Update the ELF image activator to use some of the exec resources rather
than rolling it's own. This means that it now uses the "safe" exec_map_first_page() to get the ld.so headers rather than risking a panic on a page fault failure (eg: NFS server goes down). Since all the ELF tools go to a lot of trouble to make sure everything lives in the first page for executables, this is a win. I have not seen any ELF executable on any system where all the headers didn't fit in the first page with lots of room to spare. I have been running variations of this code for some time on my pure ELF systems.
This commit is contained in:
Peter Wemm
parent
95163bd37f
commit
c8a7999933
@ -35,7 +35,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)machdep.c 7.4 (Berkeley) 6/3/91
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* $Id: machdep.c,v 1.288 1998/02/06 12:13:08 eivind Exp $
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* $Id: machdep.c,v 1.289 1998/02/09 04:45:53 eivind Exp $
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*/
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#include "apm.h"
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@ -354,7 +354,7 @@ cpu_startup(dummy)
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(nswbuf*MAXPHYS) + pager_map_size);
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pager_map->system_map = 1;
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exec_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr,
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(16*(ARG_MAX+PAGE_SIZE)));
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(16*(ARG_MAX+(PAGE_SIZE*3))));
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/*
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* Finally, allocate mbuf pool. Since mclrefcnt is an off-size
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@ -35,7 +35,7 @@
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* SUCH DAMAGE.
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*
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* from: @(#)machdep.c 7.4 (Berkeley) 6/3/91
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* $Id: machdep.c,v 1.288 1998/02/06 12:13:08 eivind Exp $
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* $Id: machdep.c,v 1.289 1998/02/09 04:45:53 eivind Exp $
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*/
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#include "apm.h"
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@ -354,7 +354,7 @@ cpu_startup(dummy)
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(nswbuf*MAXPHYS) + pager_map_size);
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pager_map->system_map = 1;
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exec_map = kmem_suballoc(kernel_map, &minaddr, &maxaddr,
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(16*(ARG_MAX+PAGE_SIZE)));
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(16*(ARG_MAX+(PAGE_SIZE*3))));
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/*
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* Finally, allocate mbuf pool. Since mclrefcnt is an off-size
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@ -26,7 +26,7 @@
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $Id: imgact_elf.c,v 1.20 1997/09/21 03:13:21 peter Exp $
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* $Id: imgact_elf.c,v 1.21 1998/02/09 06:09:21 eivind Exp $
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*/
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#include "opt_rlimit.h"
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@ -62,9 +62,6 @@
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#define MAX_PHDR 32 /* XXX enough ? */
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static int map_pages __P((struct vnode *vp, vm_offset_t offset, vm_offset_t *buf, vm_size_t size));
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static void unmap_pages __P((vm_offset_t buf, vm_size_t size));
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static int elf_check_permissions __P((struct proc *p, struct vnode *vp));
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static int elf_check_header __P((const Elf32_Ehdr *hdr, int type));
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static int elf_load_section __P((struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot));
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static int elf_load_file __P((struct proc *p, char *file, u_long *addr, u_long *entry));
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@ -135,106 +132,6 @@ elf_remove_brand_entry(Elf32_Brandinfo *entry)
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return 0;
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}
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static int
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map_pages(struct vnode *vp, vm_offset_t offset,
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vm_offset_t *buf, vm_size_t size)
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{
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int error;
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vm_offset_t kern_buf;
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vm_size_t pageoff;
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/*
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* The request may not be aligned, and may even cross several
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* page boundaries in the file...
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*/
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pageoff = (offset & PAGE_MASK);
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offset -= pageoff; /* start of first aligned page to map */
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size += pageoff;
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size = round_page(size); /* size of aligned pages to map */
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if (error = vm_mmap(kernel_map,
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&kern_buf,
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size,
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VM_PROT_READ,
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VM_PROT_READ,
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0,
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(caddr_t)vp,
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offset))
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return error;
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*buf = kern_buf + pageoff;
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return 0;
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}
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static void
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unmap_pages(vm_offset_t buf, vm_size_t size)
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{
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vm_size_t pageoff;
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pageoff = (buf & PAGE_MASK);
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buf -= pageoff; /* start of first aligned page to map */
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size += pageoff;
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size = round_page(size);/* size of aligned pages to map */
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vm_map_remove(kernel_map, buf, buf + size);
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}
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static int
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elf_check_permissions(struct proc *p, struct vnode *vp)
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{
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struct vattr attr;
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int error;
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/*
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* Check number of open-for-writes on the file and deny execution
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* if there are any.
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*/
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if (vp->v_writecount) {
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return (ETXTBSY);
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}
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/* Get file attributes */
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error = VOP_GETATTR(vp, &attr, p->p_ucred, p);
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if (error)
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return (error);
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/*
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* 1) Check if file execution is disabled for the filesystem that this
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* file resides on.
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* 2) Insure that at least one execute bit is on - otherwise root
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* will always succeed, and we don't want to happen unless the
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* file really is executable.
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* 3) Insure that the file is a regular file.
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*/
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if ((vp->v_mount->mnt_flag & MNT_NOEXEC) ||
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((attr.va_mode & 0111) == 0) ||
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(attr.va_type != VREG)) {
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return (EACCES);
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}
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/*
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* Zero length files can't be exec'd
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*/
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if (attr.va_size == 0)
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return (ENOEXEC);
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/*
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* Check for execute permission to file based on current credentials.
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* Then call filesystem specific open routine (which does nothing
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* in the general case).
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*/
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error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p);
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if (error)
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return (error);
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error = VOP_OPEN(vp, FREAD, p->p_ucred, p);
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if (error)
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return (error);
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return (0);
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}
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static int
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elf_check_header(const Elf32_Ehdr *hdr, int type)
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{
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@ -298,7 +195,7 @@ elf_load_section(struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset,
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return error;
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}
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if (error = vm_mmap(kernel_map,
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if (error = vm_mmap(exec_map,
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(vm_offset_t *)&data_buf,
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PAGE_SIZE,
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VM_PROT_READ,
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@ -310,7 +207,7 @@ elf_load_section(struct vmspace *vmspace, struct vnode *vp, vm_offset_t offset,
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error = copyout(data_buf, (caddr_t)map_addr, copy_len);
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vm_map_remove(kernel_map, (vm_offset_t)data_buf,
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vm_map_remove(exec_map, (vm_offset_t)data_buf,
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(vm_offset_t)data_buf + PAGE_SIZE);
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/*
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@ -330,12 +227,30 @@ elf_load_file(struct proc *p, char *file, u_long *addr, u_long *entry)
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Elf32_Phdr *phdr = NULL;
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struct nameidata nd;
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struct vmspace *vmspace = p->p_vmspace;
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struct vattr attr;
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struct image_params image_params, *imgp;
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vm_prot_t prot = 0;
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unsigned long text_size = 0, data_size = 0;
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unsigned long text_addr = 0, data_addr = 0;
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int header_size = 0;
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int error, i;
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imgp = &image_params;
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/*
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* Initialize part of the common data
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*/
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imgp->proc = p;
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imgp->uap = NULL;
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imgp->attr = &attr;
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imgp->firstpage = NULL;
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imgp->image_header = (char *)kmem_alloc_wait(exec_map, PAGE_SIZE);
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if (imgp->image_header == NULL) {
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nd.ni_vp = NULL;
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error = ENOMEM;
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goto fail;
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}
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NDINIT(&nd, LOOKUP, LOCKLEAF|FOLLOW, UIO_SYSSPACE, file, p);
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if (error = namei(&nd)) {
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@ -343,28 +258,23 @@ elf_load_file(struct proc *p, char *file, u_long *addr, u_long *entry)
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goto fail;
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}
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imgp->vp = nd.ni_vp;
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/*
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* Check permissions, modes, uid, etc on the file, and "open" it.
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*/
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error = elf_check_permissions(p, nd.ni_vp);
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error = exec_check_permissions(imgp);
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if (error) {
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VOP_UNLOCK(nd.ni_vp, 0, p);
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goto fail;
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}
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/*
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* No longer need this, and it prevents demand paging.
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*/
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error = exec_map_first_page(imgp);
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VOP_UNLOCK(nd.ni_vp, 0, p);
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if (error)
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goto fail;
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/*
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* Map in the header
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*/
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if (error = map_pages(nd.ni_vp, 0, (vm_offset_t *)&hdr, sizeof(hdr)))
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goto fail;
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/*
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* Do we have a valid ELF header ?
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*/
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hdr = (Elf32_Ehdr *)imgp->image_header;
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if (error = elf_check_header(hdr, ET_DYN))
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goto fail;
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@ -379,9 +289,13 @@ elf_load_file(struct proc *p, char *file, u_long *addr, u_long *entry)
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header_size = hdr->e_phentsize * hdr->e_phnum;
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if (error = map_pages(nd.ni_vp, hdr->e_phoff, (vm_offset_t *)&phdr,
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header_size))
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goto fail;
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/* Only support headers that fit within first page for now */
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if (header_size + hdr->e_phoff > PAGE_SIZE) {
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error = ENOEXEC;
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goto fail;
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}
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phdr = (Elf32_Phdr *)(imgp->image_header + hdr->e_phoff);
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for (i = 0; i < hdr->e_phnum; i++) {
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switch(phdr[i].p_type) {
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@ -453,10 +367,11 @@ elf_load_file(struct proc *p, char *file, u_long *addr, u_long *entry)
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}
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fail:
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if (phdr)
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unmap_pages((vm_offset_t)phdr, header_size);
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if (hdr)
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unmap_pages((vm_offset_t)hdr, sizeof(hdr));
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if (imgp->firstpage)
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exec_unmap_first_page(imgp);
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if (imgp->image_header)
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kmem_free_wakeup(exec_map, (vm_offset_t)imgp->image_header,
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PAGE_SIZE);
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if (nd.ni_vp)
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vrele(nd.ni_vp);
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@ -474,8 +389,8 @@ exec_elf_imgact(struct image_params *imgp)
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u_long text_size = 0, data_size = 0;
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u_long text_addr = 0, data_addr = 0;
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u_long addr, entry = 0, proghdr = 0;
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int error, i, header_size = 0, interp_len = 0;
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char *interp = NULL;
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int error, i, header_size = 0;
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const char *interp = NULL;
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char *brand = NULL;
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char path[MAXPATHLEN];
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@ -502,17 +417,8 @@ exec_elf_imgact(struct image_params *imgp)
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if ((hdr->e_phoff > PAGE_SIZE) ||
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(hdr->e_phoff + header_size) > PAGE_SIZE) {
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/*
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* Ouch ! we only get one page full of header...
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* Try to map it in ourselves, and see how we go.
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*/
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if (error = map_pages(imgp->vp, hdr->e_phoff,
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(vm_offset_t *)&mapped_phdr, header_size))
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return (error);
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/*
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* Save manual mapping for cleanup
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*/
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phdr = mapped_phdr;
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/* Only support headers in first page for now */
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return ENOEXEC;
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} else {
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phdr = (const Elf32_Phdr*)
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((const char *)imgp->image_header + hdr->e_phoff);
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@ -581,14 +487,12 @@ exec_elf_imgact(struct image_params *imgp)
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break;
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case PT_INTERP: /* Path to interpreter */
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UPRINTF ("ELF PT_INTERP section ");
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if (phdr[i].p_filesz > MAXPATHLEN) {
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if (phdr[i].p_filesz > MAXPATHLEN ||
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phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE) {
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error = ENOEXEC;
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goto fail;
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}
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interp_len = MAXPATHLEN;
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if (error = map_pages(imgp->vp, phdr[i].p_offset,
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(vm_offset_t *)&interp, interp_len))
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goto fail;
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interp = imgp->image_header + phdr[i].p_offset;
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UPRINTF("<%s>\n", interp);
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break;
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case PT_NOTE: /* Note section */
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@ -697,11 +601,6 @@ exec_elf_imgact(struct image_params *imgp)
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imgp->vp->v_flag |= VTEXT;
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fail:
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if (mapped_phdr)
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unmap_pages((vm_offset_t)mapped_phdr, header_size);
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if (interp)
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unmap_pages((vm_offset_t)interp, interp_len);
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return error;
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}
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@ -23,7 +23,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: kern_exec.c,v 1.77 1998/02/06 12:13:23 eivind Exp $
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* $Id: kern_exec.c,v 1.78 1998/02/25 13:08:06 bde Exp $
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*/
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#include <sys/param.h>
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@ -65,10 +65,6 @@
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static int *exec_copyout_strings __P((struct image_params *));
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static int exec_check_permissions __P((struct image_params *));
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static int exec_map_first_page __P((struct image_params *));
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static void exec_unmap_first_page __P((struct image_params *));
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/*
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* XXX trouble here if sizeof(caddr_t) != sizeof(int), other parts
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* of the sysctl code also assumes this, and sizeof(int) == sizeof(long).
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@ -107,7 +103,6 @@ execve(p, uap)
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int error, len, i;
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struct image_params image_params, *imgp;
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struct vattr attr;
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struct buf *bp = NULL;
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imgp = &image_params;
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@ -645,7 +640,7 @@ exec_copyout_strings(imgp)
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* Check permissions of file to execute.
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* Return 0 for success or error code on failure.
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*/
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static int
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int
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exec_check_permissions(imgp)
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struct image_params *imgp;
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{
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@ -36,7 +36,7 @@
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* SUCH DAMAGE.
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*
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* @(#)exec.h 8.3 (Berkeley) 1/21/94
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* $Id: exec.h,v 1.16 1997/09/07 05:27:08 bde Exp $
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* $Id: exec.h,v 1.17 1997/09/16 11:44:04 bde Exp $
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*/
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#ifndef _SYS_EXEC_H_
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@ -73,4 +73,11 @@ struct execsw {
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#include <machine/exec.h>
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#ifdef KERNEL
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#include <sys/cdefs.h>
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int exec_map_first_page __P((struct image_params *));
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void exec_unmap_first_page __P((struct image_params *));
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#endif
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#endif
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@ -30,7 +30,7 @@
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
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* SUCH DAMAGE.
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*
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* $Id: imgact.h,v 1.15 1997/04/23 22:02:37 ache Exp $
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* $Id: imgact.h,v 1.16 1998/01/11 21:34:43 dyson Exp $
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*/
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#ifndef _SYS_IMGACT_H_
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@ -56,6 +56,7 @@ struct image_params {
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};
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#ifdef KERNEL
|
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int exec_check_permissions __P((struct image_params *));
|
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int exec_extract_strings __P((struct image_params *));
|
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int exec_new_vmspace __P((struct image_params *));
|
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#endif
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