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switched from multiple mmap to one

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This commit is contained in:
Cristian Toader 2013-08-29 16:51:05 +03:00
parent f93ba9a2ef
commit 1118bd9910
1 changed files with 58 additions and 29 deletions
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87
src/common/sandbox.c
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@ -678,36 +678,65 @@ sandbox_intern_string(const char *param)
return param;
}
static char*
prot_strdup(char* str)
{
int param_size = 0;
char *res = NULL;
static int
prot_strings(sandbox_cfg_t* cfg) {
int ret = 0;
int pr_mem_size = 0, pr_mem_left = 0;
char *pr_mem_next = NULL, *pr_mem_base;
sandbox_cfg_t *el = NULL;
if (str == NULL)
goto out;
// get total number of bytes required to mmap
for(el = cfg; el != NULL; el = el->next) {
pr_mem_size += strlen((char*) el->param) + 1;
}
// allocating protected memory region for parameter
param_size = 1 + strlen(str);
res = (char*) mmap(NULL, param_size, PROT_READ | PROT_WRITE, MAP_PRIVATE |
MAP_ANON, -1, 0);
if (!res) {
log_err(LD_BUG,"(Sandbox) failed allocate protected memory!");
// allocate protected memory
pr_mem_base = (char*) mmap(NULL, pr_mem_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON, -1, 0);
if (pr_mem_base == MAP_FAILED) {
log_err(LD_BUG,"(Sandbox) failed allocate protected memory! mmap: %s",
strerror(errno));
ret = -1;
goto out;
}
// copying from non protected to protected + pointer reassign
memcpy(res, str, param_size);
pr_mem_next = pr_mem_base;
pr_mem_left = pr_mem_size;
// change el value pointer to protected
for (el = cfg; el != NULL; el = el->next) {
char *param_val = (char*) el->param;
int param_size = strlen(param_val) + 1;
if (pr_mem_left - param_size >= 0) {
// copy to protected
memcpy(pr_mem_next, param_val, param_size);
// re-point el parameter to protected
free((char*) el->param);
el->param = (intptr_t) pr_mem_next;
el->prot = 1;
// move next available protected memory
pr_mem_next += param_size;
pr_mem_left -= param_size;
} else {
log_err(LD_BUG,"(Sandbox) insufficient protected memory!");
ret = -2;
goto out;
}
}
// protecting from writes
if (mprotect(res, param_size, PROT_READ)) {
log_err(LD_BUG,"(Sandbox) failed to protect memory!");
return NULL;
if (mprotect(pr_mem_base, pr_mem_size, PROT_READ)) {
log_err(LD_BUG,"(Sandbox) failed to protect memory! mprotect: %s",
strerror(errno));
ret = -3;
goto out;
}
out:
return res;
return ret;
}
#ifdef __NR_stat64
@ -719,8 +748,8 @@ sandbox_cfg_allow_stat64_filename(sandbox_cfg_t **cfg, char *file, int fr)
elem = (sandbox_cfg_t*) malloc(sizeof(sandbox_cfg_t));
elem->syscall = SCMP_SYS(stat64);
elem->pindex = 0;
elem->param = (intptr_t) prot_strdup((char*) file);
elem->prot = 1;
elem->param = (intptr_t) strdup(file);
elem->prot = 0;
elem->next = *cfg;
*cfg = elem;
@ -763,8 +792,8 @@ sandbox_cfg_allow_open_filename(sandbox_cfg_t **cfg, char *file, int fr)
elem = (sandbox_cfg_t*) malloc(sizeof(sandbox_cfg_t));
elem->syscall = SCMP_SYS(open);
elem->pindex = 0;
elem->param = (intptr_t) prot_strdup((char*) file);
elem->prot = 1;
elem->param = (intptr_t) strdup(file);
elem->prot = 0;
elem->next = *cfg;
*cfg = elem;
@ -806,8 +835,8 @@ sandbox_cfg_allow_openat_filename(sandbox_cfg_t **cfg, char *file, int fr)
elem = (sandbox_cfg_t*) malloc(sizeof(sandbox_cfg_t));
elem->syscall = SCMP_SYS(openat);
elem->pindex = 1;
elem->param = (intptr_t) prot_strdup((char*) file);;
elem->prot = 1;
elem->param = (intptr_t) strdup(file);
elem->prot = 0;
elem->next = *cfg;
*cfg = elem;
@ -849,8 +878,8 @@ sandbox_cfg_allow_execve(sandbox_cfg_t **cfg, char *com)
elem = (sandbox_cfg_t*) malloc(sizeof(sandbox_cfg_t));
elem->syscall = SCMP_SYS(openat);
elem->pindex = 1;
elem->param = (intptr_t) prot_strdup((char*) com);;
elem->prot = 1;
elem->param = (intptr_t) strdup(com);
elem->prot = 0;
elem->next = *cfg;
*cfg = elem;
@ -1121,7 +1150,7 @@ initialise_libseccomp_sandbox(sandbox_cfg_t* cfg)
if (install_sigsys_debugging())
return -1;
if (init_addrinfo()) {
if (init_addrinfo() || prot_strings(cfg)) {
return -4;
}