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https://github.com/jart/cosmopolitan.git
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f94c11d978
The ape loader now passes the program executable name directly as a register. `x2` is used on aarch64, `%rdx` on x86_64. This is passed as the third argument to `cosmo()` (M1) or `Launch` (non-M1) and is assigned to the global `__program_executable_name`. `GetProgramExecutableName` now returns this global's value, setting it if it is initially null. `InitProgramExecutableName` first tries exotic, secure methods: `KERN_PROC_PATHNAME` on FreeBSD/NetBSD, and `/proc` on Linux. If those produce a reasonable response (i.e., not `"/usr/bin/ape"`, which happens with the loader before this change), that is used. Otherwise, if `issetugid()`, the empty string is used. Otherwise, the old argv/envp parsing code is run. The value returned from the loader is always the full absolute path of the binary to be executed, having passed through `realpath`. For the non-M1 loader, this necessitated writing `RealPath`, which uses `readlinkat` of `"/proc/self/fd/[progfd]"` on Linux, `F_GETPATH` on Xnu, and the `__realpath` syscall on OpenBSD. On FreeBSD/NetBSD, it punts to `GetProgramExecutableName`, which is secure on those OSes. With the loader, all platforms now have a secure program executable name. With no loader or an old loader, everything still works as it did, but setuid/setgid is not supported if the insecure pathfinding code would have been needed. Fixes #991.
112 lines
4.3 KiB
C
112 lines
4.3 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2023 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/dce.h"
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#include "libc/limits.h"
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#include "libc/runtime/runtime.h"
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#include "libc/stdio/stdio.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/o.h"
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#include "libc/testlib/ezbench.h"
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#include "libc/testlib/subprocess.h"
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#include "libc/testlib/testlib.h"
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static char *self;
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void SetUpOnce(void) {
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self = GetProgramExecutableName();
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testlib_enable_tmp_setup_teardown();
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}
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__attribute__((__constructor__)) static void Child(int argc, char *argv[]) {
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static bool skiparg0tests;
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if (!__program_executable_name && !IsFreebsd() && !IsNetbsd()) {
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skiparg0tests = true;
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if (argc < 2) {
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fprintf(stderr, "warning: old/no loader; skipping argv[0] tests\n");
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}
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}
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if (argc >= 2 && !strcmp(argv[1], "Child")) {
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ASSERT_EQ(argc, 4);
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EXPECT_STREQ(argv[2], GetProgramExecutableName());
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if (!skiparg0tests) {
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EXPECT_STREQ(argv[3], argv[0]);
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}
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exit(g_testlib_failed);
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}
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}
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TEST(GetProgramExecutableName, ofThisFile) {
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EXPECT_EQ('/', *self);
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EXPECT_TRUE(
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endswith(self, "test/libc/calls/getprogramexecutablename_test.com"));
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}
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TEST(GetProgramExecutableName, nullEnv) {
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SPAWN(fork);
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execve(self, (char *[]){self, "Child", self, self, 0}, (char *[]){0});
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abort();
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EXITS(0);
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}
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TEST(GetProramExecutableName, weirdArgv0NullEnv) {
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SPAWN(fork);
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execve(self, (char *[]){"hello", "Child", self, "hello", 0}, (char *[]){0});
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abort();
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EXITS(0);
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}
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TEST(GetProgramExecutableName, weirdArgv0CosmoVar) {
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char buf[32 + PATH_MAX];
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stpcpy(stpcpy(buf, "COSMOPOLITAN_PROGRAM_EXECUTABLE="), self);
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SPAWN(fork);
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execve(self, (char *[]){"hello", "Child", self, "hello", 0},
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(char *[]){buf, 0});
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abort();
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EXITS(0);
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}
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TEST(GetProgramExecutableName, weirdArgv0WrongCosmoVar) {
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char *bad = "COSMOPOLITAN_PROGRAM_EXECUTABLE=hi";
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SPAWN(fork);
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execve(self, (char *[]){"hello", "Child", self, "hello", 0},
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(char *[]){bad, 0});
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abort();
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EXITS(0);
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}
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TEST(GetProgramExecutableName, movedSelf) {
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char buf[BUFSIZ];
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ASSERT_SYS(0, 3, open(GetProgramExecutableName(), O_RDONLY));
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ASSERT_SYS(0, 4, creat("test", 0755));
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ssize_t rc;
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while ((rc = read(3, buf, BUFSIZ)) > 0) {
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ASSERT_SYS(0, rc, write(4, buf, rc));
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}
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ASSERT_EQ(0, rc);
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ASSERT_SYS(0, 0, close(4));
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ASSERT_SYS(0, 0, close(3));
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ASSERT_NE(NULL, getcwd(buf, BUFSIZ - 5));
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stpcpy(buf + strlen(buf), "/test");
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SPAWN(fork);
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execve(buf, (char *[]){"hello", "Child", buf, "hello", 0}, (char *[]){0});
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abort();
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EXITS(0);
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}
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