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syscalls: Sanitize all pointers #606

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syscalls: Sanitize all pointers #606

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134 changes: 113 additions & 21 deletions syscalls.c
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Original file line number Diff line number Diff line change
Expand Up @@ -36,12 +36,14 @@

void syscalls_debug(void *ustack)
{
process_t *proc = proc_current()->process;
const char *s;

/* FIXME: pass strlen(s) from userspace */

GETFROMSTACK(ustack, const char *, s, 0);
hal_consolePrint(ATTR_USER, s);

if (vm_mapStringBelongs(proc, s) == 0) {
hal_consolePrint(ATTR_USER, s);
}
}


Expand Down Expand Up @@ -173,52 +175,119 @@ int syscalls_release(void *ustack)
}


static int syscalls_sanitizeVector(process_t *proc, char **v)
{
size_t i;

if (v == NULL) {
return 0;
}

if (vm_mapBelongs(proc, v, sizeof(v)) < 0) {
return -1;
}

for (i = 0;; ++i) {
if (vm_mapBelongs(proc, &v[i], sizeof(v)) < 0) {
return -1;
}

if (v[i] == NULL) {
break;
}

if (vm_mapStringBelongs(proc, v[i]) < 0) {
return -1;
}
}

return 0;
}


int syscalls_sys_spawn(void *ustack)
{
process_t *proc = proc_current()->process;
char *path;
char **argv;
char **envp;

/* FIXME pass fields lengths from userspace */

GETFROMSTACK(ustack, char *, path, 0);
GETFROMSTACK(ustack, char **, argv, 1);
GETFROMSTACK(ustack, char **, envp, 2);

if (vm_mapStringBelongs(proc, path) < 0) {
return -EFAULT;
}

if (syscalls_sanitizeVector(proc, argv) < 0) {
return -EFAULT;
}

if (syscalls_sanitizeVector(proc, envp) < 0) {
return -EFAULT;
}

return proc_fileSpawn(path, argv, envp);
}


int syscalls_exec(void *ustack)
{
process_t *proc = proc_current()->process;
char *path;
char **argv;
char **envp;

/* FIXME pass fields lengths from userspace */

GETFROMSTACK(ustack, char *, path, 0);
GETFROMSTACK(ustack, char **, argv, 1);
GETFROMSTACK(ustack, char **, envp, 2);

if (vm_mapStringBelongs(proc, path) < 0) {
return -EFAULT;
}

if (syscalls_sanitizeVector(proc, argv) < 0) {
return -EFAULT;
}

if (syscalls_sanitizeVector(proc, envp) < 0) {
return -EFAULT;
}

return proc_execve(path, argv, envp);
}


int syscalls_spawnSyspage(void *ustack)
{
process_t *proc = proc_current()->process;
char *imap;
char *dmap;
char *name;
char **argv;

/* FIXME pass fields lengths from userspace */

GETFROMSTACK(ustack, char *, imap, 0);
GETFROMSTACK(ustack, char *, dmap, 1);
GETFROMSTACK(ustack, char *, name, 2);
GETFROMSTACK(ustack, char **, argv, 3);

if (vm_mapStringBelongs(proc, imap) < 0) {
return -EFAULT;
}

if (vm_mapStringBelongs(proc, dmap) < 0) {
return -EFAULT;
}

if (vm_mapStringBelongs(proc, name) < 0) {
return -EFAULT;
}

if (syscalls_sanitizeVector(proc, argv) < 0) {
return -EFAULT;
}

return proc_syspageSpawnName(imap, dmap, name, argv);
}

Expand Down Expand Up @@ -729,7 +798,9 @@ u32 syscalls_portRegister(void *ustack)
GETFROMSTACK(ustack, char *, name, 1);
GETFROMSTACK(ustack, oid_t *, oid, 2);

/* FIXME: Pass strlen(name) from userspace */
if (vm_mapStringBelongs(proc, name) < 0) {
return -EFAULT;
}

if (vm_mapBelongs(proc, oid, sizeof(*oid)) < 0) {
return -EFAULT;
Expand Down Expand Up @@ -828,7 +899,9 @@ int syscalls_lookup(void *ustack)
GETFROMSTACK(ustack, oid_t *, file, 1);
GETFROMSTACK(ustack, oid_t *, dev, 2);

/* FIXME: Pass strlen(name) from userspace */
if (vm_mapStringBelongs(proc, name) < 0) {
return -EFAULT;
}

if ((file != NULL) && (vm_mapBelongs(proc, file, sizeof(*file)) < 0)) {
return -EFAULT;
Expand Down Expand Up @@ -1066,14 +1139,17 @@ void syscalls_sigreturn(void *ustack)

int syscalls_sys_open(char *ustack)
{
process_t *proc = proc_current()->process;
const char *filename;
int oflag;

/* FIXME: pass strlen(filename) from userspace */

GETFROMSTACK(ustack, const char *, filename, 0);
GETFROMSTACK(ustack, int, oflag, 1);

if (vm_mapStringBelongs(proc, filename) < 0) {
return -EFAULT;
}

return posix_open(filename, oflag, ustack);
}

Expand Down Expand Up @@ -1158,26 +1234,36 @@ int syscalls_sys_dup2(char *ustack)

int syscalls_sys_link(char *ustack)
{
process_t *proc = proc_current()->process;
const char *path1;
const char *path2;

/* FIXME pass strlen(path1) and strlen(path2) from userspace */

GETFROMSTACK(ustack, const char *, path1, 0);
GETFROMSTACK(ustack, const char *, path2, 1);

if (vm_mapStringBelongs(proc, path1) < 0) {
return -EFAULT;
}

if (vm_mapStringBelongs(proc, path2) < 0) {
return -EFAULT;
}

return posix_link(path1, path2);
}


int syscalls_sys_unlink(char *ustack)
{
process_t *proc = proc_current()->process;
const char *pathname;

/* FIXME: pass strlen(pathname) from userspace */

GETFROMSTACK(ustack, const char *, pathname, 0);

if (vm_mapStringBelongs(proc, pathname) < 0) {
return -EFAULT;
}

return posix_unlink(pathname);
}

Expand Down Expand Up @@ -1242,14 +1328,17 @@ int syscalls_sys_pipe(char *ustack)

int syscalls_sys_mkfifo(char *ustack)
{
process_t *proc = proc_current()->process;
const char *path;
mode_t mode;

/* FIXME: pass strlen(path) from userspace */

GETFROMSTACK(ustack, const char *, path, 0);
GETFROMSTACK(ustack, mode_t, mode, 1);

if (vm_mapStringBelongs(proc, path) < 0) {
return -EFAULT;
}

return posix_mkfifo(path, mode);
}

Expand Down Expand Up @@ -1283,14 +1372,17 @@ int syscalls_sys_fsync(char *ustack)

int syscalls_sys_chmod(char *ustack)
{
process_t *proc = proc_current()->process;
const char *path;
mode_t mode;

/* FIXME: pass strlen(path) from userspace */

GETFROMSTACK(ustack, const char *, path, 0);
GETFROMSTACK(ustack, mode_t, mode, 1);

if (vm_mapStringBelongs(proc, path) < 0) {
return -EFAULT;
}

return posix_chmod(path, mode);
}

Expand Down
27 changes: 27 additions & 0 deletions vm/map.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1120,6 +1120,33 @@
}


int vm_mapStringBelongs(const struct _process_t *proc, const char *str)
{
int ret;

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const char *page = (const char *)((ptr_t)str & (SIZE_PAGE - 1));
size_t offs = (ptr_t)str - (ptr_t)page;

proc_lockSet(&proc->mapp->lock);

while (_vm_mapBelongs(proc, page, SIZE_PAGE) == 0) {
while (offs < SIZE_PAGE) {
if (page[offs] == '\0') {
proc_lockClear(&proc->mapp->lock);
return 0;
}

++offs;
}

page += SIZE_PAGE;
offs = 0;
}
proc_lockClear(&proc->mapp->lock);

return -1;
}


void vm_mapinfo(meminfo_t *info)
{
rbnode_t *n;
Expand Down
3 changes: 3 additions & 0 deletions vm/map.h
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Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,9 @@ extern vm_map_t *vm_getSharedMap(int map);
extern int vm_mapBelongs(const struct _process_t *proc, const void *ptr, size_t size);


extern int vm_mapStringBelongs(const struct _process_t *proc, const char *str);


extern int _map_init(vm_map_t *kmap, struct _vm_object_t *kernel, void **start, void **end);


Expand Down
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