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 __P((struct image_params *imgp));
  60 static int NextByte __P((void *vp));
  61 static int do_aout_hdr __P((struct imgact_gzip *));
  62 static int Flush __P((void *vp, u_char *, u_long siz));
  63
  64 static int
  65 exec_gzip_imgact(imgp)
  66         struct image_params *imgp;
  67 {
  68         int             error, error2 = 0;
  69         const u_char   *p = (const u_char *) imgp->image_header;
  70         struct imgact_gzip igz;
  71         struct inflate  infl;
  72         struct vmspace *vmspace;
  73
  74         /* If these four are not OK, it isn't a gzip file */
  75         if (p[0] != 0x1f)
  76                 return -1;      /* 0    Simply magic     */
  77         if (p[1] != 0x8b)
  78                 return -1;      /* 1    Simply magic     */
  79         if (p[2] != 0x08)
  80                 return -1;      /* 2    Compression method       */
  81         if (p[9] != 0x03)
  82                 return -1;      /* 9    OS compressed on         */
  83
  84         /*
  85          * If this one contains anything but a comment or a filename marker,
  86          * we don't want to chew on it
  87          */
  88         if (p[3] & ~(0x18))
  89                 return ENOEXEC; /* 3    Flags            */
  90
  91         /* These are of no use to us */
  92         /* 4-7  Timestamp                */
  93         /* 8    Extra flags              */
  94
  95         bzero(&igz, sizeof igz);
  96         bzero(&infl, sizeof infl);
  97         infl.gz_private = (void *) &igz;
  98         infl.gz_input = NextByte;
  99         infl.gz_output = Flush;
 100
 101         igz.ip = imgp;
 102         igz.idx = 10;
 103
 104         if (p[3] & 0x08) {      /* skip a filename */
 105                 while (p[igz.idx++])
 106                         if (igz.idx >= PAGE_SIZE)
 107                                 return ENOEXEC;
 108         }
 109         if (p[3] & 0x10) {      /* skip a comment */
 110                 while (p[igz.idx++])
 111                         if (igz.idx >= PAGE_SIZE)
 112                                 return ENOEXEC;
 113         }
 114         igz.len = imgp->attr->va_size;
 115
 116         error = inflate(&infl);
 117
 118         /*
 119          * The unzipped file may not even have been long enough to contain
 120          * a header giving Flush() a chance to return error.  Check for this.
 121          */
 122         if ( !igz.gotheader )
 123                 return ENOEXEC;
 124
 125         if ( !error ) {
 126                 vmspace = imgp->proc->p_vmspace;
 127                 error = vm_map_protect(&vmspace->vm_map,
 128                         (vm_offset_t) vmspace->vm_taddr,
 129                         (vm_offset_t) (vmspace->vm_taddr +
 130                                       (vmspace->vm_tsize << PAGE_SHIFT)) ,
 131                         VM_PROT_READ|VM_PROT_EXECUTE,0);
 132         }
 133
 134         if (igz.inbuf) {
 135                 error2 =
 136                         vm_map_remove(kernel_map, (vm_offset_t) igz.inbuf,
 137                             (vm_offset_t) igz.inbuf + PAGE_SIZE);
 138         }
 139         if (igz.error || error || error2) {
 140                 printf("Output=%lu ", igz.output);
 141                 printf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
 142                        error, igz.error, error2, igz.where);
 143         }
 144         if (igz.error)
 145                 return igz.error;
 146         if (error)
 147                 return ENOEXEC;
 148         if (error2)
 149                 return error2;
 150         return 0;
 151 }
 152
 153 static int
 154 do_aout_hdr(struct imgact_gzip * gz)
 155 {
 156         int             error;
 157         struct vmspace *vmspace;
 158         vm_offset_t     vmaddr;
 159
 160         /*
 161          * Set file/virtual offset based on a.out variant. We do two cases:
 162          * host byte order and network byte order (for NetBSD compatibility)
 163          */
 164         switch ((int) (gz->a_out.a_magic & 0xffff)) {
 165         case ZMAGIC:
 166                 gz->virtual_offset = 0;
 167                 if (gz->a_out.a_text) {
 168                         gz->file_offset = PAGE_SIZE;
 169                 } else {
 170                         /* Bill's "screwball mode" */
 171                         gz->file_offset = 0;
 172                 }
 173                 break;
 174         case QMAGIC:
 175                 gz->virtual_offset = PAGE_SIZE;
 176                 gz->file_offset = 0;
 177                 break;
 178         default:
 179                 /* NetBSD compatibility */
 180                 switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
 181                 case ZMAGIC:
 182                 case QMAGIC:
 183                         gz->virtual_offset = PAGE_SIZE;
 184                         gz->file_offset = 0;
 185                         break;
 186                 default:
 187                         gz->where = __LINE__;
 188                         return (-1);
 189                 }
 190         }
 191
 192         gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
 193
 194         /*
 195          * Check various fields in header for validity/bounds.
 196          */
 197         if (                    /* entry point must lay with text region */
 198             gz->a_out.a_entry < gz->virtual_offset ||
 199             gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
 200
 201         /* text and data size must each be page rounded */
 202             gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
 203                 gz->where = __LINE__;
 204                 return (-1);
 205         }
 206         /*
 207          * text/data/bss must not exceed limits
 208          */
 209         if (                    /* text can't exceed maximum text size */
 210             gz->a_out.a_text > maxtsiz ||
 211
 212         /* data + bss can't exceed rlimit */
 213             gz->a_out.a_data + gz->bss_size >
 214             gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
 215                 gz->where = __LINE__;
 216                 return (ENOMEM);
 217         }
 218         /* Find out how far we should go */
 219         gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
 220
 221         /* copy in arguments and/or environment from old process */
 222         error = exec_extract_strings(gz->ip);
 223         if (error) {
 224                 gz->where = __LINE__;
 225                 return (error);
 226         }
 227         /*
 228          * Destroy old process VM and create a new one (with a new stack)
 229          */
 230         exec_new_vmspace(gz->ip);
 231
 232         vmspace = gz->ip->proc->p_vmspace;
 233
 234         vmaddr = gz->virtual_offset;
 235
 236         error = vm_mmap(&vmspace->vm_map,
 237                         &vmaddr,
 238                         gz->a_out.a_text + gz->a_out.a_data,
 239                         VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
 240                         0,
 241                         0);
 242
 243         if (error) {
 244                 gz->where = __LINE__;
 245                 return (error);
 246         }
 247
 248         if (gz->bss_size != 0) {
 249                 /*
 250                  * Allocate demand-zeroed area for uninitialized data.
 251                  * "bss" = 'block started by symbol' - named after the
 252                  * IBM 7090 instruction of the same name.
 253                  */
 254                 vmaddr = gz->virtual_offset + gz->a_out.a_text +
 255                         gz->a_out.a_data;
 256                 error = vm_map_find(&vmspace->vm_map,
 257                                 NULL,
 258                                 0,
 259                                 &vmaddr,
 260                                 gz->bss_size,
 261                                 FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
 262                 if (error) {
 263                         gz->where = __LINE__;
 264                         return (error);
 265                 }
 266         }
 267         /* Fill in process VM information */
 268         vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
 269         vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
 270         vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
 271         vmspace->vm_daddr = (caddr_t) (uintptr_t)
 272                             (gz->virtual_offset + gz->a_out.a_text);
 273
 274         /* Fill in image_params */
 275         gz->ip->interpreted = 0;
 276         gz->ip->entry_addr = gz->a_out.a_entry;
 277
 278         gz->ip->proc->p_sysent = &aout_sysvec;
 279
 280         return 0;
 281 }
 282
 283 static int
 284 NextByte(void *vp)
 285 {
 286         int             error;
 287         struct imgact_gzip *igz = (struct imgact_gzip *) vp;
 288
 289         if (igz->idx >= igz->len) {
 290                 igz->where = __LINE__;
 291                 return GZ_EOF;
 292         }
 293         if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
 294                 return igz->inbuf[(igz->idx++) - igz->offset];
 295         }
 296         if (igz->inbuf) {
 297                 error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
 298                             (vm_offset_t) igz->inbuf + PAGE_SIZE);
 299                 if (error) {
 300                         igz->where = __LINE__;
 301                         igz->error = error;
 302                         return GZ_EOF;
 303                 }
 304         }
 305         igz->offset = igz->idx & ~PAGE_MASK;
 306
 307         error = vm_mmap(kernel_map,     /* map */
 308                         (vm_offset_t *) & igz->inbuf,   /* address */
 309                         PAGE_SIZE,      /* size */
 310                         VM_PROT_READ,   /* protection */
 311                         VM_PROT_READ,   /* max protection */
 312                         0,      /* flags */
 313                         (caddr_t) igz->ip->vp,  /* vnode */
 314                         igz->offset);   /* offset */
 315         if (error) {
 316                 igz->where = __LINE__;
 317                 igz->error = error;
 318                 return GZ_EOF;
 319         }
 320         return igz->inbuf[(igz->idx++) - igz->offset];
 321 }
 322
 323 static int
 324 Flush(void *vp, u_char * ptr, u_long siz)
 325 {
 326         struct imgact_gzip *gz = (struct imgact_gzip *) vp;
 327         u_char         *p = ptr, *q;
 328         int             i;
 329
 330         /* First, find a a.out-header */
 331         if (gz->output < sizeof gz->a_out) {
 332                 q = (u_char *) & gz->a_out;
 333                 i = min(siz, sizeof gz->a_out - gz->output);
 334                 bcopy(p, q + gz->output, i);
 335                 gz->output += i;
 336                 p += i;
 337                 siz -= i;
 338                 if (gz->output == sizeof gz->a_out) {
 339                         gz->gotheader = 1;
 340                         i = do_aout_hdr(gz);
 341                         if (i == -1) {
 342                                 if (!gz->where)
 343                                         gz->where = __LINE__;
 344                                 gz->error = ENOEXEC;
 345                                 return ENOEXEC;
 346                         } else if (i) {
 347                                 gz->where = __LINE__;
 348                                 gz->error = i;
 349                                 return ENOEXEC;
 350                         }
 351                         if (gz->file_offset == 0) {
 352                                 q = (u_char *) (uintptr_t) gz->virtual_offset;
 353                                 copyout(&gz->a_out, q, sizeof gz->a_out);
 354                         }
 355                 }
 356         }
 357         /* Skip over zero-padded first PAGE if needed */
 358         if (gz->output < gz->file_offset &&
 359             gz->output + siz > gz->file_offset) {
 360                 i = min(siz, gz->file_offset - gz->output);
 361                 gz->output += i;
 362                 p += i;
 363                 siz -= i;
 364         }
 365         if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
 366                 i = min(siz, gz->file_end - gz->output);
 367                 q = (u_char *) (uintptr_t)
 368                     (gz->virtual_offset + gz->output - gz->file_offset);
 369                 copyout(p, q, i);
 370                 gz->output += i;
 371                 p += i;
 372                 siz -= i;
 373         }
 374         gz->output += siz;
 375         return 0;
 376 }
 377
 378
 379 /*
 380  * Tell kern_execve.c about it, with a little help from the linker.
 381  */
 382 static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
 383 EXEC_SET(execgzip, gzip_execsw);