the kernel linker. Modified: stable/12/sys/kern/link_elf.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/kern/link_elf.c ============================================================================== --- stable/12/sys/kern/link_elf.c Sun Oct 13 16:14:04 2019 (r353477) +++ stable/12/sys/kern/link_elf.c Sun Oct 13 16:21:48 2019 (r353478) @@ -40,6 +40,9 @@ __FBSDID("$FreeBSD$"); #include <sys/kernel.h> #include <sys/lock.h> #include <sys/malloc.h> +#ifdef SPARSE_MAPPING +#include <sys/mman.h> +#endif #include <sys/mutex.h> #include <sys/mount.h> #include <sys/pcpu.h> @@ -423,7 +426,7 @@ link_elf_init(void* arg) ef->address = 0; #endif #ifdef SPARSE_MAPPING - ef->object = 0; + ef->object = NULL; #endif ef->dynamic = dp; @@ -728,7 +731,7 @@ link_elf_link_preload(linker_class_t cls, ef->modptr = modptr; ef->address = *(caddr_t *)baseptr; #ifdef SPARSE_MAPPING - ef->object = 0; + ef->object = NULL; #endif dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; ef->dynamic = (Elf_Dyn *)dp; @@ -782,7 +785,7 @@ link_elf_load_file(linker_class_t cls, const char* fil struct nameidata nd; struct thread* td = curthread; /* XXX */ Elf_Ehdr *hdr; - caddr_t firstpage; + caddr_t firstpage, segbase; int nbytes, i; Elf_Phdr *phdr; Elf_Phdr *phlimit; @@ -949,47 +952,61 @@ link_elf_load_file(linker_class_t cls, const char* fil error = ENOMEM; goto out; } - ef->address = (caddr_t) vm_map_min(kernel_map); +#ifdef __amd64__ + mapbase = (caddr_t)KERNBASE; +#else + mapbase = (caddr_t)vm_map_min(kernel_map); +#endif + /* + * Mapping protections are downgraded after relocation processing. + */ error = vm_map_find(kernel_map, ef->object, 0, - (vm_offset_t *) &ef->address, mapsize, 0, VMFS_OPTIMAL_SPACE, + (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, VM_PROT_ALL, 0); if (error != 0) { vm_object_deallocate(ef->object); - ef->object = 0; + ef->object = NULL; goto out; } #else - ef->address = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); + mapbase = malloc(mapsize, M_LINKER, M_EXEC | M_WAITOK); #endif - mapbase = ef->address; + ef->address = mapbase; /* * Read the text and data sections and zero the bss. */ for (i = 0; i < nsegs; i++) { - caddr_t segbase = mapbase + segs[i]->p_vaddr - base_vaddr; - error = vn_rdwr(UIO_READ, nd.ni_vp, - segbase, segs[i]->p_filesz, segs[i]->p_offset, - UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, - &resid, td); - if (error != 0) - goto out; - bzero(segbase + segs[i]->p_filesz, - segs[i]->p_memsz - segs[i]->p_filesz); + segbase = mapbase + segs[i]->p_vaddr - base_vaddr; #ifdef SPARSE_MAPPING /* - * Wire down the pages + * Consecutive segments may have different mapping permissions, + * so be strict and verify that their mappings do not overlap. */ + if (((vm_offset_t)segbase & PAGE_MASK) != 0) { + error = EINVAL; + goto out; + } + error = vm_map_wire(kernel_map, - (vm_offset_t) segbase, - (vm_offset_t) segbase + segs[i]->p_memsz, - VM_MAP_WIRE_SYSTEM|VM_MAP_WIRE_NOHOLES); + (vm_offset_t)segbase, + (vm_offset_t)segbase + round_page(segs[i]->p_memsz), + VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); if (error != KERN_SUCCESS) { error = ENOMEM; goto out; } #endif + + error = vn_rdwr(UIO_READ, nd.ni_vp, + segbase, segs[i]->p_filesz, segs[i]->p_offset, + UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, + &resid, td); + if (error != 0) + goto out; + bzero(segbase + segs[i]->p_filesz, + segs[i]->p_memsz - segs[i]->p_filesz); } #ifdef GPROF @@ -1026,6 +1043,34 @@ link_elf_load_file(linker_class_t cls, const char* fil error = relocate_file(ef); if (error != 0) goto out; + +#ifdef SPARSE_MAPPING + /* + * Downgrade permissions on text segment mappings now that relocation + * processing is complete. Restrict permissions on read-only segments. + */ + for (i = 0; i < nsegs; i++) { + vm_prot_t prot; + + if (segs[i]->p_type != PT_LOAD) + continue; + + prot = VM_PROT_READ; + if ((segs[i]->p_flags & PF_W) != 0) + prot |= VM_PROT_WRITE; + if ((segs[i]->p_flags & PF_X) != 0) + prot |= VM_PROT_EXECUTE; + segbase = mapbase + segs[i]->p_vaddr - base_vaddr; + error = vm_map_protect(kernel_map, + (vm_offset_t)segbase, + (vm_offset_t)segbase + round_page(segs[i]->p_memsz), + prot, FALSE); + if (error != KERN_SUCCESS) { + error = ENOMEM; + goto out; + } + } +#endif /* * Try and load the symbol table if it's present. (you can
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201910131621.x9DGLm9X081989>