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tccrun: 'selinux' mmap: use only one mapping 

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.
master
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
}