imgact_gzip.c revision 100384
1/* 2 * ---------------------------------------------------------------------------- 3 * "THE BEER-WARE LICENSE" (Revision 42): 4 * <phk@FreeBSD.org> 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: head/sys/kern/imgact_gzip.c 100384 2002-07-20 02:56:12Z peter $ 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 46struct 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 60static int exec_gzip_imgact(struct image_params *imgp); 61static int NextByte(void *vp); 62static int do_aout_hdr(struct imgact_gzip *); 63static int Flush(void *vp, u_char *, u_long siz); 64 65static int 66exec_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 154static int 155do_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, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS, USRSTACK); 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 285static int 286NextByte(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 325static int 326Flush(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 */ 384static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"}; 385EXEC_SET(execgzip, gzip_execsw); 386