mirror of
https://github.com/jart/cosmopolitan.git
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133c693650
This change fixes Landlock Make so that only the output target file is unveiled, rather than unveiling the directory that contains it. This gives us a much stronger sandbox. It also helped identify problematic build code in our repo that should have been using o/tmp instead. Landlock isn't able to let us unveil files that don't exist. Even if they do, then once a file is deleted, the sandboxing for it goes away. This caused problems for Landlock Make because tools like GNU LD will repeatedly delete and recreate the output file. This change uses the compile.com wrapper to ensure on changes happen to the output inode. New binary available on https://justine.lol/make/ Fixes #528
120 lines
5.5 KiB
C
120 lines
5.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 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/calls/struct/iovec.h"
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#include "libc/log/check.h"
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#include "libc/macros.internal.h"
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#include "libc/nexgen32e/bsr.h"
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#include "libc/runtime/gc.internal.h"
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#include "libc/sock/sock.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/x/x.h"
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#include "tool/build/lib/persist.h"
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static bool IsWithin(size_t sz1, void *vp1, size_t sz2, void *vp2) {
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char *p1 = vp1, *p2 = vp2;
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return p1 >= p2 && p1 + sz1 <= p2 + sz2;
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}
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static bool IsOverlapping(void *vx1, void *vy1, void *vx2, void *vy2) {
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char *x1 = vx1, *y1 = vy1, *x2 = vx2, *y2 = vy2;
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return (x1 >= x2 && x1 <= y2) || (y1 >= x2 && y1 <= y2);
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}
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static bool IsOverlappingIov(struct iovec *a, struct iovec *b) {
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char *ap = a->iov_base, *bp = b->iov_base;
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return IsOverlapping(ap, ap + a->iov_len, bp, bp + b->iov_len);
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}
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/**
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* Writes struct w/ dynamic arrays to mappable file, e.g.
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*
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* PersistObject(path, 64, &(struct ObjectParam){
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* sizeof(*o), o, &o->magic, &o->abi,
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* &(struct ObjectArrayParam){
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* {&o->a1.i, sizeof(o->a1.p[0]), &o->a1.p},
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* {&o->a2.i, sizeof(o->a2.p[0]), &o->a2.p},
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* {0},
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* }});
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*
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* @param obj->magic needs to be unique for struct
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* @param obj->abi monotonically tracks breaking changes
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* @param obj->arrays needs sentinel with item size of zero
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* @note non-recursive i.e. array elements can't have pointers
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* @see MapObject()
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*/
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void PersistObject(const char *path, size_t align,
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const struct ObjectParam *obj) {
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const char *pad;
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struct iovec *iov;
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int i, n, fd, iovlen;
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long len, size, bytes, filesize;
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unsigned char *hdr, *p1, *p2, **pp;
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intptr_t arrayptroffset, arraydataoffset;
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filesize = 0;
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DCHECK_GE(align, 1);
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CHECK_GT(*obj->magic, 0);
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CHECK_GT(*obj->abi, 0);
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CHECK(IsWithin(sizeof(*obj->magic), obj->magic, obj->size, obj->p));
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CHECK(IsWithin(sizeof(*obj->abi), obj->abi, obj->size, obj->p));
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for (n = i = 0; obj->arrays[i].size; ++i) ++n;
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iovlen = (n + 1) * 2;
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pad = gc(xcalloc(align, 1));
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hdr = gc(xmalloc(obj->size));
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iov = gc(xcalloc(iovlen, sizeof(*iov)));
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bytes = obj->size;
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iov[0].iov_base = memcpy(hdr, obj->p, obj->size);
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iov[0].iov_len = bytes;
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iov[1].iov_base = pad;
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iov[1].iov_len = ROUNDUP(bytes, align) - bytes;
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filesize += ROUNDUP(bytes, align);
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for (i = 0; i < n; ++i) {
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pp = obj->arrays[i].pp;
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len = obj->arrays[i].len;
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size = obj->arrays[i].size;
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if (!*pp || !len) continue;
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p1 = obj->p;
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p2 = obj->arrays[i].pp;
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arrayptroffset = p2 - p1;
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arraydataoffset = filesize;
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CHECK((!len || bsrl(len) + bsrl(size) < 31),
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"path=%s i=%d len=%,lu size=%,lu", path, i, len, size);
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CHECK(IsWithin(sizeof(void *), pp, obj->size, obj->p));
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CHECK(!IsOverlapping(pp, pp + sizeof(void *), obj->magic,
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obj->magic + sizeof(*obj->magic)));
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CHECK(!IsOverlapping(pp, pp + sizeof(void *), obj->abi,
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obj->abi + sizeof(*obj->abi)));
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memcpy(hdr + arrayptroffset, &arraydataoffset, sizeof(intptr_t));
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CHECK_LT(filesize + arraydataoffset, 0x7ffff000);
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bytes = len * size;
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iov[(i + 1) * 2 + 0].iov_base = *pp;
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iov[(i + 1) * 2 + 0].iov_len = bytes;
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iov[(i + 1) * 2 + 1].iov_base = pad;
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iov[(i + 1) * 2 + 1].iov_len = ROUNDUP(bytes, align) - bytes;
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filesize += ROUNDUP(bytes, align);
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CHECK(!IsOverlappingIov(&iov[(i + 0) * 2], &iov[(i + 1) * 2]),
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"iov[%d]={%#p,%#x}, iov[%d]={%#p,%#x} path=%s", (i + 0) * 2,
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iov[(i + 0) * 2].iov_base, iov[(i + 0) * 2].iov_len, (i + 1) * 2,
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iov[(i + 1) * 2].iov_base, iov[(i + 1) * 2].iov_len, path);
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}
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CHECK_NE(-1, (fd = creat(path, 0644)), "%s", path);
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CHECK_EQ(filesize, writev(fd, iov, iovlen));
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CHECK_NE(-1, close(fd));
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}
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