crypto/dso/dso_dlfcn.c

   1 /*
   2  * Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the Apache License 2.0 (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 /*
  11  * We need to do this early, because stdio.h includes the header files that
  12  * handle _GNU_SOURCE and other similar macros.  Defining it later is simply
  13  * too late, because those headers are protected from re- inclusion.
  14  */
  15 #ifndef _GNU_SOURCE
  16 # define _GNU_SOURCE            /* make sure dladdr is declared */
  17 #endif
  18
  19 #include "dso_local.h"
  20 #include "e_os.h"
  21
  22 #ifdef DSO_DLFCN
  23
  24 # ifdef HAVE_DLFCN_H
  25 #  ifdef __osf__
  26 #   define __EXTENSIONS__
  27 #  endif
  28 #  include <dlfcn.h>
  29 #  define HAVE_DLINFO 1
  30 #  if defined(__SCO_VERSION__) || defined(_SCO_ELF) || \
  31      (defined(__osf__) && !defined(RTLD_NEXT))     || \
  32      (defined(__OpenBSD__) && !defined(RTLD_SELF)) || \
  33      defined(__ANDROID__) || defined(__TANDEM)
  34 #   undef HAVE_DLINFO
  35 #  endif
  36 # endif
  37
  38 /* Part of the hack in "dlfcn_load" ... */
  39 # define DSO_MAX_TRANSLATED_SIZE 256
  40
  41 static int dlfcn_load(DSO *dso);
  42 static int dlfcn_unload(DSO *dso);
  43 static DSO_FUNC_TYPE dlfcn_bind_func(DSO *dso, const char *symname);
  44 static char *dlfcn_name_converter(DSO *dso, const char *filename);
  45 static char *dlfcn_merger(DSO *dso, const char *filespec1,
  46                           const char *filespec2);
  47 static int dlfcn_pathbyaddr(void *addr, char *path, int sz);
  48 static void *dlfcn_globallookup(const char *name);
  49
  50 static DSO_METHOD dso_meth_dlfcn = {
  51     "OpenSSL 'dlfcn' shared library method",
  52     dlfcn_load,
  53     dlfcn_unload,
  54     dlfcn_bind_func,
  55     NULL,                       /* ctrl */
  56     dlfcn_name_converter,
  57     dlfcn_merger,
  58     NULL,                       /* init */
  59     NULL,                       /* finish */
  60     dlfcn_pathbyaddr,
  61     dlfcn_globallookup
  62 };
  63
  64 DSO_METHOD *DSO_METHOD_openssl(void)
  65 {
  66     return &dso_meth_dlfcn;
  67 }
  68
  69 /*
  70  * Prior to using the dlopen() function, we should decide on the flag we
  71  * send. There's a few different ways of doing this and it's a messy
  72  * venn-diagram to match up which platforms support what. So as we don't have
  73  * autoconf yet, I'm implementing a hack that could be hacked further
  74  * relatively easily to deal with cases as we find them. Initially this is to
  75  * cope with OpenBSD.
  76  */
  77 # if defined(__OpenBSD__) || defined(__NetBSD__)
  78 #  ifdef DL_LAZY
  79 #   define DLOPEN_FLAG DL_LAZY
  80 #  else
  81 #   ifdef RTLD_NOW
  82 #    define DLOPEN_FLAG RTLD_NOW
  83 #   else
  84 #    define DLOPEN_FLAG 0
  85 #   endif
  86 #  endif
  87 # else
  88 #  define DLOPEN_FLAG RTLD_NOW  /* Hope this works everywhere else */
  89 # endif
  90
  91 /*
  92  * For this DSO_METHOD, our meth_data STACK will contain; (i) the handle
  93  * (void*) returned from dlopen().
  94  */
  95
  96 static int dlfcn_load(DSO *dso)
  97 {
  98     void *ptr = NULL;
  99     /* See applicable comments in dso_dl.c */
 100     char *filename = DSO_convert_filename(dso, NULL);
 101     int flags = DLOPEN_FLAG;
 102     int saveerrno = get_last_sys_error();
 103
 104     if (filename == NULL) {
 105         DSOerr(DSO_F_DLFCN_LOAD, DSO_R_NO_FILENAME);
 106         goto err;
 107     }
 108 # ifdef RTLD_GLOBAL
 109     if (dso->flags & DSO_FLAG_GLOBAL_SYMBOLS)
 110         flags |= RTLD_GLOBAL;
 111 # endif
 112 # ifdef _AIX
 113     if (filename[strlen(filename) - 1] == ')')
 114         flags |= RTLD_MEMBER;
 115 # endif
 116     ptr = dlopen(filename, flags);
 117     if (ptr == NULL) {
 118         DSOerr(DSO_F_DLFCN_LOAD, DSO_R_LOAD_FAILED);
 119         ERR_add_error_data(4, "filename(", filename, "): ", dlerror());
 120         goto err;
 121     }
 122     /*
 123      * Some dlopen() implementations (e.g. solaris) do no preserve errno, even
 124      * on a successful call.
 125      */
 126     set_sys_error(saveerrno);
 127     if (!sk_void_push(dso->meth_data, (char *)ptr)) {
 128         DSOerr(DSO_F_DLFCN_LOAD, DSO_R_STACK_ERROR);
 129         goto err;
 130     }
 131     /* Success */
 132     dso->loaded_filename = filename;
 133     return 1;
 134  err:
 135     /* Cleanup! */
 136     OPENSSL_free(filename);
 137     if (ptr != NULL)
 138         dlclose(ptr);
 139     return 0;
 140 }
 141
 142 static int dlfcn_unload(DSO *dso)
 143 {
 144     void *ptr;
 145     if (dso == NULL) {
 146         DSOerr(DSO_F_DLFCN_UNLOAD, ERR_R_PASSED_NULL_PARAMETER);
 147         return 0;
 148     }
 149     if (sk_void_num(dso->meth_data) < 1)
 150         return 1;
 151     ptr = sk_void_pop(dso->meth_data);
 152     if (ptr == NULL) {
 153         DSOerr(DSO_F_DLFCN_UNLOAD, DSO_R_NULL_HANDLE);
 154         /*
 155          * Should push the value back onto the stack in case of a retry.
 156          */
 157         sk_void_push(dso->meth_data, ptr);
 158         return 0;
 159     }
 160     /* For now I'm not aware of any errors associated with dlclose() */
 161     dlclose(ptr);
 162     return 1;
 163 }
 164
 165 static DSO_FUNC_TYPE dlfcn_bind_func(DSO *dso, const char *symname)
 166 {
 167     void *ptr;
 168     union {
 169         DSO_FUNC_TYPE sym;
 170         void *dlret;
 171     } u;
 172
 173     if ((dso == NULL) || (symname == NULL)) {
 174         DSOerr(DSO_F_DLFCN_BIND_FUNC, ERR_R_PASSED_NULL_PARAMETER);
 175         return NULL;
 176     }
 177     if (sk_void_num(dso->meth_data) < 1) {
 178         DSOerr(DSO_F_DLFCN_BIND_FUNC, DSO_R_STACK_ERROR);
 179         return NULL;
 180     }
 181     ptr = sk_void_value(dso->meth_data, sk_void_num(dso->meth_data) - 1);
 182     if (ptr == NULL) {
 183         DSOerr(DSO_F_DLFCN_BIND_FUNC, DSO_R_NULL_HANDLE);
 184         return NULL;
 185     }
 186     u.dlret = dlsym(ptr, symname);
 187     if (u.dlret == NULL) {
 188         DSOerr(DSO_F_DLFCN_BIND_FUNC, DSO_R_SYM_FAILURE);
 189         ERR_add_error_data(4, "symname(", symname, "): ", dlerror());
 190         return NULL;
 191     }
 192     return u.sym;
 193 }
 194
 195 static char *dlfcn_merger(DSO *dso, const char *filespec1,
 196                           const char *filespec2)
 197 {
 198     char *merged;
 199
 200     if (!filespec1 && !filespec2) {
 201         DSOerr(DSO_F_DLFCN_MERGER, ERR_R_PASSED_NULL_PARAMETER);
 202         return NULL;
 203     }
 204     /*
 205      * If the first file specification is a rooted path, it rules. same goes
 206      * if the second file specification is missing.
 207      */
 208     if (!filespec2 || (filespec1 != NULL && filespec1[0] == '/')) {
 209         merged = OPENSSL_strdup(filespec1);
 210         if (merged == NULL) {
 211             DSOerr(DSO_F_DLFCN_MERGER, ERR_R_MALLOC_FAILURE);
 212             return NULL;
 213         }
 214     }
 215     /*
 216      * If the first file specification is missing, the second one rules.
 217      */
 218     else if (!filespec1) {
 219         merged = OPENSSL_strdup(filespec2);
 220         if (merged == NULL) {
 221             DSOerr(DSO_F_DLFCN_MERGER, ERR_R_MALLOC_FAILURE);
 222             return NULL;
 223         }
 224     } else {
 225         /*
 226          * This part isn't as trivial as it looks.  It assumes that the
 227          * second file specification really is a directory, and makes no
 228          * checks whatsoever.  Therefore, the result becomes the
 229          * concatenation of filespec2 followed by a slash followed by
 230          * filespec1.
 231          */
 232         int spec2len, len;
 233
 234         spec2len = strlen(filespec2);
 235         len = spec2len + strlen(filespec1);
 236
 237         if (spec2len && filespec2[spec2len - 1] == '/') {
 238             spec2len--;
 239             len--;
 240         }
 241         merged = OPENSSL_malloc(len + 2);
 242         if (merged == NULL) {
 243             DSOerr(DSO_F_DLFCN_MERGER, ERR_R_MALLOC_FAILURE);
 244             return NULL;
 245         }
 246         strcpy(merged, filespec2);
 247         merged[spec2len] = '/';
 248         strcpy(&merged[spec2len + 1], filespec1);
 249     }
 250     return merged;
 251 }
 252
 253 static char *dlfcn_name_converter(DSO *dso, const char *filename)
 254 {
 255     char *translated;
 256     int len, rsize, transform;
 257
 258     len = strlen(filename);
 259     rsize = len + 1;
 260     transform = (strstr(filename, "/") == NULL);
 261     if (transform) {
 262         /* We will convert this to "%s.so" or "lib%s.so" etc */
 263         rsize += strlen(DSO_EXTENSION);    /* The length of ".so" */
 264         if ((DSO_flags(dso) & DSO_FLAG_NAME_TRANSLATION_EXT_ONLY) == 0)
 265             rsize += 3;         /* The length of "lib" */
 266     }
 267     translated = OPENSSL_malloc(rsize);
 268     if (translated == NULL) {
 269         DSOerr(DSO_F_DLFCN_NAME_CONVERTER, DSO_R_NAME_TRANSLATION_FAILED);
 270         return NULL;
 271     }
 272     if (transform) {
 273         if ((DSO_flags(dso) & DSO_FLAG_NAME_TRANSLATION_EXT_ONLY) == 0)
 274             sprintf(translated, "lib%s" DSO_EXTENSION, filename);
 275         else
 276             sprintf(translated, "%s" DSO_EXTENSION, filename);
 277     } else
 278         sprintf(translated, "%s", filename);
 279     return translated;
 280 }
 281
 282 # ifdef __sgi
 283 /*-
 284 This is a quote from IRIX manual for dladdr(3c):
 285
 286      <dlfcn.h> does not contain a prototype for dladdr or definition of
 287      Dl_info.  The #include <dlfcn.h>  in the SYNOPSIS line is traditional,
 288      but contains no dladdr prototype and no IRIX library contains an
 289      implementation.  Write your own declaration based on the code below.
 290
 291      The following code is dependent on internal interfaces that are not
 292      part of the IRIX compatibility guarantee; however, there is no future
 293      intention to change this interface, so on a practical level, the code
 294      below is safe to use on IRIX.
 295 */
 296 #  include <rld_interface.h>
 297 #  ifndef _RLD_INTERFACE_DLFCN_H_DLADDR
 298 #   define _RLD_INTERFACE_DLFCN_H_DLADDR
 299 typedef struct Dl_info {
 300     const char *dli_fname;
 301     void *dli_fbase;
 302     const char *dli_sname;
 303     void *dli_saddr;
 304     int dli_version;
 305     int dli_reserved1;
 306     long dli_reserved[4];
 307 } Dl_info;
 308 #  else
 309 typedef struct Dl_info Dl_info;
 310 #  endif
 311 #  define _RLD_DLADDR             14
 312
 313 static int dladdr(void *address, Dl_info *dl)
 314 {
 315     void *v;
 316     v = _rld_new_interface(_RLD_DLADDR, address, dl);
 317     return (int)v;
 318 }
 319 # endif                         /* __sgi */
 320
 321 # ifdef _AIX
 322 /*-
 323  * See IBM's AIX Version 7.2, Technical Reference:
 324  *  Base Operating System and Extensions, Volume 1 and 2
 325  *  https://www.ibm.com/support/knowledgecenter/ssw_aix_72/com.ibm.aix.base/technicalreferences.htm
 326  */
 327 #  include <sys/ldr.h>
 328 #  include <errno.h>
 329 /* ~ 64 * (sizeof(struct ld_info) + _XOPEN_PATH_MAX + _XOPEN_NAME_MAX) */
 330 #  define DLFCN_LDINFO_SIZE 86976
 331 typedef struct Dl_info {
 332     const char *dli_fname;
 333 } Dl_info;
 334 /*
 335  * This dladdr()-implementation will also find the ptrgl (Pointer Glue) virtual
 336  * address of a function, which is just located in the DATA segment instead of
 337  * the TEXT segment.
 338  */
 339 static int dladdr(void *ptr, Dl_info *dl)
 340 {
 341     uintptr_t addr = (uintptr_t)ptr;
 342     unsigned int found = 0;
 343     struct ld_info *ldinfos, *next_ldi, *this_ldi;
 344
 345     if ((ldinfos = OPENSSL_malloc(DLFCN_LDINFO_SIZE)) == NULL) {
 346         errno = ENOMEM;
 347         dl->dli_fname = NULL;
 348         return 0;
 349     }
 350
 351     if ((loadquery(L_GETINFO, (void *)ldinfos, DLFCN_LDINFO_SIZE)) < 0) {
 352         /*-
 353          * Error handling is done through errno and dlerror() reading errno:
 354          *  ENOMEM (ldinfos buffer is too small),
 355          *  EINVAL (invalid flags),
 356          *  EFAULT (invalid ldinfos ptr)
 357          */
 358         OPENSSL_free((void *)ldinfos);
 359         dl->dli_fname = NULL;
 360         return 0;
 361     }
 362     next_ldi = ldinfos;
 363
 364     do {
 365         this_ldi = next_ldi;
 366         if (((addr >= (uintptr_t)this_ldi->ldinfo_textorg)
 367              && (addr < ((uintptr_t)this_ldi->ldinfo_textorg +
 368                          this_ldi->ldinfo_textsize)))
 369             || ((addr >= (uintptr_t)this_ldi->ldinfo_dataorg)
 370                 && (addr < ((uintptr_t)this_ldi->ldinfo_dataorg +
 371                             this_ldi->ldinfo_datasize)))) {
 372             char *buffer, *member;
 373             size_t buffer_sz, member_len;
 374
 375             buffer_sz = strlen(this_ldi->ldinfo_filename) + 1;
 376             member = this_ldi->ldinfo_filename + buffer_sz;
 377             if ((member_len = strlen(member)) > 0)
 378                 buffer_sz += 1 + member_len + 1;
 379             found = 1;
 380             if ((buffer = OPENSSL_malloc(buffer_sz)) != NULL) {
 381                 OPENSSL_strlcpy(buffer, this_ldi->ldinfo_filename, buffer_sz);
 382                 if (member_len > 0) {
 383                     /*
 384                      * Need to respect a possible member name and not just
 385                      * returning the path name in this case. See docs:
 386                      * sys/ldr.h, loadquery() and dlopen()/RTLD_MEMBER.
 387                      */
 388                     OPENSSL_strlcat(buffer, "(", buffer_sz);
 389                     OPENSSL_strlcat(buffer, member, buffer_sz);
 390                     OPENSSL_strlcat(buffer, ")", buffer_sz);
 391                 }
 392                 dl->dli_fname = buffer;
 393             } else {
 394                 errno = ENOMEM;
 395             }
 396         } else {
 397             next_ldi = (struct ld_info *)((uintptr_t)this_ldi +
 398                                           this_ldi->ldinfo_next);
 399         }
 400     } while (this_ldi->ldinfo_next && !found);
 401     OPENSSL_free((void *)ldinfos);
 402     return (found && dl->dli_fname != NULL);
 403 }
 404 # endif                         /* _AIX */
 405
 406 static int dlfcn_pathbyaddr(void *addr, char *path, int sz)
 407 {
 408 # ifdef HAVE_DLINFO
 409     Dl_info dli;
 410     int len;
 411
 412     if (addr == NULL) {
 413         union {
 414             int (*f) (void *, char *, int);
 415             void *p;
 416         } t = {
 417             dlfcn_pathbyaddr
 418         };
 419         addr = t.p;
 420     }
 421
 422     if (dladdr(addr, &dli)) {
 423         len = (int)strlen(dli.dli_fname);
 424         if (sz <= 0) {
 425 #  ifdef _AIX
 426             OPENSSL_free((void *)dli.dli_fname);
 427 #  endif
 428             return len + 1;
 429         }
 430         if (len >= sz)
 431             len = sz - 1;
 432         memcpy(path, dli.dli_fname, len);
 433         path[len++] = 0;
 434 #  ifdef _AIX
 435         OPENSSL_free((void *)dli.dli_fname);
 436 #  endif
 437         return len;
 438     }
 439
 440     ERR_add_error_data(2, "dlfcn_pathbyaddr(): ", dlerror());
 441 # endif
 442     return -1;
 443 }
 444
 445 static void *dlfcn_globallookup(const char *name)
 446 {
 447     void *ret = NULL, *handle = dlopen(NULL, RTLD_LAZY);
 448
 449     if (handle) {
 450         ret = dlsym(handle, name);
 451         dlclose(handle);
 452     }
 453
 454     return ret;
 455 }
 456 #endif                          /* DSO_DLFCN */