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tccrun: 'selinux' mmap: use only one mapping

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In the previous implementation, the rx mapping was never
used.  Therefor it is assumed that it is not needed.

With only one mapping there is no reason to use a real
/tmp/.xxxx file either as we can use an anonymous mapping.
This commit is contained in:
grischka 2017-02-05 13:58:14 +01:00
parent 5420bb8a67
commit ea2c36c5a9
1 changed files with 19 additions and 38 deletions
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57
tccrun.c
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@ -60,7 +60,7 @@ static void win64_del_function_table(void *);
LIBTCCAPI int tcc_relocate(TCCState *s1, void *ptr)
{
int size; void *mem;
int size;
if (TCC_RELOCATE_AUTO != ptr)
return tcc_relocate_ex(s1, ptr);
@ -70,35 +70,17 @@ LIBTCCAPI int tcc_relocate(TCCState *s1, void *ptr)
return -1;
#ifdef HAVE_SELINUX
{ /* Use mmap instead of malloc for Selinux. Ref:
http://www.gnu.org/s/libc/manual/html_node/File-Size.html */
char tmpfname[] = "/tmp/.tccrunXXXXXX";
int fd = mkstemp (tmpfname);
void *wr_mem;
unlink (tmpfname);
ftruncate (fd, size);
wr_mem = mmap (NULL, size, PROT_READ|PROT_WRITE,
MAP_SHARED, fd, 0);
if (wr_mem == MAP_FAILED)
tcc_error("/tmp not writeable");
mem = mmap (NULL, size, PROT_READ|PROT_EXEC,
MAP_SHARED, fd, 0);
if (mem == MAP_FAILED)
tcc_error("/tmp not executable");
tcc_relocate_ex(s1, wr_mem);
dynarray_add(&s1->runtime_mem, &s1->nb_runtime_mem, (void*)(addr_t)size);
dynarray_add(&s1->runtime_mem, &s1->nb_runtime_mem, wr_mem);
dynarray_add(&s1->runtime_mem, &s1->nb_runtime_mem, mem);
}
/* Use mmap instead of malloc for Selinux. */
ptr = mmap (NULL, size, PROT_READ|PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (ptr == MAP_FAILED)
tcc_error("tccrun: could not map memory");
dynarray_add(&s1->runtime_mem, &s1->nb_runtime_mem, (void*)(addr_t)size);
#else
mem = tcc_malloc(size);
tcc_relocate_ex(s1, mem); /* no more errors expected */
dynarray_add(&s1->runtime_mem, &s1->nb_runtime_mem, mem);
ptr = tcc_malloc(size);
#endif
tcc_relocate_ex(s1, ptr); /* no more errors expected */
dynarray_add(&s1->runtime_mem, &s1->nb_runtime_mem, ptr);
return 0;
}
@ -108,13 +90,12 @@ ST_FUNC void tcc_run_free(TCCState *s1)
for (i = 0; i < s1->nb_runtime_mem; ++i) {
#ifdef HAVE_SELINUX
int size = (int)(addr_t)s1->runtime_mem[i];
munmap(s1->runtime_mem[++i], size);
munmap(s1->runtime_mem[++i], size);
unsigned size = (unsigned)(addr_t)s1->runtime_mem[i++];
munmap(s1->runtime_mem[i], size);
#else
# ifdef _WIN64
#ifdef _WIN64
win64_del_function_table(*(void**)s1->runtime_mem[i]);
# endif
#endif
tcc_free(s1->runtime_mem[i]);
#endif
}
@ -264,19 +245,19 @@ static void set_pages_executable(void *ptr, unsigned long length)
unsigned long old_protect;
VirtualProtect(ptr, length, PAGE_EXECUTE_READWRITE, &old_protect);
#else
void __clear_cache(void *beginning, void *end);
addr_t start, end;
#ifndef PAGESIZE
# define PAGESIZE 4096
#endif
addr_t start, end;
start = (addr_t)ptr & ~(PAGESIZE - 1);
end = (addr_t)ptr + length;
end = (end + PAGESIZE - 1) & ~(PAGESIZE - 1);
if (mprotect((void *)start, end - start, PROT_READ | PROT_WRITE | PROT_EXEC))
tcc_error("mprotect failed: did you mean to configure --with-selinux?");
#if defined TCC_TARGET_ARM || defined TCC_TARGET_ARM64
{ extern void __clear_cache(void *beginning, void *end);
__clear_cache(ptr, (char *)ptr + length); }
#endif
# if defined TCC_TARGET_ARM || defined TCC_TARGET_ARM64
__clear_cache(ptr, (char *)ptr + length);
# endif
#endif
}