/* * Copyright 2003 Ned Ludd * Copyright 1999-2005 Gentoo Foundation * Distributed under the terms of the GNU General Public License v2 * $Header: /var/cvsroot/gentoo-projects/pax-utils/scanelf.c,v 1.25 2005/04/03 18:56:08 vapier Exp $ * ******************************************************************** * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, * MA 02111-1307, USA. */ #include #include #include #include #include #include #include #include #include #include #include "paxelf.h" static const char *rcsid = "$Id: scanelf.c,v 1.25 2005/04/03 18:56:08 vapier Exp $"; /* helper functions for showing errors */ #define argv0 "scanelf" /*((*argv != NULL) ? argv[0] : __FILE__ "\b\b")*/ #define warn(fmt, args...) \ fprintf(stderr, "%s: " fmt "\n", argv0, ## args) #define warnf(fmt, args...) warn("%s(): " fmt, __FUNCTION__, ## args) #define err(fmt, args...) \ do { \ warn(fmt, ## args); \ exit(EXIT_FAILURE); \ } while (0) /* prototypes */ static void scanelf_file(const char *filename); static void scanelf_dir(const char *path); static void scanelf_ldpath(); static void scanelf_envpath(); static void usage(int status); static void parseargs(int argc, char *argv[]); /* variables to control behavior */ static char scan_ldpath = 0; static char scan_envpath = 0; static char dir_recurse = 0; static char dir_crossmount = 1; static char show_pax = 0; static char show_stack = 0; static char show_textrel = 0; static char show_rpath = 0; static char show_banner = 1; static char be_quiet = 0; static char be_verbose = 0; /* scan an elf file and show all the fun stuff */ static void scanelf_file(const char *filename) { int i; char found_pax, found_stack, found_relro, found_textrel, found_rpath; Elf_Dyn *dyn; elfobj *elf = NULL; found_pax = found_stack = found_relro = found_textrel = found_rpath = 0; /* verify this is real ELF */ if ((elf = readelf(filename)) == NULL) { if (be_verbose > 1) printf("%s: not an ELF\n", filename); return; } if (be_verbose) printf("%s: scanning file\n", filename); /* show the header */ if (!be_quiet && show_banner) { printf(" TYPE "); if (show_pax) printf(" PAX "); if (show_stack) printf(" STK/REL "); if (show_textrel) printf("TEXTREL "); if (show_rpath) printf("RPATH "); printf(" FILE\n"); show_banner = 0; } /* dump all the good stuff */ if (!be_quiet) printf("%-7s ", get_elfetype(elf->ehdr->e_type)); if (show_pax) { char *paxflags = pax_short_hf_flags(PAX_FLAGS(elf)); if (!be_quiet || (be_quiet && strncmp(paxflags, "PeMRxS", 6))) { found_pax = 1; printf("%s ", pax_short_hf_flags(PAX_FLAGS(elf))); } } /* stack fun */ if (show_stack) { for (i = 0; i < elf->ehdr->e_phnum; i++) { if (elf->phdr[i].p_type != PT_GNU_STACK && \ elf->phdr[i].p_type != PT_GNU_RELRO) continue; if (be_quiet && !(elf->phdr[i].p_flags & PF_X)) continue; if (elf->phdr[i].p_type == PT_GNU_STACK) found_stack = 1; if (elf->phdr[i].p_type == PT_GNU_RELRO) found_relro = 1; printf("%s ", gnu_short_stack_flags(elf->phdr[i].p_flags)); } if (!be_quiet && !found_stack) printf("--- "); if (!be_quiet && !found_relro) printf("--- "); } /* textrel fun */ if (show_textrel) { for (i = 0; i < elf->ehdr->e_phnum; i++) { if (elf->phdr[i].p_type != PT_DYNAMIC) continue; dyn = (Elf_Dyn *)(elf->data + elf->phdr[i].p_offset); while (dyn->d_tag != DT_NULL) { if (dyn->d_tag == DT_TEXTREL) { //dyn->d_tag != DT_FLAGS) found_textrel = 1; // if (dyn->d_un.d_val & DF_TEXTREL) printf("TEXTREL "); } ++dyn; } } if (!be_quiet && !found_textrel) printf("------- "); } /* rpath fun */ /* TODO: if be_quiet, only output RPATH's which aren't in /etc/ld.so.conf */ if (show_rpath) { char *rpath, *runpath; Elf_Shdr *strtbl = elf_findsecbyname(elf, ".dynstr"); rpath = runpath = NULL; if (strtbl) for (i = 0; i < elf->ehdr->e_phnum; i++) { if (elf->phdr[i].p_type != PT_DYNAMIC) continue; dyn = (Elf_Dyn *)(elf->data + elf->phdr[i].p_offset); while (dyn->d_tag != DT_NULL) { if (dyn->d_tag == DT_RPATH) { //|| dyn->d_tag != DT_RUNPATH) rpath = elf->data + strtbl->sh_offset + dyn->d_un.d_ptr; found_rpath = 1; } else if (dyn->d_tag == DT_RUNPATH) { runpath = elf->data + strtbl->sh_offset + dyn->d_un.d_ptr; found_rpath = 1; } ++dyn; } } if (rpath && runpath) { if (!strcmp(rpath, runpath)) printf("%-5s ", runpath); else { fprintf(stderr, "%s's RPATH [%s] != RUNPATH [%s]\n", filename, rpath, runpath); printf("{%s,%s} ", rpath, runpath); } } else if (rpath || runpath) printf("%-5s ", (runpath ? runpath : rpath)); else if (!be_quiet && !found_rpath) printf(" - "); } if (!be_quiet || found_pax || found_stack || found_textrel || found_rpath) puts(filename); unreadelf(elf); } /* scan a directory for ET_EXEC files and print when we find one */ static void scanelf_dir(const char *path) { register DIR *dir; register struct dirent *dentry; struct stat st_top, st; char buf[_POSIX_PATH_MAX]; size_t len = 0; /* make sure path exists */ if (lstat(path, &st_top) == -1) return; /* ok, if it isn't a directory, assume we can open it */ if (!S_ISDIR(st_top.st_mode)) { scanelf_file(path); return; } /* now scan the dir looking for fun stuff */ if ((dir = opendir(path)) == NULL) { warnf("could not opendir %s: %s", path, strerror(errno)); return; } if (be_verbose) printf("%s: scanning dir\n", path); while ((dentry = readdir(dir))) { if (!strcmp(dentry->d_name, ".") || !strcmp(dentry->d_name, "..")) continue; len = (strlen(path) + 2 + strlen(dentry->d_name)); assert(len < sizeof(buf)); strncpy(buf, path, len); strncat(buf, "/", len); strncat(buf, dentry->d_name, len); buf[sizeof(buf)] = 0; if (lstat(buf, &st) != -1) { if (S_ISREG(st.st_mode)) scanelf_file(buf); else if (dir_recurse && S_ISDIR(st.st_mode)) { if (dir_crossmount || (st_top.st_dev == st.st_dev)) scanelf_dir(buf); } } } closedir(dir); } /* scan /etc/ld.so.conf for paths */ static void scanelf_ldpath() { char scan_l, scan_ul, scan_ull; char *path, *p; FILE *fp; if ((fp = fopen("/etc/ld.so.conf", "r")) == NULL) err("Unable to open ld.so.conf: %s", strerror(errno)); scan_l = scan_ul = scan_ull = 0; path = malloc(_POSIX_PATH_MAX); while ((fgets(path, _POSIX_PATH_MAX, fp)) != NULL) if (*path == '/') { if ((p = strrchr(path, '\r')) != NULL) *p = 0; if ((p = strrchr(path, '\n')) != NULL) *p = 0; if (!scan_l && !strcmp(path, "/lib")) scan_l = 1; if (!scan_ul && !strcmp(path, "/usr/lib")) scan_ul = 1; if (!scan_ull && !strcmp(path, "/usr/local/lib")) scan_ull = 1; scanelf_dir(path); } free(path); if (!scan_l) scanelf_dir("/lib"); if (!scan_ul) scanelf_dir("/usr/lib"); if (!scan_ull) scanelf_dir("/usr/local/lib"); fclose(fp); } /* scan env PATH for paths */ static void scanelf_envpath() { char *path, *p; path = getenv("PATH"); if (!path) err("PATH is not set in your env !"); if ((path = strdup(path)) == NULL) err("stdup failed: %s", strerror(errno)); while ((p = strrchr(path, ':')) != NULL) { scanelf_dir(p + 1); *p = 0; } free(path); } /* usage / invocation handling functions */ #define PARSE_FLAGS "plRmxetraqvo:BhV" static struct option const long_opts[] = { {"path", no_argument, NULL, 'p'}, {"ldpath", no_argument, NULL, 'l'}, {"recursive", no_argument, NULL, 'R'}, {"mount", no_argument, NULL, 'm'}, {"pax", no_argument, NULL, 'x'}, {"header", no_argument, NULL, 'e'}, {"textrel", no_argument, NULL, 't'}, {"rpath", no_argument, NULL, 'r'}, {"all", no_argument, NULL, 'a'}, {"quiet", no_argument, NULL, 'q'}, {"verbose", no_argument, NULL, 'v'}, {"file",required_argument, NULL, 'o'}, {"nobanner", no_argument, NULL, 'B'}, {"help", no_argument, NULL, 'h'}, {"version", no_argument, NULL, 'V'}, {NULL, no_argument, NULL, 0x0} }; static char *opts_help[] = { "Scan all directories in PATH environment", "Scan all directories in /etc/ld.so.conf", "Scan directories recursively", "Don't recursively cross mount points\n", "Print PaX markings", "Print GNU_STACK markings", "Print TEXTREL information", "Print RPATH information", "Print all scanned info (-x -e -t -r)\n", "Only output 'bad' things", "Be verbose (can be specified more than once)", "Write output stream to a filename", "Don't display the header", "Print this help and exit", "Print version and exit", NULL }; /* display usage and exit */ static void usage(int status) { int i; printf("¤ Scan ELF binaries for stuff\n\n" "Usage: %s [options] [dir2 dirN ...]\n\n", argv0); printf("Options:\n"); for (i = 0; long_opts[i].name; ++i) printf(" -%c, --%-12s× %s\n", long_opts[i].val, long_opts[i].name, opts_help[i]); #ifdef MANLYPAGE for (i = 0; long_opts[i].name; ++i) printf(".TP\n\\fB\\-%c, \\-\\-%s\\fR\n%s\n", long_opts[i].val, long_opts[i].name, opts_help[i]); #endif exit(status); } /* parse command line arguments and preform needed actions */ static void parseargs(int argc, char *argv[]) { int flag; opterr = 0; while ((flag=getopt_long(argc, argv, PARSE_FLAGS, long_opts, NULL)) != -1) { switch (flag) { case 'V': /* version info */ printf("%s compiled %s\n%s\n" "%s written for Gentoo Linux by \n", __FILE__, __DATE__, rcsid, argv0); exit(EXIT_SUCCESS); break; case 's': /* reserved for -s, --symbol= */ case 'h': usage(EXIT_SUCCESS); break; case 'o': { FILE *fp = NULL; fp = freopen(optarg, "w", stdout); if (fp == NULL) err("Could not open output stream '%s': %s", optarg, strerror(errno)); stdout = fp; break; } case 'B': show_banner = 0; break; case 'l': scan_ldpath = 1; break; case 'p': scan_envpath = 1; break; case 'R': dir_recurse = 1; break; case 'm': dir_crossmount = 0; break; case 'x': show_pax = 1; break; case 'e': show_stack = 1; break; case 't': show_textrel = 1; break; case 'r': show_rpath = 1; break; case 'q': be_quiet = 1; break; case 'v': be_verbose = (be_verbose % 20) + 1; break; case 'a': show_pax = show_stack = show_textrel = show_rpath = 1; break; case ':': warn("Option missing parameter"); usage(EXIT_FAILURE); break; case '?': warn("Unknown option"); usage(EXIT_FAILURE); break; default: err("Unhandled option '%c'", flag); break; } } if (be_quiet && be_verbose) err("You can be quiet or you can be verbose, not both, stupid"); if (scan_ldpath) scanelf_ldpath(); if (scan_envpath) scanelf_envpath(); if (optind == argc && !scan_ldpath && !scan_envpath) err("Nothing to scan !?"); while (optind < argc) scanelf_dir(argv[optind++]); } int main(int argc, char *argv[]) { if (argc < 2) usage(EXIT_FAILURE); parseargs(argc, argv); fclose(stdout); return EXIT_SUCCESS; }