05ba50f522
constants VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS, USRSTACK and PS_STRINGS. This is mainly so that they can be variable even for the native abi, based on different machine types. Get stack protections from the sysentvec too. This makes it trivial to map the stack non-executable for certain abis, on machines that support it.
386 lines
9.4 KiB
C
386 lines
9.4 KiB
C
/*
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*
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* This module handles execution of a.out files which have been run through
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* "gzip". This saves diskspace, but wastes cpu-cycles and VM.
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*
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* TODO:
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* text-segments should be made R/O after being filled
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* is the vm-stuff safe ?
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* should handle the entire header of gzip'ed stuff.
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* inflate isn't quite reentrant yet...
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* error-handling is a mess...
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* so is the rest...
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* tidy up unnecesary includes
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*/
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#include <sys/param.h>
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#include <sys/exec.h>
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#include <sys/imgact.h>
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#include <sys/imgact_aout.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mman.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/sysent.h>
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#include <sys/systm.h>
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#include <sys/vnode.h>
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#include <sys/inflate.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_extern.h>
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struct imgact_gzip {
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struct image_params *ip;
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struct exec a_out;
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int error;
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int gotheader;
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int where;
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u_char *inbuf;
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u_long offset;
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u_long output;
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u_long len;
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int idx;
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u_long virtual_offset, file_offset, file_end, bss_size;
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};
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static int exec_gzip_imgact(struct image_params *imgp);
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static int NextByte(void *vp);
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static int do_aout_hdr(struct imgact_gzip *);
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static int Flush(void *vp, u_char *, u_long siz);
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static int
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exec_gzip_imgact(imgp)
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struct image_params *imgp;
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{
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int error, error2 = 0;
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const u_char *p = (const u_char *) imgp->image_header;
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struct imgact_gzip igz;
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struct inflate infl;
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struct vmspace *vmspace;
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/* If these four are not OK, it isn't a gzip file */
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if (p[0] != 0x1f)
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return -1; /* 0 Simply magic */
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if (p[1] != 0x8b)
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return -1; /* 1 Simply magic */
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if (p[2] != 0x08)
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return -1; /* 2 Compression method */
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if (p[9] != 0x03)
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return -1; /* 9 OS compressed on */
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/*
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* If this one contains anything but a comment or a filename marker,
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* we don't want to chew on it
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*/
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if (p[3] & ~(0x18))
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return ENOEXEC; /* 3 Flags */
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/* These are of no use to us */
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/* 4-7 Timestamp */
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/* 8 Extra flags */
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bzero(&igz, sizeof igz);
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bzero(&infl, sizeof infl);
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infl.gz_private = (void *) &igz;
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infl.gz_input = NextByte;
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infl.gz_output = Flush;
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igz.ip = imgp;
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igz.idx = 10;
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if (p[3] & 0x08) { /* skip a filename */
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while (p[igz.idx++])
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if (igz.idx >= PAGE_SIZE)
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return ENOEXEC;
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}
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if (p[3] & 0x10) { /* skip a comment */
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while (p[igz.idx++])
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if (igz.idx >= PAGE_SIZE)
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return ENOEXEC;
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}
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igz.len = imgp->attr->va_size;
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error = inflate(&infl);
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/*
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* The unzipped file may not even have been long enough to contain
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* a header giving Flush() a chance to return error. Check for this.
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*/
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if ( !igz.gotheader )
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return ENOEXEC;
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if ( !error ) {
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vmspace = imgp->proc->p_vmspace;
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error = vm_map_protect(&vmspace->vm_map,
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(vm_offset_t) vmspace->vm_taddr,
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(vm_offset_t) (vmspace->vm_taddr +
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(vmspace->vm_tsize << PAGE_SHIFT)) ,
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VM_PROT_READ|VM_PROT_EXECUTE,0);
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}
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if (igz.inbuf) {
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error2 =
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vm_map_remove(kernel_map, (vm_offset_t) igz.inbuf,
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(vm_offset_t) igz.inbuf + PAGE_SIZE);
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}
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if (igz.error || error || error2) {
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printf("Output=%lu ", igz.output);
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printf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
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error, igz.error, error2, igz.where);
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}
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if (igz.error)
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return igz.error;
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if (error)
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return ENOEXEC;
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if (error2)
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return error2;
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return 0;
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}
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static int
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do_aout_hdr(struct imgact_gzip * gz)
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{
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int error;
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struct vmspace *vmspace;
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vm_offset_t vmaddr;
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/*
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* Set file/virtual offset based on a.out variant. We do two cases:
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* host byte order and network byte order (for NetBSD compatibility)
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*/
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switch ((int) (gz->a_out.a_magic & 0xffff)) {
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case ZMAGIC:
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gz->virtual_offset = 0;
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if (gz->a_out.a_text) {
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gz->file_offset = PAGE_SIZE;
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} else {
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/* Bill's "screwball mode" */
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gz->file_offset = 0;
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}
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break;
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case QMAGIC:
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gz->virtual_offset = PAGE_SIZE;
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gz->file_offset = 0;
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break;
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default:
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/* NetBSD compatibility */
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switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
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case ZMAGIC:
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case QMAGIC:
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gz->virtual_offset = PAGE_SIZE;
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gz->file_offset = 0;
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break;
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default:
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gz->where = __LINE__;
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return (-1);
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}
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}
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gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
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/*
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* Check various fields in header for validity/bounds.
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*/
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if ( /* entry point must lay with text region */
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gz->a_out.a_entry < gz->virtual_offset ||
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gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
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/* text and data size must each be page rounded */
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gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
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gz->where = __LINE__;
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return (-1);
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}
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/*
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* text/data/bss must not exceed limits
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*/
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mtx_assert(&Giant, MA_OWNED);
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if ( /* text can't exceed maximum text size */
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gz->a_out.a_text > maxtsiz ||
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/* data + bss can't exceed rlimit */
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gz->a_out.a_data + gz->bss_size >
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gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
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gz->where = __LINE__;
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return (ENOMEM);
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}
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/* Find out how far we should go */
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gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
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/* copy in arguments and/or environment from old process */
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error = exec_extract_strings(gz->ip);
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if (error) {
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gz->where = __LINE__;
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return (error);
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}
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/*
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* Destroy old process VM and create a new one (with a new stack)
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*/
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exec_new_vmspace(gz->ip, &aout_sysvec);
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vmspace = gz->ip->proc->p_vmspace;
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vmaddr = gz->virtual_offset;
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error = vm_mmap(&vmspace->vm_map,
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&vmaddr,
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gz->a_out.a_text + gz->a_out.a_data,
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VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
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0,
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0);
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if (error) {
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gz->where = __LINE__;
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return (error);
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}
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if (gz->bss_size != 0) {
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/*
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* Allocate demand-zeroed area for uninitialized data.
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* "bss" = 'block started by symbol' - named after the
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* IBM 7090 instruction of the same name.
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*/
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vmaddr = gz->virtual_offset + gz->a_out.a_text +
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gz->a_out.a_data;
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error = vm_map_find(&vmspace->vm_map,
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NULL,
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0,
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&vmaddr,
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gz->bss_size,
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FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
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if (error) {
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gz->where = __LINE__;
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return (error);
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}
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}
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/* Fill in process VM information */
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vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
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vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
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vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
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vmspace->vm_daddr = (caddr_t) (uintptr_t)
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(gz->virtual_offset + gz->a_out.a_text);
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/* Fill in image_params */
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gz->ip->interpreted = 0;
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gz->ip->entry_addr = gz->a_out.a_entry;
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gz->ip->proc->p_sysent = &aout_sysvec;
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return 0;
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}
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static int
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NextByte(void *vp)
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{
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int error;
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struct imgact_gzip *igz = (struct imgact_gzip *) vp;
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if (igz->idx >= igz->len) {
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igz->where = __LINE__;
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return GZ_EOF;
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}
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if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
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return igz->inbuf[(igz->idx++) - igz->offset];
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}
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if (igz->inbuf) {
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error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
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(vm_offset_t) igz->inbuf + PAGE_SIZE);
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if (error) {
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igz->where = __LINE__;
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igz->error = error;
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return GZ_EOF;
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}
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}
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igz->offset = igz->idx & ~PAGE_MASK;
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error = vm_mmap(kernel_map, /* map */
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(vm_offset_t *) & igz->inbuf, /* address */
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PAGE_SIZE, /* size */
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VM_PROT_READ, /* protection */
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VM_PROT_READ, /* max protection */
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0, /* flags */
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(caddr_t) igz->ip->vp, /* vnode */
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igz->offset); /* offset */
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if (error) {
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igz->where = __LINE__;
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igz->error = error;
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return GZ_EOF;
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}
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return igz->inbuf[(igz->idx++) - igz->offset];
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}
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static int
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Flush(void *vp, u_char * ptr, u_long siz)
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{
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struct imgact_gzip *gz = (struct imgact_gzip *) vp;
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u_char *p = ptr, *q;
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int i;
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/* First, find a a.out-header */
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if (gz->output < sizeof gz->a_out) {
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q = (u_char *) & gz->a_out;
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i = min(siz, sizeof gz->a_out - gz->output);
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bcopy(p, q + gz->output, i);
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gz->output += i;
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p += i;
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siz -= i;
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if (gz->output == sizeof gz->a_out) {
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gz->gotheader = 1;
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i = do_aout_hdr(gz);
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if (i == -1) {
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if (!gz->where)
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gz->where = __LINE__;
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gz->error = ENOEXEC;
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return ENOEXEC;
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} else if (i) {
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gz->where = __LINE__;
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gz->error = i;
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return ENOEXEC;
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}
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if (gz->file_offset == 0) {
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q = (u_char *) (uintptr_t) gz->virtual_offset;
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copyout(&gz->a_out, q, sizeof gz->a_out);
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}
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}
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}
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/* Skip over zero-padded first PAGE if needed */
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if (gz->output < gz->file_offset &&
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gz->output + siz > gz->file_offset) {
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i = min(siz, gz->file_offset - gz->output);
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gz->output += i;
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p += i;
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siz -= i;
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}
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if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
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i = min(siz, gz->file_end - gz->output);
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q = (u_char *) (uintptr_t)
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(gz->virtual_offset + gz->output - gz->file_offset);
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copyout(p, q, i);
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gz->output += i;
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p += i;
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siz -= i;
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}
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gz->output += siz;
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return 0;
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}
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/*
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* Tell kern_execve.c about it, with a little help from the linker.
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*/
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static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
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EXEC_SET(execgzip, gzip_execsw);
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