diff options
Diffstat (limited to 'lib/util/sudo_dso.c')
| -rw-r--r-- | lib/util/sudo_dso.c | 432 |
1 files changed, 432 insertions, 0 deletions
diff --git a/lib/util/sudo_dso.c b/lib/util/sudo_dso.c new file mode 100644 index 0000000..d38fedf --- /dev/null +++ b/lib/util/sudo_dso.c @@ -0,0 +1,432 @@ +/* + * SPDX-License-Identifier: ISC + * + * Copyright (c) 2010, 2012-2014, 2021-2022 Todd C. Miller <Todd.Miller@sudo.ws> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +/* + * This is an open source non-commercial project. Dear PVS-Studio, please check it. + * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com + */ + +#include <config.h> + +#ifdef __linux__ +# include <sys/stat.h> +# include <sys/utsname.h> +#endif + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#if defined(HAVE_SHL_LOAD) +# include <dl.h> +#elif defined(HAVE_DLOPEN) +# include <dlfcn.h> +#endif +#include <errno.h> + +#include "sudo_compat.h" +#include "sudo_dso.h" +#include "sudo_util.h" + +/* + * Pointer for statically compiled symbols. + */ +static struct sudo_preload_table *preload_table; + +void +sudo_dso_preload_table_v1(struct sudo_preload_table *table) +{ + preload_table = table; +} + +#if defined(HAVE_SHL_LOAD) + +# ifndef DYNAMIC_PATH +# define DYNAMIC_PATH 0 +# endif + +void * +sudo_dso_load_v1(const char *path, int mode) +{ + struct sudo_preload_table *pt; + int flags = DYNAMIC_PATH | BIND_VERBOSE; + + if (mode == 0) + mode = SUDO_DSO_LAZY; /* default behavior */ + + /* Check prelinked symbols first. */ + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->path != NULL && strcmp(path, pt->path) == 0) + return pt->handle; + } + } + + /* We don't support SUDO_DSO_GLOBAL or SUDO_DSO_LOCAL yet. */ + if (ISSET(mode, SUDO_DSO_LAZY)) + flags |= BIND_DEFERRED; + if (ISSET(mode, SUDO_DSO_NOW)) + flags |= BIND_IMMEDIATE; + + return (void *)shl_load(path, flags, 0L); +} + +int +sudo_dso_unload_v1(void *handle) +{ + struct sudo_preload_table *pt; + + /* Check prelinked symbols first. */ + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->handle == handle) + return 0; + } + } + + return shl_unload((shl_t)handle); +} + +void * +sudo_dso_findsym_v1(void *vhandle, const char *symbol) +{ + struct sudo_preload_table *pt; + shl_t handle = vhandle; + void *value = NULL; + + /* Check prelinked symbols first. */ + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->handle == handle) { + struct sudo_preload_symbol *sym; + for (sym = pt->symbols; sym->name != NULL; sym++) { + if (strcmp(sym->name, symbol) == 0) + return sym->addr; + } + errno = ENOENT; + return NULL; + } + } + } + + /* + * Note that the behavior of of SUDO_DSO_NEXT and SUDO_DSO_SELF + * differs from most implementations when called from + * a shared library. + */ + if (vhandle == SUDO_DSO_NEXT) { + /* Iterate over all shared libs looking for symbol. */ + shl_t myhandle = PROG_HANDLE; + struct shl_descriptor *desc; + int idx = 0; + + /* Find program's real handle. */ + if (shl_gethandle(PROG_HANDLE, &desc) == 0) + myhandle = desc->handle; + while (shl_get(idx++, &desc) == 0) { + if (desc->handle == myhandle) + continue; + if (shl_findsym(&desc->handle, symbol, TYPE_UNDEFINED, &value) == 0) + break; + } + } else { + if (vhandle == SUDO_DSO_DEFAULT) + handle = NULL; + else if (vhandle == SUDO_DSO_SELF) + handle = PROG_HANDLE; + (void)shl_findsym(&handle, symbol, TYPE_UNDEFINED, &value); + } + + return value; +} + +char * +sudo_dso_strerror_v1(void) +{ + return strerror(errno); +} + +#elif defined(HAVE_DLOPEN) + +# ifndef RTLD_GLOBAL +# define RTLD_GLOBAL 0 +# endif + +/* Default member names for AIX when dlopen()ing an ar (.a) file. */ +# ifdef RTLD_MEMBER +# ifdef __LP64__ +# define SUDO_DSO_MEMBER "shr_64.o" +# else +# define SUDO_DSO_MEMBER "shr.o" +# endif +# endif + +# if defined(__linux__) +/* + * On Linux systems that use multi-arch, the actual DSO may be + * in a machine-specific subdirectory. If the specified path + * contains /lib/ or /libexec/, insert a multi-arch directory + * after it. + */ +static void * +dlopen_multi_arch(const char *path, int flags) +{ + void *ret = NULL; + struct stat sb; + char *newpath; + + /* Only try multi-arch if the original path does not exist. */ + if (stat(path, &sb) == -1 && errno == ENOENT) { + newpath = sudo_stat_multiarch(path, &sb); + if (newpath != NULL) { + ret = dlopen(newpath, flags); + free(newpath); + } + } + return ret; +} +# else +static void * +dlopen_multi_arch(const char *path, int flags) +{ + return NULL; +} +# endif /* __linux__ */ + +void * +sudo_dso_load_v1(const char *path, int mode) +{ + struct sudo_preload_table *pt; + int flags = 0; + void *ret; +# ifdef RTLD_MEMBER + char *cp; + size_t pathlen; +# endif + + /* Check prelinked symbols first. */ + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->path != NULL && strcmp(path, pt->path) == 0) + return pt->handle; + } + } + + /* Map SUDO_DSO_* -> RTLD_* */ + if (ISSET(mode, SUDO_DSO_LAZY)) + SET(flags, RTLD_LAZY); + if (ISSET(mode, SUDO_DSO_NOW)) + SET(flags, RTLD_NOW); + if (ISSET(mode, SUDO_DSO_GLOBAL)) + SET(flags, RTLD_GLOBAL); + if (ISSET(mode, SUDO_DSO_LOCAL)) + SET(flags, RTLD_LOCAL); + +# ifdef RTLD_MEMBER + /* Check for AIX shlib.a(member) syntax and dlopen() with RTLD_MEMBER. */ + pathlen = strlen(path); + if (pathlen > 2 && path[pathlen - 1] == ')') { + cp = strrchr(path, '('); + if (cp != NULL && cp > path + 2 && cp[-2] == '.' && cp[-1] == 'a') { + /* Only for archive files (e.g. sudoers.a). */ + SET(flags, RTLD_MEMBER); + } + } +# endif /* RTLD_MEMBER */ + ret = dlopen(path, flags); +# if defined(RTLD_MEMBER) + /* Special fallback handling for AIX shared objects. */ + if (ret == NULL && !ISSET(flags, RTLD_MEMBER)) { + switch (errno) { + case ENOEXEC: + /* + * If we try to dlopen() an AIX .a file without an explicit member + * it will fail with ENOEXEC. Try again using the default member. + */ + if (pathlen > 2 && strcmp(&path[pathlen - 2], ".a") == 0) { + int len = asprintf(&cp, "%s(%s)", path, SUDO_DSO_MEMBER); + if (len != -1) { + ret = dlopen(cp, flags|RTLD_MEMBER); + free(cp); + } + if (ret == NULL) { + /* Retry with the original path to get the correct error. */ + ret = dlopen(path, flags); + } + } + break; + case ENOENT: + /* + * If the .so file is missing but the .a file exists, try to + * dlopen() the AIX .a file using the .so name as the member. + * This is for compatibility with versions of sudo that use + * SVR4-style shared libs, not AIX-style shared libs. + */ + if (pathlen > 3 && strcmp(&path[pathlen - 3], ".so") == 0) { + int len = asprintf(&cp, "%.*s.a(%s)", (int)(pathlen - 3), + path, sudo_basename(path)); + if (len != -1) { + ret = dlopen(cp, flags|RTLD_MEMBER); + free(cp); + } + if (ret == NULL) { + /* Retry with the original path to get the correct error. */ + ret = dlopen(path, flags); + } + } + break; + } + } +# endif /* RTLD_MEMBER */ + /* On failure, try again with a multi-arch path where possible. */ + if (ret == NULL) + ret = dlopen_multi_arch(path, flags); + + return ret; +} + +int +sudo_dso_unload_v1(void *handle) +{ + struct sudo_preload_table *pt; + + /* Check prelinked symbols first. */ + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->handle == handle) + return 0; + } + } + + return dlclose(handle); +} + +void * +sudo_dso_findsym_v1(void *handle, const char *symbol) +{ + struct sudo_preload_table *pt; + + /* Check prelinked symbols first. */ + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->handle == handle) { + struct sudo_preload_symbol *sym; + for (sym = pt->symbols; sym->name != NULL; sym++) { + if (strcmp(sym->name, symbol) == 0) + return sym->addr; + } + errno = ENOENT; + return NULL; + } + } + } + + /* + * Not all implementations support the special handles. + */ + if (handle == SUDO_DSO_NEXT) { +# ifdef RTLD_NEXT + handle = RTLD_NEXT; +# else + errno = ENOENT; + return NULL; +# endif + } else if (handle == SUDO_DSO_DEFAULT) { +# ifdef RTLD_DEFAULT + handle = RTLD_DEFAULT; +# else + errno = ENOENT; + return NULL; +# endif + } else if (handle == SUDO_DSO_SELF) { +# ifdef RTLD_SELF + handle = RTLD_SELF; +# else + errno = ENOENT; + return NULL; +# endif + } + + return dlsym(handle, symbol); +} + +char * +sudo_dso_strerror_v1(void) +{ + return dlerror(); +} + +#else /* !HAVE_SHL_LOAD && !HAVE_DLOPEN */ + +/* + * Emulate dlopen() using a static list of symbols compiled into sudo. + */ +void * +sudo_dso_load_v1(const char *path, int mode) +{ + struct sudo_preload_table *pt; + + /* Check prelinked symbols first. */ + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->path != NULL && strcmp(path, pt->path) == 0) + return pt->handle; + } + } + return NULL; +} + +int +sudo_dso_unload_v1(void *handle) +{ + struct sudo_preload_table *pt; + + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->handle == handle) + return 0; + } + } + return -1; +} + +void * +sudo_dso_findsym_v1(void *handle, const char *symbol) +{ + struct sudo_preload_table *pt; + + if (preload_table != NULL) { + for (pt = preload_table; pt->handle != NULL; pt++) { + if (pt->handle == handle) { + struct sudo_preload_symbol *sym; + for (sym = pt->symbols; sym->name != NULL; sym++) { + if (strcmp(sym->name, symbol) == 0) + return sym->addr; + } + } + } + } + errno = ENOENT; + return NULL; +} + +char * +sudo_dso_strerror_v1(void) +{ + return strerror(errno); +} +#endif /* !HAVE_SHL_LOAD && !HAVE_DLOPEN */ |