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 1.9 2006/12/28 21:24:01 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(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 = vm_map_remove(&kernel_map, (vm_offset_t)igz.inbuf,
 136                                        (vm_offset_t)igz.inbuf + PAGE_SIZE);
 137         }
 138         if (igz.error || error || error2) {
 139                 kprintf("Output=%lu ", igz.output);
 140                 kprintf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
 141                        error, igz.error, error2, igz.where);
 142         }
 143         if (igz.error)
 144                 return igz.error;
 145         if (error)
 146                 return ENOEXEC;
 147         if (error2)
 148                 return error2;
 149         return 0;
 150 }
 151
 152 static int
 153 do_aout_hdr(struct imgact_gzip * gz)
 154 {
 155         int             error;
 156         struct vmspace *vmspace;
 157         vm_offset_t     vmaddr;
 158
 159         /*
 160          * Set file/virtual offset based on a.out variant. We do two cases:
 161          * host byte order and network byte order (for NetBSD compatibility)
 162          */
 163         switch ((int) (gz->a_out.a_magic & 0xffff)) {
 164         case ZMAGIC:
 165                 gz->virtual_offset = 0;
 166                 if (gz->a_out.a_text) {
 167                         gz->file_offset = PAGE_SIZE;
 168                 } else {
 169                         /* Bill's "screwball mode" */
 170                         gz->file_offset = 0;
 171                 }
 172                 break;
 173         case QMAGIC:
 174                 gz->virtual_offset = PAGE_SIZE;
 175                 gz->file_offset = 0;
 176                 break;
 177         default:
 178                 /* NetBSD compatibility */
 179                 switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
 180                 case ZMAGIC:
 181                 case QMAGIC:
 182                         gz->virtual_offset = PAGE_SIZE;
 183                         gz->file_offset = 0;
 184                         break;
 185                 default:
 186                         gz->where = __LINE__;
 187                         return (-1);
 188                 }
 189         }
 190
 191         gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
 192
 193         /*
 194          * Check various fields in header for validity/bounds.
 195          */
 196         if (                    /* entry point must lay with text region */
 197             gz->a_out.a_entry < gz->virtual_offset ||
 198             gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
 199
 200         /* text and data size must each be page rounded */
 201             gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
 202                 gz->where = __LINE__;
 203                 return (-1);
 204         }
 205         /*
 206          * text/data/bss must not exceed limits
 207          */
 208         if (                    /* text can't exceed maximum text size */
 209             gz->a_out.a_text > maxtsiz ||
 210
 211         /* data + bss can't exceed rlimit */
 212             gz->a_out.a_data + gz->bss_size >
 213             gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
 214                 gz->where = __LINE__;
 215                 return (ENOMEM);
 216         }
 217         /* Find out how far we should go */
 218         gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
 219
 220         /*
 221          * Destroy old process VM and create a new one (with a new stack)
 222          */
 223         exec_new_vmspace(gz->ip, NULL);
 224
 225         vmspace = gz->ip->proc->p_vmspace;
 226
 227         vmaddr = gz->virtual_offset;
 228
 229         error = vm_mmap(&vmspace->vm_map,
 230                         &vmaddr,
 231                         gz->a_out.a_text + gz->a_out.a_data,
 232                         VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
 233                         0,
 234                         0);
 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, VM_MAPTYPE_NORMAL,
 253                                     VM_PROT_ALL, VM_PROT_ALL, 0);
 254                 if (error) {
 255                         gz->where = __LINE__;
 256                         return (error);
 257                 }
 258         }
 259         /* Fill in process VM information */
 260         vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
 261         vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
 262         vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
 263         vmspace->vm_daddr = (caddr_t) (uintptr_t)
 264                             (gz->virtual_offset + gz->a_out.a_text);
 265
 266         /* Fill in image_params */
 267         gz->ip->interpreted = 0;
 268         gz->ip->entry_addr = gz->a_out.a_entry;
 269
 270         gz->ip->proc->p_sysent = &aout_sysvec;
 271
 272         return 0;
 273 }
 274
 275 static int
 276 NextByte(void *vp)
 277 {
 278         int             error;
 279         struct imgact_gzip *igz = (struct imgact_gzip *) vp;
 280
 281         if (igz->idx >= igz->len) {
 282                 igz->where = __LINE__;
 283                 return GZ_EOF;
 284         }
 285         if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
 286                 return igz->inbuf[(igz->idx++) - igz->offset];
 287         }
 288         if (igz->inbuf) {
 289                 error = vm_map_remove(&kernel_map, (vm_offset_t)igz->inbuf,
 290                                       (vm_offset_t)igz->inbuf + PAGE_SIZE);
 291                 if (error) {
 292                         igz->where = __LINE__;
 293                         igz->error = error;
 294                         return GZ_EOF;
 295                 }
 296         }
 297         igz->offset = igz->idx & ~PAGE_MASK;
 298
 299         error = vm_mmap(&kernel_map,    /* map */
 300                         (vm_offset_t *) & igz->inbuf,   /* address */
 301                         PAGE_SIZE,      /* size */
 302                         VM_PROT_READ,   /* protection */
 303                         VM_PROT_READ,   /* max protection */
 304                         0,      /* flags */
 305                         (caddr_t) igz->ip->vp,  /* vnode */
 306                         igz->offset);   /* offset */
 307         if (error) {
 308                 igz->where = __LINE__;
 309                 igz->error = error;
 310                 return GZ_EOF;
 311         }
 312         return igz->inbuf[(igz->idx++) - igz->offset];
 313 }
 314
 315 static int
 316 Flush(void *vp, u_char * ptr, u_long siz)
 317 {
 318         struct imgact_gzip *gz = (struct imgact_gzip *) vp;
 319         u_char         *p = ptr, *q;
 320         int             i;
 321
 322         /* First, find a a.out-header */
 323         if (gz->output < sizeof gz->a_out) {
 324                 q = (u_char *) & gz->a_out;
 325                 i = min(siz, sizeof gz->a_out - gz->output);
 326                 bcopy(p, q + gz->output, i);
 327                 gz->output += i;
 328                 p += i;
 329                 siz -= i;
 330                 if (gz->output == sizeof gz->a_out) {
 331                         gz->gotheader = 1;
 332                         i = do_aout_hdr(gz);
 333                         if (i == -1) {
 334                                 if (!gz->where)
 335                                         gz->where = __LINE__;
 336                                 gz->error = ENOEXEC;
 337                                 return ENOEXEC;
 338                         } else if (i) {
 339                                 gz->where = __LINE__;
 340                                 gz->error = i;
 341                                 return ENOEXEC;
 342                         }
 343                         if (gz->file_offset == 0) {
 344                                 q = (u_char *) (uintptr_t) gz->virtual_offset;
 345                                 copyout(&gz->a_out, q, sizeof gz->a_out);
 346                         }
 347                 }
 348         }
 349         /* Skip over zero-padded first PAGE if needed */
 350         if (gz->output < gz->file_offset &&
 351             gz->output + siz > gz->file_offset) {
 352                 i = min(siz, gz->file_offset - gz->output);
 353                 gz->output += i;
 354                 p += i;
 355                 siz -= i;
 356         }
 357         if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
 358                 i = min(siz, gz->file_end - gz->output);
 359                 q = (u_char *) (uintptr_t)
 360                     (gz->virtual_offset + gz->output - gz->file_offset);
 361                 copyout(p, q, i);
 362                 gz->output += i;
 363                 p += i;
 364                 siz -= i;
 365         }
 366         gz->output += siz;
 367         return 0;
 368 }
 369
 370
 371 /*
 372  * Tell kern_execve.c about it, with a little help from the linker.
 373  */
 374 static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
 375 EXEC_SET(execgzip, gzip_execsw);