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  * $FreeBSD$
  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/lock.h>
  30 #include <sys/mman.h>
  31 #include <sys/mutex.h>
  32 #include <sys/proc.h>
  33 #include <sys/resourcevar.h>
  34 #include <sys/sysent.h>
  35 #include <sys/systm.h>
  36 #include <sys/vnode.h>
  37 #include <sys/inflate.h>
  38
  39 #include <vm/vm.h>
  40 #include <vm/vm_param.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         mtx_assert(&Giant, MA_OWNED);
 211         if (                    /* text can't exceed maximum text size */
 212             gz->a_out.a_text > maxtsiz ||
 213
 214         /* data + bss can't exceed rlimit */
 215             gz->a_out.a_data + gz->bss_size >
 216             gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
 217                 gz->where = __LINE__;
 218                 return (ENOMEM);
 219         }
 220         /* Find out how far we should go */
 221         gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
 222
 223         /* copy in arguments and/or environment from old process */
 224         error = exec_extract_strings(gz->ip);
 225         if (error) {
 226                 gz->where = __LINE__;
 227                 return (error);
 228         }
 229         /*
 230          * Destroy old process VM and create a new one (with a new stack)
 231          */
 232         exec_new_vmspace(gz->ip);
 233
 234         vmspace = gz->ip->proc->p_vmspace;
 235
 236         vmaddr = gz->virtual_offset;
 237
 238         error = vm_mmap(&vmspace->vm_map,
 239                         &vmaddr,
 240                         gz->a_out.a_text + gz->a_out.a_data,
 241                         VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
 242                         0,
 243                         0);
 244
 245         if (error) {
 246                 gz->where = __LINE__;
 247                 return (error);
 248         }
 249
 250         if (gz->bss_size != 0) {
 251                 /*
 252                  * Allocate demand-zeroed area for uninitialized data.
 253                  * "bss" = 'block started by symbol' - named after the
 254                  * IBM 7090 instruction of the same name.
 255                  */
 256                 vmaddr = gz->virtual_offset + gz->a_out.a_text +
 257                         gz->a_out.a_data;
 258                 error = vm_map_find(&vmspace->vm_map,
 259                                 NULL,
 260                                 0,
 261                                 &vmaddr,
 262                                 gz->bss_size,
 263                                 FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
 264                 if (error) {
 265                         gz->where = __LINE__;
 266                         return (error);
 267                 }
 268         }
 269         /* Fill in process VM information */
 270         vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
 271         vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
 272         vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
 273         vmspace->vm_daddr = (caddr_t) (uintptr_t)
 274                             (gz->virtual_offset + gz->a_out.a_text);
 275
 276         /* Fill in image_params */
 277         gz->ip->interpreted = 0;
 278         gz->ip->entry_addr = gz->a_out.a_entry;
 279
 280         gz->ip->proc->p_sysent = &aout_sysvec;
 281
 282         return 0;
 283 }
 284
 285 static int
 286 NextByte(void *vp)
 287 {
 288         int             error;
 289         struct imgact_gzip *igz = (struct imgact_gzip *) vp;
 290
 291         if (igz->idx >= igz->len) {
 292                 igz->where = __LINE__;
 293                 return GZ_EOF;
 294         }
 295         if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
 296                 return igz->inbuf[(igz->idx++) - igz->offset];
 297         }
 298         if (igz->inbuf) {
 299                 error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
 300                             (vm_offset_t) igz->inbuf + PAGE_SIZE);
 301                 if (error) {
 302                         igz->where = __LINE__;
 303                         igz->error = error;
 304                         return GZ_EOF;
 305                 }
 306         }
 307         igz->offset = igz->idx & ~PAGE_MASK;
 308
 309         error = vm_mmap(kernel_map,     /* map */
 310                         (vm_offset_t *) & igz->inbuf,   /* address */
 311                         PAGE_SIZE,      /* size */
 312                         VM_PROT_READ,   /* protection */
 313                         VM_PROT_READ,   /* max protection */
 314                         0,      /* flags */
 315                         (caddr_t) igz->ip->vp,  /* vnode */
 316                         igz->offset);   /* offset */
 317         if (error) {
 318                 igz->where = __LINE__;
 319                 igz->error = error;
 320                 return GZ_EOF;
 321         }
 322         return igz->inbuf[(igz->idx++) - igz->offset];
 323 }
 324
 325 static int
 326 Flush(void *vp, u_char * ptr, u_long siz)
 327 {
 328         struct imgact_gzip *gz = (struct imgact_gzip *) vp;
 329         u_char         *p = ptr, *q;
 330         int             i;
 331
 332         /* First, find a a.out-header */
 333         if (gz->output < sizeof gz->a_out) {
 334                 q = (u_char *) & gz->a_out;
 335                 i = min(siz, sizeof gz->a_out - gz->output);
 336                 bcopy(p, q + gz->output, i);
 337                 gz->output += i;
 338                 p += i;
 339                 siz -= i;
 340                 if (gz->output == sizeof gz->a_out) {
 341                         gz->gotheader = 1;
 342                         i = do_aout_hdr(gz);
 343                         if (i == -1) {
 344                                 if (!gz->where)
 345                                         gz->where = __LINE__;
 346                                 gz->error = ENOEXEC;
 347                                 return ENOEXEC;
 348                         } else if (i) {
 349                                 gz->where = __LINE__;
 350                                 gz->error = i;
 351                                 return ENOEXEC;
 352                         }
 353                         if (gz->file_offset == 0) {
 354                                 q = (u_char *) (uintptr_t) gz->virtual_offset;
 355                                 copyout(&gz->a_out, q, sizeof gz->a_out);
 356                         }
 357                 }
 358         }
 359         /* Skip over zero-padded first PAGE if needed */
 360         if (gz->output < gz->file_offset &&
 361             gz->output + siz > gz->file_offset) {
 362                 i = min(siz, gz->file_offset - gz->output);
 363                 gz->output += i;
 364                 p += i;
 365                 siz -= i;
 366         }
 367         if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
 368                 i = min(siz, gz->file_end - gz->output);
 369                 q = (u_char *) (uintptr_t)
 370                     (gz->virtual_offset + gz->output - gz->file_offset);
 371                 copyout(p, q, i);
 372                 gz->output += i;
 373                 p += i;
 374                 siz -= i;
 375         }
 376         gz->output += siz;
 377         return 0;
 378 }
 379
 380
 381 /*
 382  * Tell kern_execve.c about it, with a little help from the linker.
 383  */
 384 static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
 385 EXEC_SET(execgzip, gzip_execsw);