malloc.c
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/*
clsync - file tree sync utility based on inotify
Copyright (C) 2013 Dmitry Yu Okunev <dyokunev@ut.mephi.ru> 0x8E30679C
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "macros.h"
#include <stdlib.h>
#include <string.h>
#ifdef CAPABILITIES_SUPPORT
# include <unistd.h>
# include <sys/mman.h>
# ifdef SECCOMP_SUPPORT
# include <sys/stat.h>
# include <fcntl.h>
# endif
#endif
#include <sys/ipc.h> // shmget()
#include <sys/shm.h> // shmget()
#include "malloc.h"
#include "error.h"
#include "configuration.h"
#ifdef CAPABILITIES_SUPPORT
long pagesize;
# ifdef SECCOMP_SUPPORT
int devzero_fd;
# endif
#endif
void *xmalloc(size_t size) {
debug(20, "(%li)", size);
#ifdef PARANOID
size++; // Just in case
#endif
void *ret = malloc(size);
if (ret == NULL)
critical("(%li): Cannot allocate memory.", size);
#ifdef PARANOID
memset(ret, 0, size);
#endif
return ret;
}
void *xcalloc(size_t nmemb, size_t size) {
debug(20, "(%li, %li)", nmemb, size);
#ifdef PARANOID
nmemb++; // Just in case
size++; // Just in case
#endif
void *ret = calloc(nmemb, size);
if (ret == NULL)
critical("(%li): Cannot allocate memory.", size);
// memset(ret, 0, nmemb*size); // Just in case
return ret;
}
void *xrealloc(void *oldptr, size_t size) {
debug(20, "(%p, %li)", oldptr, size);
#ifdef PARANOID
size++; // Just in case
#endif
void *ret = realloc(oldptr, size);
if (ret == NULL)
critical("(%p, %li): Cannot reallocate memory.", oldptr, size);
return ret;
}
#ifdef CAPABILITIES_SUPPORT
void *malloc_align(size_t size) {
size_t total_size;
void *ret = NULL;
debug(20, "(%li)", size);
# ifdef PARANOID
size++; // Just in case
# endif
total_size = size;
// Rounding total_size up to a number of times pagesize
total_size += pagesize-1;
total_size /= pagesize;
total_size *= pagesize;
if (posix_memalign(&ret, pagesize, total_size))
critical("(%li): Cannot allocate memory.", size);
# ifdef PARANOID
if (ret == NULL)
critical("(%li): ptr == NULL.", size);
# endif
// memset(ret, 0, nmemb*size); // Just in case
return ret;
}
void *calloc_align(size_t nmemb, size_t size) {
size_t total_size;
void *ret;
debug(20, "(%li, %li)", nmemb, size);
# ifdef PARANOID
nmemb++; // Just in case
size++; // Just in case
# endif
total_size = nmemb*size;
ret = malloc_align(total_size);
memset(ret, 0, total_size);
return ret;
}
char *strdup_protect(const char *src, int prot) {
size_t len = strlen(src)+1;
char *dst = malloc_align(len);
strcpy(dst, src);
if (mprotect(dst, len, prot))
critical("(%p, 0x%o): Got error from mprotect(%p, %lu, 0x%o)", src, prot, dst, len, prot);
return dst;
}
# ifdef SECCOMP_SUPPORT
int is_protected(void *addr) {
char *_addr = addr, t;
int is_protected;
t = *_addr;
is_protected = (read(devzero_fd, addr, 1) == -1);
if (!is_protected)
*_addr = t;
return is_protected;
}
# endif
#endif
int memory_init() {
#ifdef CAPABILITIES_SUPPORT
pagesize = sysconf(_SC_PAGE_SIZE);
if (pagesize == -1)
critical("Got error from sysconf(_SC_PAGE_SIZE)");
# ifdef SECCOMP_SUPPORT
devzero_fd = open(DEVZERO, O_RDONLY);
if (devzero_fd == -1)
critical("Got error while open(\""DEVZERO"\", O_RDONLY)");
# endif
#endif
return 0;
}
void *shm_malloc_try(size_t size) {
void *ret;
#ifdef PARANOID
size++;
#endif
int privileged_shmid = shmget(0, size, IPC_PRIVATE|IPC_CREAT|0600);
struct shmid_ds shmid_ds;
if (privileged_shmid == -1) return NULL;
ret = shmat(privileged_shmid, NULL, 0);
if ((long)ret == -1) return NULL;
debug(15, "ret == %p", ret);
// Forbidding access for others to the pointer
shmctl(privileged_shmid, IPC_STAT, &shmid_ds);
shmid_ds.shm_perm.mode = 0;
shmctl(privileged_shmid, IPC_SET, &shmid_ds);
// Checking that nobody else attached to the shared memory before access forbidding
shmctl(privileged_shmid, IPC_STAT, &shmid_ds);
if (shmid_ds.shm_lpid != shmid_ds.shm_cpid) {
error("A process (pid %u) attached to my shared memory. It's a security problem. Emergency exit.");
shmdt (ret);
return NULL;
}
return ret;
}
void *shm_malloc(size_t size) {
void *ret;
ret = shm_malloc_try(size);
critical_on (ret == NULL);
return ret;
}
void *shm_calloc(size_t nmemb, size_t size) {
void *ret;
size_t total_size;
#ifdef PARANOID
nmemb++;
size++;
#endif
total_size = nmemb * size;
ret = shm_malloc(total_size);
critical_on (ret == NULL);
memset(ret, 0, total_size);
return ret;
}
void shm_free(void *ptr) {
debug(25, "(%p)", ptr);
shmdt(ptr);
}