mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-08-08 10:50:28 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

zipos mmap disallow MAP_SHARED, propgate original errno, add more tests

Browse source
This commit is contained in:
Gavin Hayes 2023-02-01 14:11:52 -05:00
parent 38f876aee7
commit 7f87f0cc59
2 changed files with 97 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

35
libc/zipos/mmap.c
View file

@ -19,6 +19,7 @@
#include "libc/calls/calls.h"
#include "libc/calls/struct/iovec.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/likely.h"
#include "libc/intrin/strace.internal.h"
#include "libc/sysv/consts/map.h"
@ -29,14 +30,32 @@
#define IP(X) (intptr_t)(X)
#define VIP(X) (void *)IP(X)
/**
* Map zipos file into memory. See mmap.
*
* @param addr should be 0 or a compatible address
* @param size must be >0 and will be rounded up to FRAMESIZE
* automatically.
* @param prot can have PROT_READ/PROT_WRITE/PROT_EXEC/PROT_NONE/etc.
* @param flags cannot have `MAP_SHARED` or `MAP_ANONYMOUS`, there is
* no actual file backing for zipos files. `MAP_SHARED` could be
* simulated for non-writable mappings, but that would require
* tracking zipos mappings to prevent making it PROT_WRITE.
* @param h is a zip store object
* @param off specifies absolute byte index of h's file for mapping,
* it does not need to be 64kb aligned.
* @return virtual base address of new mapping, or MAP_FAILED w/ errno
*/
void *__zipos_mmap(void *addr, size_t size, int prot, int flags, struct ZiposHandle *h, int64_t off) {
if (VERY_UNLIKELY(!!(flags & MAP_ANONYMOUS))) {
STRACE("fd anonymous mismatch");
STRACE("MAP_ANONYMOUS zipos mismatch");
return VIP(einval());
}
if (VERY_UNLIKELY(!(!!(prot & PROT_WRITE) ^ !!(flags & MAP_SHARED)))) {
STRACE("PROT_WRITE and MAP_SHARED on zipos");
// MAP_SHARED for non-writeable pages could be implemented, but would require
// keeping track of zipos pages to prevent mprotect(addr,len,PROT_WRITE)
if (VERY_UNLIKELY(!!(flags & MAP_SHARED))) {
STRACE("MAP_SHARED on zipos");
return VIP(eacces());
}
@ -46,13 +65,13 @@ void *__zipos_mmap(void *addr, size_t size, int prot, int flags, struct ZiposHan
return MAP_FAILED;
}
const int64_t beforeOffset = __zipos_lseek(h, 0, SEEK_CUR);
if ((beforeOffset == -1) || (__zipos_read(h, &(struct iovec){outAddr, size}, 1, off) == -1)) {
if ((beforeOffset == -1) || (__zipos_read(h, &(struct iovec){outAddr, size}, 1, off) == -1) ||
(__zipos_lseek(h, beforeOffset, SEEK_SET) == -1) ||
((prot != tempProt) && (mprotect(outAddr, size, prot) == -1))) {
const int e = errno;
munmap(outAddr, size);
errno = e;
return MAP_FAILED;
}
__zipos_lseek(h, beforeOffset, SEEK_SET);
if(prot != tempProt) {
mprotect(outAddr, size, prot);
}
return outAddr;
}

76
test/libc/runtime/mmap_test.c
View file

@ -221,17 +221,81 @@ TEST(isheap, mallocOffset) {
ASSERT_TRUE(_isheap(p + 100000));
}
TEST(mmap, ziposMapFiles) {
static const char *ziposLifePath = "/zip/life.elf";
TEST(mmap, ziposCannotBeAnonymous) {
int fd;
const char *lifepath = "/zip/life.elf";
void *p;
ASSERT_NE(-1, (fd = open(lifepath, O_RDONLY), "%s", lifepath));
ASSERT_NE(NULL, (p = mmap(NULL, 0x00010000, PROT_READ, MAP_SHARED, fd, 0)));
EXPECT_STREQN("ELF", ((const char *)p)+1, 3);
ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
EXPECT_SYS(EINVAL, MAP_FAILED, (p = mmap(NULL, 0x00010000, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, fd, 0)));
close(fd);
}
TEST(mmap, ziposCannotBeShared) {
int fd;
void *p;
ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
EXPECT_SYS(EACCES, MAP_FAILED, (p = mmap(NULL, 0x00010000, PROT_READ, MAP_SHARED, fd, 0)));
close(fd);
}
////////////////////////////////////////////////////////////////////////////////
// zipos NON-SHARED READ-ONLY FILE MEMORY
TEST(mmap, ziposCow) {
int fd;
void *p;
ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
EXPECT_NE(MAP_FAILED, (p = mmap(NULL, 0x00010000, PROT_READ, MAP_PRIVATE, fd, 0)));
EXPECT_STREQN("ELF", ((const char *)p)+1, 3);
EXPECT_NE(-1, munmap(p, 0x00010000));
EXPECT_NE(-1, close(fd));
}
////////////////////////////////////////////////////////////////////////////////
// zipos NON-SHARED READ-ONLY FILE MEMORY BETWEEN PROCESSES
TEST(mmap, ziposCowFileMapReadonlyFork) {
int fd, ws;
void *p;
ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
EXPECT_NE(MAP_FAILED, (p = mmap(NULL, 4, PROT_READ, MAP_PRIVATE, fd, 0)));
EXPECT_STREQN("ELF", ((const char *)p)+1, 3);
ASSERT_NE(-1, (ws = xspawn(0)));
if (ws == -2) {
ASSERT_STREQN("ELF", ((const char *)p)+1, 3);
_exit(0);
}
EXPECT_EQ(0, ws);
EXPECT_STREQN("ELF", ((const char *)p)+1, 3);
EXPECT_NE(-1, munmap(p, 6));
EXPECT_NE(-1, close(fd));
}
////////////////////////////////////////////////////////////////////////////////
// zipos NON-SHARED READ/WRITE FILE MEMORY BETWEEN PROCESSES
TEST(mmap, ziposCowFileMapFork) {
int fd, ws;
void *p;
char lol[4];
ASSERT_NE(-1, (fd = open(ziposLifePath, O_RDONLY), "%s", ziposLifePath));
EXPECT_NE(MAP_FAILED, (p = mmap(NULL, 6, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0)));
memcpy(p, "parnt", 6);
ASSERT_NE(-1, (ws = xspawn(0)));
if (ws == -2) {
ASSERT_STREQN("parnt", p, 5);
strcpy(p, "child");
ASSERT_STREQN("child", p, 5);
_exit(0);
}
EXPECT_EQ(0, ws);
EXPECT_STREQN("parnt", p, 5); // child changing memory did not change parent
EXPECT_EQ(4, pread(fd, lol, 4, 0));
EXPECT_STREQN("ELF", &lol[1], 3); // changing memory did not change file
EXPECT_NE(-1, munmap(p, 6));
EXPECT_NE(-1, close(fd));
}
////////////////////////////////////////////////////////////////////////////////
// NON-SHARED READ-ONLY FILE MEMORY