sys/kern/imgact_gzip.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@login.dkuug.dk> wrote this file.  As long as you retain this notice you
   5  * can do whatever you want with this stuff. If we meet some day, and you think
   6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   7  * ----------------------------------------------------------------------------
   8  *
   9  * $FreeBSD: src/sys/kern/imgact_gzip.c,v 1.40.2.1 2001/11/03 01:41:08 ps Exp $
  10  *
  11  * This module handles execution of a.out files which have been run through
  12  * "gzip".  This saves diskspace, but wastes cpu-cycles and VM.
  13  *
  14  * TODO:
  15  *      text-segments should be made R/O after being filled
  16  *      is the vm-stuff safe ?
  17  *      should handle the entire header of gzip'ed stuff.
  18  *      inflate isn't quite reentrant yet...
  19  *      error-handling is a mess...
  20  *      so is the rest...
  21  *      tidy up unnecesary includes
  22  */
  23
  24 #include <sys/param.h>
  25 #include <sys/exec.h>
  26 #include <sys/imgact.h>
  27 #include <sys/imgact_aout.h>
  28 #include <sys/kernel.h>
  29 #include <sys/mman.h>
  30 #include <sys/proc.h>
  31 #include <sys/resourcevar.h>
  32 #include <sys/sysent.h>
  33 #include <sys/systm.h>
  34 #include <sys/vnode.h>
  35 #include <sys/inflate.h>
  36
  37 #include <vm/vm.h>
  38 #include <vm/vm_param.h>
  39 #include <sys/lock.h>
  40 #include <vm/pmap.h>
  41 #include <vm/vm_map.h>
  42 #include <vm/vm_kern.h>
  43 #include <vm/vm_extern.h>
  44
  45 struct imgact_gzip {
  46         struct image_params *ip;
  47         struct exec     a_out;
  48         int             error;
  49         int             gotheader;
  50         int             where;
  51         u_char         *inbuf;
  52         u_long          offset;
  53         u_long          output;
  54         u_long          len;
  55         int             idx;
  56         u_long          virtual_offset, file_offset, file_end, bss_size;
  57 };
  58
  59 static int exec_gzip_imgact (struct image_params *imgp);
  60 static int NextByte (void *vp);
  61 static int do_aout_hdr (struct imgact_gzip *);
  62 static int Flush (void *vp, u_char *, u_long siz);
  63
  64 static int
  65 exec_gzip_imgact(struct image_params *imgp)
  66 {
  67         int             error, error2 = 0;
  68         const u_char   *p = (const u_char *) imgp->image_header;
  69         struct imgact_gzip igz;
  70         struct inflate  infl;
  71         struct vmspace *vmspace;
  72
  73         /* If these four are not OK, it isn't a gzip file */
  74         if (p[0] != 0x1f)
  75                 return -1;      /* 0    Simply magic     */
  76         if (p[1] != 0x8b)
  77                 return -1;      /* 1    Simply magic     */
  78         if (p[2] != 0x08)
  79                 return -1;      /* 2    Compression method       */
  80         if (p[9] != 0x03)
  81                 return -1;      /* 9    OS compressed on         */
  82
  83         /*
  84          * If this one contains anything but a comment or a filename marker,
  85          * we don't want to chew on it
  86          */
  87         if (p[3] & ~(0x18))
  88                 return ENOEXEC; /* 3    Flags            */
  89
  90         /* These are of no use to us */
  91         /* 4-7  Timestamp                */
  92         /* 8    Extra flags              */
  93
  94         bzero(&igz, sizeof igz);
  95         bzero(&infl, sizeof infl);
  96         infl.gz_private = (void *) &igz;
  97         infl.gz_input = NextByte;
  98         infl.gz_output = Flush;
  99
 100         igz.ip = imgp;
 101         igz.idx = 10;
 102
 103         if (p[3] & 0x08) {      /* skip a filename */
 104                 while (p[igz.idx++])
 105                         if (igz.idx >= PAGE_SIZE)
 106                                 return ENOEXEC;
 107         }
 108         if (p[3] & 0x10) {      /* skip a comment */
 109                 while (p[igz.idx++])
 110                         if (igz.idx >= PAGE_SIZE)
 111                                 return ENOEXEC;
 112         }
 113         igz.len = imgp->lvap->va_size;
 114
 115         error = inflate(&infl);
 116
 117         /*
 118          * The unzipped file may not even have been long enough to contain
 119          * a header giving Flush() a chance to return error.  Check for this.
 120          */
 121         if ( !igz.gotheader )
 122                 return ENOEXEC;
 123
 124         if ( !error ) {
 125                 vmspace = imgp->proc->p_vmspace;
 126                 error = vm_map_protect(&vmspace->vm_map,
 127                         (vm_offset_t) vmspace->vm_taddr,
 128                         round_page((vm_offset_t)
 129                                    (vmspace->vm_taddr + vmspace->vm_tsize)),
 130                         VM_PROT_READ|VM_PROT_EXECUTE,0);
 131         }
 132
 133         if (igz.inbuf) {
 134                 error2 = vm_map_remove(&kernel_map, (vm_offset_t)igz.inbuf,
 135                                        (vm_offset_t)igz.inbuf + PAGE_SIZE);
 136         }
 137         if (igz.error || error || error2) {
 138                 kprintf("Output=%lu ", igz.output);
 139                 kprintf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
 140                        error, igz.error, error2, igz.where);
 141         }
 142         if (igz.error)
 143                 return igz.error;
 144         if (error)
 145                 return ENOEXEC;
 146         if (error2)
 147                 return error2;
 148         return 0;
 149 }
 150
 151 static int
 152 do_aout_hdr(struct imgact_gzip * gz)
 153 {
 154         int             error;
 155         struct vmspace *vmspace;
 156         vm_offset_t     vmaddr;
 157
 158         /*
 159          * Set file/virtual offset based on a.out variant. We do two cases:
 160          * host byte order and network byte order (for NetBSD compatibility)
 161          */
 162         switch ((int) (gz->a_out.a_magic & 0xffff)) {
 163         case ZMAGIC:
 164                 gz->virtual_offset = 0;
 165                 if (gz->a_out.a_text) {
 166                         gz->file_offset = PAGE_SIZE;
 167                 } else {
 168                         /* Bill's "screwball mode" */
 169                         gz->file_offset = 0;
 170                 }
 171                 break;
 172         case QMAGIC:
 173                 gz->virtual_offset = PAGE_SIZE;
 174                 gz->file_offset = 0;
 175                 break;
 176         default:
 177                 /* NetBSD compatibility */
 178                 switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
 179                 case ZMAGIC:
 180                 case QMAGIC:
 181                         gz->virtual_offset = PAGE_SIZE;
 182                         gz->file_offset = 0;
 183                         break;
 184                 default:
 185                         gz->where = __LINE__;
 186                         return (-1);
 187                 }
 188         }
 189
 190         gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
 191
 192         /*
 193          * Check various fields in header for validity/bounds.
 194          */
 195         if (                    /* entry point must lay with text region */
 196             gz->a_out.a_entry < gz->virtual_offset ||
 197             gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
 198
 199         /* text and data size must each be page rounded */
 200             gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
 201                 gz->where = __LINE__;
 202                 return (-1);
 203         }
 204         /*
 205          * text/data/bss must not exceed limits
 206          */
 207         if (                    /* text can't exceed maximum text size */
 208             gz->a_out.a_text > maxtsiz ||
 209
 210         /* data + bss can't exceed rlimit */
 211             gz->a_out.a_data + gz->bss_size >
 212             gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
 213                 gz->where = __LINE__;
 214                 return (ENOMEM);
 215         }
 216         /* Find out how far we should go */
 217         gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
 218
 219         /*
 220          * Destroy old process VM and create a new one (with a new stack)
 221          */
 222         exec_new_vmspace(gz->ip, NULL);
 223
 224         vmspace = gz->ip->proc->p_vmspace;
 225
 226         vmaddr = gz->virtual_offset;
 227
 228         error = vm_mmap(&vmspace->vm_map,
 229                         &vmaddr,
 230                         gz->a_out.a_text + gz->a_out.a_data,
 231                         VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
 232                         0,
 233                         0,
 234                         NULL);
 235
 236         if (error) {
 237                 gz->where = __LINE__;
 238                 return (error);
 239         }
 240
 241         if (gz->bss_size != 0) {
 242                 /*
 243                  * Allocate demand-zeroed area for uninitialized data.
 244                  * "bss" = 'block started by symbol' - named after the
 245                  * IBM 7090 instruction of the same name.
 246                  */
 247                 vmaddr = gz->virtual_offset + gz->a_out.a_text +
 248                         gz->a_out.a_data;
 249                 error = vm_map_find(&vmspace->vm_map,
 250                                     NULL, NULL,
 251                                     0, &vmaddr, gz->bss_size, PAGE_SIZE,
 252                                     FALSE,
 253                                     VM_MAPTYPE_NORMAL, VM_SUBSYS_IMGACT,
 254                                     VM_PROT_ALL, VM_PROT_ALL, 0);
 255                 if (error) {
 256                         gz->where = __LINE__;
 257                         return (error);
 258                 }
 259         }
 260         /* Fill in process VM information */
 261         vmspace->vm_tsize = gz->a_out.a_text;                   /* in bytes */
 262         vmspace->vm_dsize = gz->a_out.a_data + gz->bss_size;    /* in bytes */
 263         vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
 264         vmspace->vm_daddr = (caddr_t) (uintptr_t)
 265                             (gz->virtual_offset + gz->a_out.a_text);
 266
 267         /* Fill in image_params */
 268         gz->ip->interpreted = 0;
 269         gz->ip->entry_addr = gz->a_out.a_entry;
 270
 271         gz->ip->proc->p_sysent = &aout_sysvec;
 272
 273         return 0;
 274 }
 275
 276 static int
 277 NextByte(void *vp)
 278 {
 279         int             error;
 280         struct imgact_gzip *igz = (struct imgact_gzip *) vp;
 281
 282         if (igz->idx >= igz->len) {
 283                 igz->where = __LINE__;
 284                 return GZ_EOF;
 285         }
 286         if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
 287                 return igz->inbuf[(igz->idx++) - igz->offset];
 288         }
 289         if (igz->inbuf) {
 290                 error = vm_map_remove(&kernel_map, (vm_offset_t)igz->inbuf,
 291                                       (vm_offset_t)igz->inbuf + PAGE_SIZE);
 292                 if (error) {
 293                         igz->where = __LINE__;
 294                         igz->error = error;
 295                         return GZ_EOF;
 296                 }
 297         }
 298         igz->offset = igz->idx & ~PAGE_MASK;
 299
 300         error = vm_mmap(&kernel_map,    /* map */
 301                         (vm_offset_t *) & igz->inbuf,   /* address */
 302                         PAGE_SIZE,      /* size */
 303                         VM_PROT_READ,   /* protection */
 304                         VM_PROT_READ,   /* max protection */
 305                         0,      /* flags */
 306                         (caddr_t) igz->ip->vp,  /* vnode */
 307                         igz->offset,    /* offset */
 308                         NULL);          /* fp */
 309         if (error) {
 310                 igz->where = __LINE__;
 311                 igz->error = error;
 312                 return GZ_EOF;
 313         }
 314         return igz->inbuf[(igz->idx++) - igz->offset];
 315 }
 316
 317 static int
 318 Flush(void *vp, u_char * ptr, u_long siz)
 319 {
 320         struct imgact_gzip *gz = (struct imgact_gzip *) vp;
 321         u_char         *p = ptr, *q;
 322         int             i;
 323
 324         /* First, find a a.out-header */
 325         if (gz->output < sizeof gz->a_out) {
 326                 q = (u_char *) & gz->a_out;
 327                 i = min(siz, sizeof gz->a_out - gz->output);
 328                 bcopy(p, q + gz->output, i);
 329                 gz->output += i;
 330                 p += i;
 331                 siz -= i;
 332                 if (gz->output == sizeof gz->a_out) {
 333                         gz->gotheader = 1;
 334                         i = do_aout_hdr(gz);
 335                         if (i == -1) {
 336                                 if (!gz->where)
 337                                         gz->where = __LINE__;
 338                                 gz->error = ENOEXEC;
 339                                 return ENOEXEC;
 340                         } else if (i) {
 341                                 gz->where = __LINE__;
 342                                 gz->error = i;
 343                                 return ENOEXEC;
 344                         }
 345                         if (gz->file_offset == 0) {
 346                                 q = (u_char *) (uintptr_t) gz->virtual_offset;
 347                                 copyout(&gz->a_out, q, sizeof gz->a_out);
 348                         }
 349                 }
 350         }
 351         /* Skip over zero-padded first PAGE if needed */
 352         if (gz->output < gz->file_offset &&
 353             gz->output + siz > gz->file_offset) {
 354                 i = min(siz, gz->file_offset - gz->output);
 355                 gz->output += i;
 356                 p += i;
 357                 siz -= i;
 358         }
 359         if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
 360                 i = min(siz, gz->file_end - gz->output);
 361                 q = (u_char *) (uintptr_t)
 362                     (gz->virtual_offset + gz->output - gz->file_offset);
 363                 copyout(p, q, i);
 364                 gz->output += i;
 365                 p += i;
 366                 siz -= i;
 367         }
 368         gz->output += siz;
 369         return 0;
 370 }
 371
 372
 373 /*
 374  * Tell kern_execve.c about it, with a little help from the linker.
 375  */
 376 static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
 377 EXEC_SET(execgzip, gzip_execsw);