X-Git-Url: https://ncurses.scripts.mit.edu/?a=blobdiff_plain;f=ncurses%2Ftinfo%2Faccess.c;h=2445e0e0090811cdee6dc032774b195679ab4894;hb=81304798ee736c467839c779c9ca5dca48db7bea;hp=44c7e1b2f5d129d366bcaf45341eaadbbbf39eb5;hpb=a8987e73ec254703634802b4f7ee30d3a485524d;p=ncurses.git diff --git a/ncurses/tinfo/access.c b/ncurses/tinfo/access.c index 44c7e1b2..2445e0e0 100644 --- a/ncurses/tinfo/access.c +++ b/ncurses/tinfo/access.c @@ -1,5 +1,6 @@ /**************************************************************************** - * Copyright (c) 1998,2001,2003 Free Software Foundation, Inc. * + * Copyright 2019-2020,2021 Thomas E. Dickey * + * Copyright 1998-2011,2012 Free Software Foundation, Inc. * * * * Permission is hereby granted, free of charge, to any person obtaining a * * copy of this software and associated documentation files (the * @@ -27,31 +28,46 @@ ****************************************************************************/ /**************************************************************************** - * Author: Thomas E. Dickey 1998,2000,2001 * + * Author: Thomas E. Dickey * ****************************************************************************/ #include + +#include + +#ifndef USE_ROOT_ACCESS +#if HAVE_SETFSUID +#include +#else +#include +#endif +#endif + #include -#include -MODULE_ID("$Id: access.c,v 1.10 2003/07/05 19:31:28 tom Exp $") +MODULE_ID("$Id: access.c,v 1.29 2021/06/26 23:50:02 tom Exp $") #define LOWERCASE(c) ((isalpha(UChar(c)) && isupper(UChar(c))) ? tolower(UChar(c)) : (c)) +#ifdef _NC_MSC +# define ACCESS(FN, MODE) access((FN), (MODE)&(R_OK|W_OK)) +#else +# define ACCESS access +#endif + NCURSES_EXPORT(char *) _nc_rootname(char *path) { char *result = _nc_basename(path); -#if !defined(MIXEDCASE_FILENAMES) || defined(PROG_EXT) +#if !MIXEDCASE_FILENAMES || defined(PROG_EXT) static char *temp; char *s; temp = strdup(result); result = temp; -#if !defined(MIXEDCASE_FILENAMES) - int n; +#if !MIXEDCASE_FILENAMES for (s = result; *s != '\0'; ++s) { - *s = LOWERCASE(*s); + *s = (char) LOWERCASE(*s); } #endif #if defined(PROG_EXT) @@ -64,6 +80,21 @@ _nc_rootname(char *path) return result; } +/* + * Check if a string appears to be an absolute pathname. + */ +NCURSES_EXPORT(bool) +_nc_is_abs_path(const char *path) +{ +#if defined(__EMX__) || defined(__DJGPP__) +#define is_pathname(s) ((((s) != 0) && ((s)[0] == '/')) \ + || (((s)[0] != 0) && ((s)[1] == ':'))) +#else +#define is_pathname(s) ((s) != 0 && (s)[0] == '/') +#endif + return is_pathname(path); +} + /* * Return index of the basename */ @@ -79,7 +110,7 @@ _nc_pathlast(const char *path) test = path; else test++; - return (test - path); + return (unsigned) (test - path); } NCURSES_EXPORT(char *) @@ -91,26 +122,87 @@ _nc_basename(char *path) NCURSES_EXPORT(int) _nc_access(const char *path, int mode) { - if (access(path, mode) < 0) { + int result; + + if (path == 0) { + result = -1; + } else if (ACCESS(path, mode) < 0) { if ((mode & W_OK) != 0 && errno == ENOENT && strlen(path) < PATH_MAX) { char head[PATH_MAX]; - char *leaf = _nc_basename(strcpy(head, path)); + char *leaf; + _nc_STRCPY(head, path, sizeof(head)); + leaf = _nc_basename(head); if (leaf == 0) leaf = head; *leaf = '\0'; if (head == leaf) - (void) strcpy(head, "."); + _nc_STRCPY(head, ".", sizeof(head)); - return access(head, R_OK | W_OK | X_OK); + result = ACCESS(head, R_OK | W_OK | X_OK); + } else { + result = -1; } - return -1; + } else { + result = 0; } - return 0; + return result; } +NCURSES_EXPORT(bool) +_nc_is_dir_path(const char *path) +{ + bool result = FALSE; + struct stat sb; + + if (stat(path, &sb) == 0 + && S_ISDIR(sb.st_mode)) { + result = TRUE; + } + return result; +} + +NCURSES_EXPORT(bool) +_nc_is_file_path(const char *path) +{ + bool result = FALSE; + struct stat sb; + + if (stat(path, &sb) == 0 + && S_ISREG(sb.st_mode)) { + result = TRUE; + } + return result; +} + +#if HAVE_ISSETUGID +#define is_elevated() issetugid() +#elif HAVE_GETEUID && HAVE_GETEGID +#define is_elevated() \ + (getuid() != geteuid() \ + || getgid() != getegid()) +#else +#define is_elevated() FALSE +#endif + +#if HAVE_SETFSUID +#define lower_privileges() \ + int save_err = errno; \ + setfsuid(getuid()); \ + setfsgid(getgid()); \ + errno = save_err +#define resume_elevation() \ + save_err = errno; \ + setfsuid(geteuid()); \ + setfsgid(getegid()); \ + errno = save_err +#else +#define lower_privileges() /* nothing */ +#define resume_elevation() /* nothing */ +#endif + #ifndef USE_ROOT_ENVIRON /* * Returns true if we allow application to use environment variables that are @@ -119,14 +211,50 @@ _nc_access(const char *path, int mode) NCURSES_EXPORT(int) _nc_env_access(void) { -#if HAVE_ISSETUGID - if (issetugid()) - return FALSE; -#elif HAVE_GETEUID && HAVE_GETEGID - if (getuid() != geteuid() - || getgid() != getegid()) - return FALSE; + int result = TRUE; + + if (is_elevated()) { + result = FALSE; + } else if ((getuid() != ROOT_UID) && (geteuid() != ROOT_UID)) { + result = FALSE; + } + return result; +} +#endif /* USE_ROOT_ENVIRON */ + +#ifndef USE_ROOT_ACCESS +/* + * Limit privileges if possible; otherwise disallow access for updating files. + */ +NCURSES_EXPORT(FILE *) +_nc_safe_fopen(const char *path, const char *mode) +{ + FILE *result = NULL; +#if HAVE_SETFSUID + lower_privileges(); + result = fopen(path, mode); + resume_elevation(); +#else + if (!is_elevated() || *mode == 'r') { + result = fopen(path, mode); + } #endif - return getuid() != 0 && geteuid() != 0; /* ...finally, disallow root */ + return result; } + +NCURSES_EXPORT(int) +_nc_safe_open3(const char *path, int flags, mode_t mode) +{ + int result = -1; +#if HAVE_SETFSUID + lower_privileges(); + result = open(path, flags, mode); + resume_elevation(); +#else + if (!is_elevated() || (flags & O_RDONLY)) { + result = open(path, flags, mode); + } #endif + return result; +} +#endif /* USE_ROOT_ENVIRON */