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  * $DragonFly: src/sys/kern/imgact_gzip.c,v 1.6 2006/09/11 20:25:01 dillon Exp $
  11  *
  12  * This module handles execution of a.out files which have been run through
  13  * "gzip".  This saves diskspace, but wastes cpu-cycles and VM.
  14  *
  15  * TODO:
  16  *      text-segments should be made R/O after being filled
  17  *      is the vm-stuff safe ?
  18  *      should handle the entire header of gzip'ed stuff.
  19  *      inflate isn't quite reentrant yet...
  20  *      error-handling is a mess...
  21  *      so is the rest...
  22  *      tidy up unnecesary includes
  23  */
  24
  25 #include <sys/param.h>
  26 #include <sys/exec.h>
  27 #include <sys/imgact.h>
  28 #include <sys/imgact_aout.h>
  29 #include <sys/kernel.h>
  30 #include <sys/mman.h>
  31 #include <sys/proc.h>
  32 #include <sys/resourcevar.h>
  33 #include <sys/sysent.h>
  34 #include <sys/systm.h>
  35 #include <sys/vnode.h>
  36 #include <sys/inflate.h>
  37
  38 #include <vm/vm.h>
  39 #include <vm/vm_param.h>
  40 #include <sys/lock.h>
  41 #include <vm/pmap.h>
  42 #include <vm/vm_map.h>
  43 #include <vm/vm_kern.h>
  44 #include <vm/vm_extern.h>
  45
  46 struct imgact_gzip {
  47         struct image_params *ip;
  48         struct exec     a_out;
  49         int             error;
  50         int             gotheader;
  51         int             where;
  52         u_char         *inbuf;
  53         u_long          offset;
  54         u_long          output;
  55         u_long          len;
  56         int             idx;
  57         u_long          virtual_offset, file_offset, file_end, bss_size;
  58 };
  59
  60 static int exec_gzip_imgact (struct image_params *imgp);
  61 static int NextByte (void *vp);
  62 static int do_aout_hdr (struct imgact_gzip *);
  63 static int Flush (void *vp, u_char *, u_long siz);
  64
  65 static int
  66 exec_gzip_imgact(imgp)
  67         struct image_params *imgp;
  68 {
  69         int             error, error2 = 0;
  70         const u_char   *p = (const u_char *) imgp->image_header;
  71         struct imgact_gzip igz;
  72         struct inflate  infl;
  73         struct vmspace *vmspace;
  74
  75         /* If these four are not OK, it isn't a gzip file */
  76         if (p[0] != 0x1f)
  77                 return -1;      /* 0    Simply magic     */
  78         if (p[1] != 0x8b)
  79                 return -1;      /* 1    Simply magic     */
  80         if (p[2] != 0x08)
  81                 return -1;      /* 2    Compression method       */
  82         if (p[9] != 0x03)
  83                 return -1;      /* 9    OS compressed on         */
  84
  85         /*
  86          * If this one contains anything but a comment or a filename marker,
  87          * we don't want to chew on it
  88          */
  89         if (p[3] & ~(0x18))
  90                 return ENOEXEC; /* 3    Flags            */
  91
  92         /* These are of no use to us */
  93         /* 4-7  Timestamp                */
  94         /* 8    Extra flags              */
  95
  96         bzero(&igz, sizeof igz);
  97         bzero(&infl, sizeof infl);
  98         infl.gz_private = (void *) &igz;
  99         infl.gz_input = NextByte;
 100         infl.gz_output = Flush;
 101
 102         igz.ip = imgp;
 103         igz.idx = 10;
 104
 105         if (p[3] & 0x08) {      /* skip a filename */
 106                 while (p[igz.idx++])
 107                         if (igz.idx >= PAGE_SIZE)
 108                                 return ENOEXEC;
 109         }
 110         if (p[3] & 0x10) {      /* skip a comment */
 111                 while (p[igz.idx++])
 112                         if (igz.idx >= PAGE_SIZE)
 113                                 return ENOEXEC;
 114         }
 115         igz.len = imgp->attr->va_size;
 116
 117         error = inflate(&infl);
 118
 119         /*
 120          * The unzipped file may not even have been long enough to contain
 121          * a header giving Flush() a chance to return error.  Check for this.
 122          */
 123         if ( !igz.gotheader )
 124                 return ENOEXEC;
 125
 126         if ( !error ) {
 127                 vmspace = imgp->proc->p_vmspace;
 128                 error = vm_map_protect(&vmspace->vm_map,
 129                         (vm_offset_t) vmspace->vm_taddr,
 130                         (vm_offset_t) (vmspace->vm_taddr +
 131                                       (vmspace->vm_tsize << PAGE_SHIFT)) ,
 132                         VM_PROT_READ|VM_PROT_EXECUTE,0);
 133         }
 134
 135         if (igz.inbuf) {
 136                 error2 =
 137                         vm_map_remove(kernel_map, (vm_offset_t) igz.inbuf,
 138                             (vm_offset_t) igz.inbuf + PAGE_SIZE);
 139         }
 140         if (igz.error || error || error2) {
 141                 printf("Output=%lu ", igz.output);
 142                 printf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
 143                        error, igz.error, error2, igz.where);
 144         }
 145         if (igz.error)
 146                 return igz.error;
 147         if (error)
 148                 return ENOEXEC;
 149         if (error2)
 150                 return error2;
 151         return 0;
 152 }
 153
 154 static int
 155 do_aout_hdr(struct imgact_gzip * gz)
 156 {
 157         int             error;
 158         struct vmspace *vmspace;
 159         vm_offset_t     vmaddr;
 160
 161         /*
 162          * Set file/virtual offset based on a.out variant. We do two cases:
 163          * host byte order and network byte order (for NetBSD compatibility)
 164          */
 165         switch ((int) (gz->a_out.a_magic & 0xffff)) {
 166         case ZMAGIC:
 167                 gz->virtual_offset = 0;
 168                 if (gz->a_out.a_text) {
 169                         gz->file_offset = PAGE_SIZE;
 170                 } else {
 171                         /* Bill's "screwball mode" */
 172                         gz->file_offset = 0;
 173                 }
 174                 break;
 175         case QMAGIC:
 176                 gz->virtual_offset = PAGE_SIZE;
 177                 gz->file_offset = 0;
 178                 break;
 179         default:
 180                 /* NetBSD compatibility */
 181                 switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
 182                 case ZMAGIC:
 183                 case QMAGIC:
 184                         gz->virtual_offset = PAGE_SIZE;
 185                         gz->file_offset = 0;
 186                         break;
 187                 default:
 188                         gz->where = __LINE__;
 189                         return (-1);
 190                 }
 191         }
 192
 193         gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
 194
 195         /*
 196          * Check various fields in header for validity/bounds.
 197          */
 198         if (                    /* entry point must lay with text region */
 199             gz->a_out.a_entry < gz->virtual_offset ||
 200             gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
 201
 202         /* text and data size must each be page rounded */
 203             gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
 204                 gz->where = __LINE__;
 205                 return (-1);
 206         }
 207         /*
 208          * text/data/bss must not exceed limits
 209          */
 210         if (                    /* text can't exceed maximum text size */
 211             gz->a_out.a_text > maxtsiz ||
 212
 213         /* data + bss can't exceed rlimit */
 214             gz->a_out.a_data + gz->bss_size >
 215             gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
 216                 gz->where = __LINE__;
 217                 return (ENOMEM);
 218         }
 219         /* Find out how far we should go */
 220         gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
 221
 222         /*
 223          * Destroy old process VM and create a new one (with a new stack)
 224          */
 225         exec_new_vmspace(gz->ip, NULL);
 226
 227         vmspace = gz->ip->proc->p_vmspace;
 228
 229         vmaddr = gz->virtual_offset;
 230
 231         error = vm_mmap(&vmspace->vm_map,
 232                         &vmaddr,
 233                         gz->a_out.a_text + gz->a_out.a_data,
 234                         VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
 235                         0,
 236                         0);
 237
 238         if (error) {
 239                 gz->where = __LINE__;
 240                 return (error);
 241         }
 242
 243         if (gz->bss_size != 0) {
 244                 /*
 245                  * Allocate demand-zeroed area for uninitialized data.
 246                  * "bss" = 'block started by symbol' - named after the
 247                  * IBM 7090 instruction of the same name.
 248                  */
 249                 vmaddr = gz->virtual_offset + gz->a_out.a_text +
 250                         gz->a_out.a_data;
 251                 error = vm_map_find(&vmspace->vm_map,
 252                                     NULL, 0,
 253                                     &vmaddr, gz->bss_size,
 254                                     FALSE,
 255                                     VM_MAPTYPE_NORMAL,
 256                                     VM_PROT_ALL, VM_PROT_ALL,
 257                                     0);
 258                 if (error) {
 259                         gz->where = __LINE__;
 260                         return (error);
 261                 }
 262         }
 263         /* Fill in process VM information */
 264         vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
 265         vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
 266         vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
 267         vmspace->vm_daddr = (caddr_t) (uintptr_t)
 268                             (gz->virtual_offset + gz->a_out.a_text);
 269
 270         /* Fill in image_params */
 271         gz->ip->interpreted = 0;
 272         gz->ip->entry_addr = gz->a_out.a_entry;
 273
 274         gz->ip->proc->p_sysent = &aout_sysvec;
 275
 276         return 0;
 277 }
 278
 279 static int
 280 NextByte(void *vp)
 281 {
 282         int             error;
 283         struct imgact_gzip *igz = (struct imgact_gzip *) vp;
 284
 285         if (igz->idx >= igz->len) {
 286                 igz->where = __LINE__;
 287                 return GZ_EOF;
 288         }
 289         if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
 290                 return igz->inbuf[(igz->idx++) - igz->offset];
 291         }
 292         if (igz->inbuf) {
 293                 error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
 294                             (vm_offset_t) igz->inbuf + PAGE_SIZE);
 295                 if (error) {
 296                         igz->where = __LINE__;
 297                         igz->error = error;
 298                         return GZ_EOF;
 299                 }
 300         }
 301         igz->offset = igz->idx & ~PAGE_MASK;
 302
 303         error = vm_mmap(kernel_map,     /* map */
 304                         (vm_offset_t *) & igz->inbuf,   /* address */
 305                         PAGE_SIZE,      /* size */
 306                         VM_PROT_READ,   /* protection */
 307                         VM_PROT_READ,   /* max protection */
 308                         0,      /* flags */
 309                         (caddr_t) igz->ip->vp,  /* vnode */
 310                         igz->offset);   /* offset */
 311         if (error) {
 312                 igz->where = __LINE__;
 313                 igz->error = error;
 314                 return GZ_EOF;
 315         }
 316         return igz->inbuf[(igz->idx++) - igz->offset];
 317 }
 318
 319 static int
 320 Flush(void *vp, u_char * ptr, u_long siz)
 321 {
 322         struct imgact_gzip *gz = (struct imgact_gzip *) vp;
 323         u_char         *p = ptr, *q;
 324         int             i;
 325
 326         /* First, find a a.out-header */
 327         if (gz->output < sizeof gz->a_out) {
 328                 q = (u_char *) & gz->a_out;
 329                 i = min(siz, sizeof gz->a_out - gz->output);
 330                 bcopy(p, q + gz->output, i);
 331                 gz->output += i;
 332                 p += i;
 333                 siz -= i;
 334                 if (gz->output == sizeof gz->a_out) {
 335                         gz->gotheader = 1;
 336                         i = do_aout_hdr(gz);
 337                         if (i == -1) {
 338                                 if (!gz->where)
 339                                         gz->where = __LINE__;
 340                                 gz->error = ENOEXEC;
 341                                 return ENOEXEC;
 342                         } else if (i) {
 343                                 gz->where = __LINE__;
 344                                 gz->error = i;
 345                                 return ENOEXEC;
 346                         }
 347                         if (gz->file_offset == 0) {
 348                                 q = (u_char *) (uintptr_t) gz->virtual_offset;
 349                                 copyout(&gz->a_out, q, sizeof gz->a_out);
 350                         }
 351                 }
 352         }
 353         /* Skip over zero-padded first PAGE if needed */
 354         if (gz->output < gz->file_offset &&
 355             gz->output + siz > gz->file_offset) {
 356                 i = min(siz, gz->file_offset - gz->output);
 357                 gz->output += i;
 358                 p += i;
 359                 siz -= i;
 360         }
 361         if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
 362                 i = min(siz, gz->file_end - gz->output);
 363                 q = (u_char *) (uintptr_t)
 364                     (gz->virtual_offset + gz->output - gz->file_offset);
 365                 copyout(p, q, i);
 366                 gz->output += i;
 367                 p += i;
 368                 siz -= i;
 369         }
 370         gz->output += siz;
 371         return 0;
 372 }
 373
 374
 375 /*
 376  * Tell kern_execve.c about it, with a little help from the linker.
 377  */
 378 static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
 379 EXEC_SET(execgzip, gzip_execsw);