freebsd-dev/sys/i386/ibcs2/imgact_coff.c
Konstantin Belousov 140dedb81c The r241025 fixed the case when a binary, executed from nullfs mount,
was still possible to open for write from the lower filesystem.  There
is a symmetric situation where the binary could already has file
descriptors opened for write, but it can be executed from the nullfs
overlay.

Handle the issue by passing one v_writecount reference to the lower
vnode if nullfs vnode has non-zero v_writecount.  Note that only one
write reference can be donated, since nullfs only keeps one use
reference on the lower vnode.  Always use the lower vnode v_writecount
for the checks.

Introduce the VOP_GET_WRITECOUNT to read v_writecount, which is
currently always bypassed to the lower vnode, and VOP_ADD_WRITECOUNT
to manipulate the v_writecount value, which manages a single bypass
reference to the lower vnode.  Caling the VOPs instead of directly
accessing v_writecount provide the fix described in the previous
paragraph.

Tested by:	pho
MFC after:	3 weeks
2012-11-02 13:56:36 +00:00

494 lines
14 KiB
C

/*-
* Copyright (c) 1994 Sean Eric Fagan
* Copyright (c) 1994 Søren Schmidt
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/exec.h>
#include <sys/fcntl.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <i386/ibcs2/coff.h>
#include <i386/ibcs2/ibcs2_util.h>
MODULE_DEPEND(coff, ibcs2, 1, 1, 1);
extern struct sysentvec ibcs2_svr3_sysvec;
static int coff_load_file(struct thread *td, char *name);
static int exec_coff_imgact(struct image_params *imgp);
static int load_coff_section(struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot);
static int
load_coff_section(struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset,
caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot)
{
size_t map_len;
vm_offset_t map_offset;
vm_offset_t map_addr;
int error;
unsigned char *data_buf = 0;
size_t copy_len;
map_offset = trunc_page(offset);
map_addr = trunc_page((vm_offset_t)vmaddr);
if (memsz > filsz) {
/*
* We have the stupid situation that
* the section is longer than it is on file,
* which means it has zero-filled areas, and
* we have to work for it. Stupid iBCS!
*/
map_len = trunc_page(offset + filsz) - trunc_page(map_offset);
} else {
/*
* The only stuff we care about is on disk, and we
* don't care if we map in more than is really there.
*/
map_len = round_page(offset + filsz) - trunc_page(map_offset);
}
DPRINTF(("%s(%d): vm_mmap(&vmspace->vm_map, &0x%08jx, 0x%x, 0x%x, "
"VM_PROT_ALL, MAP_PRIVATE | MAP_FIXED, OBJT_VNODE, vp, 0x%x)\n",
__FILE__, __LINE__, (uintmax_t)map_addr, map_len, prot,
map_offset));
if ((error = vm_mmap(&vmspace->vm_map,
&map_addr,
map_len,
prot,
VM_PROT_ALL,
MAP_PRIVATE | MAP_FIXED,
OBJT_VNODE,
vp,
map_offset)) != 0)
return error;
if (memsz == filsz) {
/* We're done! */
return 0;
}
/*
* Now we have screwball stuff, to accomodate stupid COFF.
* We have to map the remaining bit of the file into the kernel's
* memory map, allocate some anonymous memory, copy that last
* bit into it, and then we're done. *sigh*
* For clean-up reasons, we actally map in the file last.
*/
copy_len = (offset + filsz) - trunc_page(offset + filsz);
map_addr = trunc_page((vm_offset_t)vmaddr + filsz);
map_len = round_page((vm_offset_t)vmaddr + memsz) - map_addr;
DPRINTF(("%s(%d): vm_map_find(&vmspace->vm_map, NULL, 0, &0x%08jx,0x%x, VMFS_NO_SPACE, VM_PROT_ALL, VM_PROT_ALL, 0)\n", __FILE__, __LINE__, (uintmax_t)map_addr, map_len));
if (map_len != 0) {
error = vm_map_find(&vmspace->vm_map, NULL, 0, &map_addr,
map_len, VMFS_NO_SPACE, VM_PROT_ALL, VM_PROT_ALL, 0);
if (error)
return (vm_mmap_to_errno(error));
}
if ((error = vm_mmap(exec_map,
(vm_offset_t *) &data_buf,
PAGE_SIZE,
VM_PROT_READ,
VM_PROT_READ,
0,
OBJT_VNODE,
vp,
trunc_page(offset + filsz))) != 0)
return error;
error = copyout(data_buf, (caddr_t) map_addr, copy_len);
kmem_free_wakeup(exec_map, (vm_offset_t)data_buf, PAGE_SIZE);
return error;
}
static int
coff_load_file(struct thread *td, char *name)
{
struct proc *p = td->td_proc;
struct vmspace *vmspace = p->p_vmspace;
int error;
struct nameidata nd;
struct vnode *vp;
struct vattr attr;
struct filehdr *fhdr;
struct aouthdr *ahdr;
struct scnhdr *scns;
char *ptr = 0;
int nscns;
unsigned long text_offset = 0, text_address = 0, text_size = 0;
unsigned long data_offset = 0, data_address = 0, data_size = 0;
unsigned long bss_size = 0;
int i, writecount;
NDINIT(&nd, LOOKUP, ISOPEN | LOCKLEAF | FOLLOW | SAVENAME,
UIO_SYSSPACE, name, td);
error = namei(&nd);
if (error)
return error;
vp = nd.ni_vp;
if (vp == NULL)
return ENOEXEC;
error = VOP_GET_WRITECOUNT(vp, &writecount);
if (error != 0)
goto fail;
if (writecount != 0) {
error = ETXTBSY;
goto fail;
}
if ((error = VOP_GETATTR(vp, &attr, td->td_ucred)) != 0)
goto fail;
if ((vp->v_mount->mnt_flag & MNT_NOEXEC)
|| ((attr.va_mode & 0111) == 0)
|| (attr.va_type != VREG))
goto fail;
if (attr.va_size == 0) {
error = ENOEXEC;
goto fail;
}
if ((error = VOP_ACCESS(vp, VEXEC, td->td_ucred, td)) != 0)
goto fail;
if ((error = VOP_OPEN(vp, FREAD, td->td_ucred, td, NULL)) != 0)
goto fail;
/*
* Lose the lock on the vnode. It's no longer needed, and must not
* exist for the pagefault paging to work below.
*/
VOP_UNLOCK(vp, 0);
if ((error = vm_mmap(exec_map,
(vm_offset_t *) &ptr,
PAGE_SIZE,
VM_PROT_READ,
VM_PROT_READ,
0,
OBJT_VNODE,
vp,
0)) != 0)
goto unlocked_fail;
fhdr = (struct filehdr *)ptr;
if (fhdr->f_magic != I386_COFF) {
error = ENOEXEC;
goto dealloc_and_fail;
}
nscns = fhdr->f_nscns;
if ((nscns * sizeof(struct scnhdr)) > PAGE_SIZE) {
/*
* XXX -- just fail. I'm so lazy.
*/
error = ENOEXEC;
goto dealloc_and_fail;
}
ahdr = (struct aouthdr*)(ptr + sizeof(struct filehdr));
scns = (struct scnhdr*)(ptr + sizeof(struct filehdr)
+ sizeof(struct aouthdr));
for (i = 0; i < nscns; i++) {
if (scns[i].s_flags & STYP_NOLOAD)
continue;
else if (scns[i].s_flags & STYP_TEXT) {
text_address = scns[i].s_vaddr;
text_size = scns[i].s_size;
text_offset = scns[i].s_scnptr;
}
else if (scns[i].s_flags & STYP_DATA) {
data_address = scns[i].s_vaddr;
data_size = scns[i].s_size;
data_offset = scns[i].s_scnptr;
} else if (scns[i].s_flags & STYP_BSS) {
bss_size = scns[i].s_size;
}
}
if ((error = load_coff_section(vmspace, vp, text_offset,
(caddr_t)(void *)(uintptr_t)text_address,
text_size, text_size,
VM_PROT_READ | VM_PROT_EXECUTE)) != 0) {
goto dealloc_and_fail;
}
if ((error = load_coff_section(vmspace, vp, data_offset,
(caddr_t)(void *)(uintptr_t)data_address,
data_size + bss_size, data_size,
VM_PROT_ALL)) != 0) {
goto dealloc_and_fail;
}
error = 0;
dealloc_and_fail:
kmem_free_wakeup(exec_map, (vm_offset_t)ptr, PAGE_SIZE);
fail:
VOP_UNLOCK(vp, 0);
unlocked_fail:
NDFREE(&nd, NDF_ONLY_PNBUF);
vrele(nd.ni_vp);
return error;
}
static int
exec_coff_imgact(imgp)
struct image_params *imgp;
{
const struct filehdr *fhdr = (const struct filehdr*)imgp->image_header;
const struct aouthdr *ahdr;
const struct scnhdr *scns;
int i;
struct vmspace *vmspace;
int nscns;
int error;
unsigned long text_offset = 0, text_address = 0, text_size = 0;
unsigned long data_offset = 0, data_address = 0, data_size = 0;
unsigned long bss_size = 0;
vm_offset_t hole;
if (fhdr->f_magic != I386_COFF ||
!(fhdr->f_flags & F_EXEC)) {
DPRINTF(("%s(%d): return -1\n", __FILE__, __LINE__));
return -1;
}
nscns = fhdr->f_nscns;
if ((nscns * sizeof(struct scnhdr)) > PAGE_SIZE) {
/*
* For now, return an error -- need to be able to
* read in all of the section structures.
*/
DPRINTF(("%s(%d): return -1\n", __FILE__, __LINE__));
return -1;
}
ahdr = (const struct aouthdr*)
((const char*)(imgp->image_header) + sizeof(struct filehdr));
imgp->entry_addr = ahdr->entry;
scns = (const struct scnhdr*)
((const char*)(imgp->image_header) + sizeof(struct filehdr) +
sizeof(struct aouthdr));
VOP_UNLOCK(imgp->vp, 0);
error = exec_new_vmspace(imgp, &ibcs2_svr3_sysvec);
if (error)
goto fail;
vmspace = imgp->proc->p_vmspace;
for (i = 0; i < nscns; i++) {
DPRINTF(("i = %d, s_name = %s, s_vaddr = %08lx, "
"s_scnptr = %ld s_size = %lx\n", i, scns[i].s_name,
scns[i].s_vaddr, scns[i].s_scnptr, scns[i].s_size));
if (scns[i].s_flags & STYP_NOLOAD) {
/*
* A section that is not loaded, for whatever
* reason. It takes precedance over other flag
* bits...
*/
continue;
} else if (scns[i].s_flags & STYP_TEXT) {
text_address = scns[i].s_vaddr;
text_size = scns[i].s_size;
text_offset = scns[i].s_scnptr;
} else if (scns[i].s_flags & STYP_DATA) {
/* .data section */
data_address = scns[i].s_vaddr;
data_size = scns[i].s_size;
data_offset = scns[i].s_scnptr;
} else if (scns[i].s_flags & STYP_BSS) {
/* .bss section */
bss_size = scns[i].s_size;
} else if (scns[i].s_flags & STYP_LIB) {
char *buf = 0;
int foff = trunc_page(scns[i].s_scnptr);
int off = scns[i].s_scnptr - foff;
int len = round_page(scns[i].s_size + PAGE_SIZE);
int j;
if ((error = vm_mmap(exec_map,
(vm_offset_t *) &buf,
len,
VM_PROT_READ,
VM_PROT_READ,
MAP_SHARED,
OBJT_VNODE,
imgp->vp,
foff)) != 0) {
error = ENOEXEC;
goto fail;
}
if(scns[i].s_size) {
char *libbuf;
int emul_path_len = strlen(ibcs2_emul_path);
libbuf = malloc(MAXPATHLEN + emul_path_len,
M_TEMP, M_WAITOK);
strcpy(libbuf, ibcs2_emul_path);
for (j = off; j < scns[i].s_size + off;) {
long stroff, nextoff;
char *libname;
nextoff = 4 * *(long *)(buf + j);
stroff = 4 * *(long *)(buf + j + sizeof(long));
libname = buf + j + stroff;
j += nextoff;
DPRINTF(("%s(%d): shared library %s\n",
__FILE__, __LINE__, libname));
strlcpy(&libbuf[emul_path_len], libname, MAXPATHLEN);
error = coff_load_file(
FIRST_THREAD_IN_PROC(imgp->proc), libbuf);
if (error)
error = coff_load_file(
FIRST_THREAD_IN_PROC(imgp->proc),
libname);
if (error) {
printf(
"error %d loading coff shared library %s\n",
error, libname);
break;
}
}
free(libbuf, M_TEMP);
}
kmem_free_wakeup(exec_map, (vm_offset_t)buf, len);
if (error)
goto fail;
}
}
/*
* Map in .text now
*/
DPRINTF(("%s(%d): load_coff_section(vmspace, "
"imgp->vp, %08lx, %08lx, 0x%lx, 0x%lx, 0x%x)\n",
__FILE__, __LINE__, text_offset, text_address,
text_size, text_size, VM_PROT_READ | VM_PROT_EXECUTE));
if ((error = load_coff_section(vmspace, imgp->vp,
text_offset,
(caddr_t)(void *)(uintptr_t)text_address,
text_size, text_size,
VM_PROT_READ | VM_PROT_EXECUTE)) != 0) {
DPRINTF(("%s(%d): error = %d\n", __FILE__, __LINE__, error));
goto fail;
}
/*
* Map in .data and .bss now
*/
DPRINTF(("%s(%d): load_coff_section(vmspace, "
"imgp->vp, 0x%08lx, 0x%08lx, 0x%lx, 0x%lx, 0x%x)\n",
__FILE__, __LINE__, data_offset, data_address,
data_size + bss_size, data_size, VM_PROT_ALL));
if ((error = load_coff_section(vmspace, imgp->vp,
data_offset,
(caddr_t)(void *)(uintptr_t)data_address,
data_size + bss_size, data_size,
VM_PROT_ALL)) != 0) {
DPRINTF(("%s(%d): error = %d\n", __FILE__, __LINE__, error));
goto fail;
}
imgp->interpreted = 0;
imgp->proc->p_sysent = &ibcs2_svr3_sysvec;
vmspace->vm_tsize = round_page(text_size) >> PAGE_SHIFT;
vmspace->vm_dsize = round_page(data_size + bss_size) >> PAGE_SHIFT;
vmspace->vm_taddr = (caddr_t)(void *)(uintptr_t)text_address;
vmspace->vm_daddr = (caddr_t)(void *)(uintptr_t)data_address;
hole = trunc_page((vm_offset_t)vmspace->vm_daddr +
ctob(vmspace->vm_dsize));
DPRINTF(("%s(%d): vm_map_find(&vmspace->vm_map, NULL, 0, &0x%jx, PAGE_SIZE, FALSE, VM_PROT_ALL, VM_PROT_ALL, 0)\n",
__FILE__, __LINE__, (uintmax_t)hole));
DPRINTF(("imgact: error = %d\n", error));
vm_map_find(&vmspace->vm_map, NULL, 0,
(vm_offset_t *)&hole, PAGE_SIZE, VMFS_NO_SPACE,
VM_PROT_ALL, VM_PROT_ALL, 0);
DPRINTF(("IBCS2: start vm_dsize = 0x%x, vm_daddr = 0x%p end = 0x%p\n",
ctob(vmspace->vm_dsize), vmspace->vm_daddr,
ctob(vmspace->vm_dsize) + vmspace->vm_daddr ));
DPRINTF(("%s(%d): returning %d!\n", __FILE__, __LINE__, error));
fail:
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
return (error);
}
/*
* Tell kern_execve.c about it, with a little help from the linker.
*/
static struct execsw coff_execsw = { exec_coff_imgact, "coff" };
EXEC_SET(coff, coff_execsw);