mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-05-28 08:12:28 +00:00
Validate privileged code relationships
- Work towards improving non-optimized build support - Introduce MODE=zero which is -O0 without ASAN/UBSAN - Use system GCC when ~/.cosmo.mk has USE_SYSTEM_TOOLCHAIN=1 - Have package.com check .privileged code doesn't call non-privileged
This commit is contained in:
Justine Tunney
parent
01fd655097
commit
daf4454a06
82 changed files with 808 additions and 850 deletions
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@ -16,6 +16,7 @@
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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/assert.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/struct/stat.h"
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#include "libc/dce.h"
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@ -26,9 +27,11 @@
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#include "libc/elf/struct/sym.h"
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#include "libc/errno.h"
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#include "libc/fmt/itoa.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/log/check.h"
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#include "libc/log/log.h"
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#include "libc/macros.internal.h"
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#include "libc/mem/gc.internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/map.h"
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@ -41,20 +44,21 @@
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* @fileoverview GCC Codegen Fixer-Upper.
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*/
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#define GETOPTS "h"
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#define GETOPTS "ch"
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#define USAGE \
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"\
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Usage: fixupobj.com [-h] ARGS...\n\
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-?\n\
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-h show help\n\
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-c check-only mode\n\
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"
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#define COSMO_TLS_REG 28
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#define MRS_TPIDR_EL0 0xd53bd040u
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#define MOV_REG(DST, SRC) (0xaa0003e0u | (SRC) << 16 | (DST))
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static const unsigned char kFatNops[8][8] = {
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const unsigned char kFatNops[8][8] = {
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{}, //
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{0x90}, // nop
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{0x66, 0x90}, // xchg %ax,%ax
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@ -65,31 +69,43 @@ static const unsigned char kFatNops[8][8] = {
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{0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00}, // nopl 0x00000000(%rax)
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};
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void Write(const char *s, ...) {
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int mode;
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char *symstrs;
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char *secstrs;
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ssize_t esize;
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Elf64_Sym *syms;
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const char *epath;
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Elf64_Xword symcount;
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const Elf64_Ehdr *elf;
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void Print(int fd, const char *s, ...) {
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va_list va;
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char buf[2048];
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va_start(va, s);
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buf[0] = 0;
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do {
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write(2, s, strlen(s));
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strlcat(buf, s, sizeof(buf));
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} while ((s = va_arg(va, const char *)));
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strlcat(buf, "\n", sizeof(buf));
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write(fd, buf, strlen(buf));
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va_end(va);
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}
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wontreturn void SysExit(int rc, const char *call, const char *thing) {
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int err;
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char ibuf[12];
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const char *estr;
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err = errno;
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FormatInt32(ibuf, err);
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estr = _strerdoc(err);
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if (!estr) estr = "EUNKNOWN";
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Write(thing, ": ", call, "() failed: ", estr, " (", ibuf, ")\n", NULL);
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exit(rc);
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wontreturn void SysExit(const char *func) {
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const char *errstr;
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if (!(errstr = _strerdoc(errno))) errstr = "EUNKNOWN";
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Print(2, epath, ": ", func, " failed with ", errstr, "\n", NULL);
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exit(1);
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}
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static void GetOpts(int argc, char *argv[]) {
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void GetOpts(int argc, char *argv[]) {
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int opt;
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mode = O_RDWR;
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while ((opt = getopt(argc, argv, GETOPTS)) != -1) {
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switch (opt) {
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case 'c':
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mode = O_RDONLY;
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break;
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case 'h':
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case '?':
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write(1, USAGE, sizeof(USAGE) - 1);
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@ -101,17 +117,56 @@ static void GetOpts(int argc, char *argv[]) {
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}
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}
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Elf64_Shdr *FindElfSectionByName(const char *name) {
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long i;
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Elf64_Shdr *shdr;
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for (i = 0; i < elf->e_shnum; ++i) {
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shdr = GetElfSectionHeaderAddress(elf, esize, i);
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if (!strcmp(GetElfString(elf, esize, secstrs, shdr->sh_name), name)) {
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return shdr;
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}
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}
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return 0;
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}
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void CheckPrivilegedCrossReferences(void) {
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long i, x;
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Elf64_Shdr *shdr;
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const char *secname;
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Elf64_Rela *rela, *erela;
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if (!(shdr = FindElfSectionByName(".rela.privileged"))) return;
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rela = GetElfSectionAddress(elf, esize, shdr);
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erela = rela + shdr->sh_size / sizeof(*rela);
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for (; rela < erela; ++rela) {
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if (!ELF64_R_TYPE(rela->r_info)) continue;
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if (!(x = ELF64_R_SYM(rela->r_info))) continue;
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if (syms[x].st_shndx == SHN_ABS) continue;
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if (!syms[x].st_shndx) continue;
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shdr = GetElfSectionHeaderAddress(elf, esize, syms[x].st_shndx);
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if (~shdr->sh_flags & SHF_EXECINSTR) continue; // data reference
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secname = GetElfString(elf, esize, secstrs, shdr->sh_name);
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if (strcmp(".privileged", secname)) {
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Print(2, epath,
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": code in .privileged section "
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"references symbol '",
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GetElfString(elf, esize, symstrs, syms[x].st_name),
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"' in unprivileged code section '", secname, "'\n", NULL);
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exit(1);
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}
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}
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}
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// Modify ARM64 code to use x28 for TLS rather than tpidr_el0.
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void RewriteTlsCode(Elf64_Ehdr *elf, size_t elfsize) {
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void RewriteTlsCode(void) {
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int i, dest;
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Elf64_Shdr *shdr;
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uint32_t *p, *pe;
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for (i = 0; i < elf->e_shnum; ++i) {
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shdr = GetElfSectionHeaderAddress(elf, elfsize, i);
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shdr = GetElfSectionHeaderAddress(elf, esize, i);
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if (shdr->sh_type == SHT_PROGBITS && //
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(shdr->sh_flags & SHF_ALLOC) && //
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(shdr->sh_flags & SHF_EXECINSTR) && //
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(p = GetElfSectionAddress(elf, elfsize, shdr))) {
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(p = GetElfSectionAddress(elf, esize, shdr))) {
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for (pe = p + shdr->sh_size / 4; p <= pe; ++p) {
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if ((*p & -32) == MRS_TPIDR_EL0) {
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*p = MOV_REG(*p & 31, COSMO_TLS_REG);
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@ -131,19 +186,16 @@ void RewriteTlsCode(Elf64_Ehdr *elf, size_t elfsize) {
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* In order for this to work, the function symbol must be declared as
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* `STT_FUNC` and `st_size` must have the function's byte length.
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*/
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void OptimizePatchableFunctionEntries(Elf64_Ehdr *elf, size_t elfsize) {
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void OptimizePatchableFunctionEntries(void) {
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#ifdef __x86_64__
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long i, n;
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int nopcount;
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Elf64_Sym *syms;
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Elf64_Shdr *shdr;
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Elf64_Xword symcount;
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unsigned char *p, *pe;
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CHECK_NOTNULL((syms = GetElfSymbolTable(elf, elfsize, &symcount)));
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for (i = 0; i < symcount; ++i) {
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if (ELF64_ST_TYPE(syms[i].st_info) == STT_FUNC && syms[i].st_size) {
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shdr = GetElfSectionHeaderAddress(elf, elfsize, syms[i].st_shndx);
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p = GetElfSectionAddress(elf, elfsize, shdr);
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shdr = GetElfSectionHeaderAddress(elf, esize, syms[i].st_shndx);
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p = GetElfSectionAddress(elf, esize, shdr);
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p += syms[i].st_value;
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pe = p + syms[i].st_size;
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for (; p + 1 < pe; p += n) {
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@ -159,27 +211,22 @@ void OptimizePatchableFunctionEntries(Elf64_Ehdr *elf, size_t elfsize) {
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#endif /* __x86_64__ */
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}
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void OptimizeRelocations(Elf64_Ehdr *elf, size_t elfsize) {
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char *strs;
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void OptimizeRelocations(void) {
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Elf64_Half i;
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Elf64_Sym *syms;
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Elf64_Rela *rela;
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Elf64_Xword symcount;
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unsigned char *code, *p;
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Elf64_Shdr *shdr, *shdrcode;
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CHECK_NOTNULL((strs = GetElfStringTable(elf, elfsize)));
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CHECK_NOTNULL((syms = GetElfSymbolTable(elf, elfsize, &symcount)));
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for (i = 0; i < elf->e_shnum; ++i) {
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shdr = GetElfSectionHeaderAddress(elf, elfsize, i);
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shdr = GetElfSectionHeaderAddress(elf, esize, i);
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if (shdr->sh_type == SHT_RELA) {
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CHECK_EQ(sizeof(struct Elf64_Rela), shdr->sh_entsize);
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CHECK_NOTNULL(
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(shdrcode = GetElfSectionHeaderAddress(elf, elfsize, shdr->sh_info)));
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(shdrcode = GetElfSectionHeaderAddress(elf, esize, shdr->sh_info)));
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if (!(shdrcode->sh_flags & SHF_EXECINSTR)) continue;
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CHECK_NOTNULL((code = GetElfSectionAddress(elf, elfsize, shdrcode)));
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for (rela = GetElfSectionAddress(elf, elfsize, shdr);
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CHECK_NOTNULL((code = GetElfSectionAddress(elf, esize, shdrcode)));
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for (rela = GetElfSectionAddress(elf, esize, shdr);
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((uintptr_t)rela + shdr->sh_entsize <=
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MIN((uintptr_t)elf + elfsize,
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MIN((uintptr_t)elf + esize,
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(uintptr_t)elf + shdr->sh_offset + shdr->sh_size));
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++rela) {
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@ -189,7 +236,7 @@ void OptimizeRelocations(Elf64_Ehdr *elf, size_t elfsize) {
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* Then libc/runtime/ftrace.greg.c morphs it back at runtime.
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*/
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if (ELF64_R_TYPE(rela->r_info) == R_X86_64_GOTPCRELX &&
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strcmp(GetElfString(elf, elfsize, strs,
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strcmp(GetElfString(elf, esize, symstrs,
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syms[ELF64_R_SYM(rela->r_info)].st_name),
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"mcount") == 0) {
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rela->r_info = R_X86_64_NONE;
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@ -207,7 +254,7 @@ void OptimizeRelocations(Elf64_Ehdr *elf, size_t elfsize) {
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*/
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if ((ELF64_R_TYPE(rela->r_info) == R_X86_64_PC32 ||
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ELF64_R_TYPE(rela->r_info) == R_X86_64_PLT32) &&
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strcmp(GetElfString(elf, elfsize, strs,
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strcmp(GetElfString(elf, esize, symstrs,
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syms[ELF64_R_SYM(rela->r_info)].st_name),
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"mcount") == 0) {
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rela->r_info = R_X86_64_NONE;
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@ -223,45 +270,65 @@ void OptimizeRelocations(Elf64_Ehdr *elf, size_t elfsize) {
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}
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}
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void RewriteObject(const char *path) {
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void FixupObject(void) {
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int fd;
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struct stat st;
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Elf64_Ehdr *elf;
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if ((fd = open(path, O_RDWR)) == -1) {
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SysExit(__COUNTER__ + 1, "open", path);
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if ((fd = open(epath, mode)) == -1) {
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SysExit("open");
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}
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if (fstat(fd, &st) == -1) {
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SysExit(__COUNTER__ + 1, "fstat", path);
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if ((esize = lseek(fd, 0, SEEK_END)) == -1) {
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SysExit("lseek");
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}
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if (st.st_size >= 64) {
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if ((elf = mmap(0, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
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0)) == MAP_FAILED) {
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SysExit(__COUNTER__ + 1, "mmap", path);
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if (esize) {
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if ((elf = mmap(0, esize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) ==
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MAP_FAILED) {
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SysExit("mmap");
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}
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if (elf->e_machine == EM_NEXGEN32E) {
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OptimizeRelocations(elf, st.st_size);
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OptimizePatchableFunctionEntries(elf, st.st_size);
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if (!IsElf64Binary(elf, esize)) {
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Print(2, epath, ": not an elf64 binary\n", NULL);
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exit(1);
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}
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if (elf->e_machine == EM_AARCH64) {
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RewriteTlsCode(elf, st.st_size);
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if (!(syms = GetElfSymbolTable(elf, esize, &symcount))) {
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Print(2, epath, ": missing elf symbol table\n", NULL);
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exit(1);
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}
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if (msync(elf, st.st_size, MS_ASYNC | MS_INVALIDATE)) {
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SysExit(__COUNTER__ + 1, "msync", path);
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if (!(secstrs = GetElfSectionNameStringTable(elf, esize))) {
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Print(2, epath, ": missing elf section string table\n", NULL);
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exit(1);
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}
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if (munmap(elf, st.st_size)) {
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SysExit(__COUNTER__ + 1, "munmap", path);
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if (!(symstrs = GetElfStringTable(elf, esize))) {
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Print(2, epath, ": missing elf symbol string table\n", NULL);
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exit(1);
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}
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CheckPrivilegedCrossReferences();
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if (mode == O_RDWR) {
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if (elf->e_machine == EM_NEXGEN32E) {
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OptimizeRelocations();
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OptimizePatchableFunctionEntries();
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}
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if (elf->e_machine == EM_AARCH64) {
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RewriteTlsCode();
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}
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if (msync(elf, esize, MS_ASYNC | MS_INVALIDATE)) {
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SysExit("msync");
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}
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}
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if (munmap(elf, esize)) {
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SysExit("munmap");
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}
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}
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if (close(fd)) {
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SysExit(__COUNTER__ + 1, "close", path);
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SysExit("close");
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}
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}
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int main(int argc, char *argv[]) {
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int i, opt;
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if (IsModeDbg()) ShowCrashReports();
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if (!IsOptimized()) {
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ShowCrashReports();
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}
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GetOpts(argc, argv);
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for (i = optind; i < argc; ++i) {
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RewriteObject(argv[i]);
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epath = argv[i];
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FixupObject();
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}
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}
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