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extmod/moduhashlib: Put hash obj in final state after digest is called.

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If digest is called then the hash object is put in a "final" state and
calling update() or digest() again will raise a ValueError (instead of
silently producing the wrong result).

See issue #4119.

Signed-off-by: Damien George <damien@micropython.org>
This commit is contained in:
Damien George 2021-05-25 16:48:29 +10:00
parent 0abf6f830c
commit 6a127810c0
3 changed files with 68 additions and 1 deletions
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33
extmod/moduhashlib.c
View File

@ -60,9 +60,16 @@
typedef struct _mp_obj_hash_t {
mp_obj_base_t base;
char state[0];
bool final; // if set, update and digest raise an exception
uintptr_t state[0]; // must be aligned to a machine word
} mp_obj_hash_t;
static void uhashlib_ensure_not_final(mp_obj_hash_t *self) {
if (self->final) {
mp_raise_ValueError(MP_ERROR_TEXT("hash is final"));
}
}
#if MICROPY_PY_UHASHLIB_SHA256
STATIC mp_obj_t uhashlib_sha256_update(mp_obj_t self_in, mp_obj_t arg);
@ -78,6 +85,7 @@ STATIC mp_obj_t uhashlib_sha256_make_new(const mp_obj_type_t *type, size_t n_arg
mp_arg_check_num(n_args, n_kw, 0, 1, false);
mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, sizeof(mbedtls_sha256_context));
o->base.type = type;
o->final = false;
mbedtls_sha256_init((mbedtls_sha256_context *)&o->state);
mbedtls_sha256_starts_ret((mbedtls_sha256_context *)&o->state, 0);
if (n_args == 1) {
@ -88,6 +96,7 @@ STATIC mp_obj_t uhashlib_sha256_make_new(const mp_obj_type_t *type, size_t n_arg
STATIC mp_obj_t uhashlib_sha256_update(mp_obj_t self_in, mp_obj_t arg) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
mbedtls_sha256_update_ret((mbedtls_sha256_context *)&self->state, bufinfo.buf, bufinfo.len);
@ -96,6 +105,8 @@ STATIC mp_obj_t uhashlib_sha256_update(mp_obj_t self_in, mp_obj_t arg) {
STATIC mp_obj_t uhashlib_sha256_digest(mp_obj_t self_in) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
self->final = true;
vstr_t vstr;
vstr_init_len(&vstr, 32);
mbedtls_sha256_finish_ret((mbedtls_sha256_context *)&self->state, (unsigned char *)vstr.buf);
@ -110,6 +121,7 @@ STATIC mp_obj_t uhashlib_sha256_make_new(const mp_obj_type_t *type, size_t n_arg
mp_arg_check_num(n_args, n_kw, 0, 1, false);
mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, sizeof(CRYAL_SHA256_CTX));
o->base.type = type;
o->final = false;
sha256_init((CRYAL_SHA256_CTX *)o->state);
if (n_args == 1) {
uhashlib_sha256_update(MP_OBJ_FROM_PTR(o), args[0]);
@ -119,6 +131,7 @@ STATIC mp_obj_t uhashlib_sha256_make_new(const mp_obj_type_t *type, size_t n_arg
STATIC mp_obj_t uhashlib_sha256_update(mp_obj_t self_in, mp_obj_t arg) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
sha256_update((CRYAL_SHA256_CTX *)self->state, bufinfo.buf, bufinfo.len);
@ -127,6 +140,8 @@ STATIC mp_obj_t uhashlib_sha256_update(mp_obj_t self_in, mp_obj_t arg) {
STATIC mp_obj_t uhashlib_sha256_digest(mp_obj_t self_in) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
self->final = true;
vstr_t vstr;
vstr_init_len(&vstr, SHA256_BLOCK_SIZE);
sha256_final((CRYAL_SHA256_CTX *)self->state, (byte *)vstr.buf);
@ -160,6 +175,7 @@ STATIC mp_obj_t uhashlib_sha1_make_new(const mp_obj_type_t *type, size_t n_args,
mp_arg_check_num(n_args, n_kw, 0, 1, false);
mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, sizeof(SHA1_CTX));
o->base.type = type;
o->final = false;
SHA1_Init((SHA1_CTX *)o->state);
if (n_args == 1) {
uhashlib_sha1_update(MP_OBJ_FROM_PTR(o), args[0]);
@ -169,6 +185,7 @@ STATIC mp_obj_t uhashlib_sha1_make_new(const mp_obj_type_t *type, size_t n_args,
STATIC mp_obj_t uhashlib_sha1_update(mp_obj_t self_in, mp_obj_t arg) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
SHA1_Update((SHA1_CTX *)self->state, bufinfo.buf, bufinfo.len);
@ -177,6 +194,8 @@ STATIC mp_obj_t uhashlib_sha1_update(mp_obj_t self_in, mp_obj_t arg) {
STATIC mp_obj_t uhashlib_sha1_digest(mp_obj_t self_in) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
self->final = true;
vstr_t vstr;
vstr_init_len(&vstr, SHA1_SIZE);
SHA1_Final((byte *)vstr.buf, (SHA1_CTX *)self->state);
@ -196,6 +215,7 @@ STATIC mp_obj_t uhashlib_sha1_make_new(const mp_obj_type_t *type, size_t n_args,
mp_arg_check_num(n_args, n_kw, 0, 1, false);
mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, sizeof(mbedtls_sha1_context));
o->base.type = type;
o->final = false;
mbedtls_sha1_init((mbedtls_sha1_context *)o->state);
mbedtls_sha1_starts_ret((mbedtls_sha1_context *)o->state);
if (n_args == 1) {
@ -206,6 +226,7 @@ STATIC mp_obj_t uhashlib_sha1_make_new(const mp_obj_type_t *type, size_t n_args,
STATIC mp_obj_t uhashlib_sha1_update(mp_obj_t self_in, mp_obj_t arg) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
mbedtls_sha1_update_ret((mbedtls_sha1_context *)self->state, bufinfo.buf, bufinfo.len);
@ -214,6 +235,8 @@ STATIC mp_obj_t uhashlib_sha1_update(mp_obj_t self_in, mp_obj_t arg) {
STATIC mp_obj_t uhashlib_sha1_digest(mp_obj_t self_in) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
self->final = true;
vstr_t vstr;
vstr_init_len(&vstr, 20);
mbedtls_sha1_finish_ret((mbedtls_sha1_context *)self->state, (byte *)vstr.buf);
@ -247,6 +270,7 @@ STATIC mp_obj_t uhashlib_md5_make_new(const mp_obj_type_t *type, size_t n_args,
mp_arg_check_num(n_args, n_kw, 0, 1, false);
mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, sizeof(MD5_CTX));
o->base.type = type;
o->final = false;
MD5_Init((MD5_CTX *)o->state);
if (n_args == 1) {
uhashlib_md5_update(MP_OBJ_FROM_PTR(o), args[0]);
@ -256,6 +280,7 @@ STATIC mp_obj_t uhashlib_md5_make_new(const mp_obj_type_t *type, size_t n_args,
STATIC mp_obj_t uhashlib_md5_update(mp_obj_t self_in, mp_obj_t arg) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
MD5_Update((MD5_CTX *)self->state, bufinfo.buf, bufinfo.len);
@ -264,6 +289,8 @@ STATIC mp_obj_t uhashlib_md5_update(mp_obj_t self_in, mp_obj_t arg) {
STATIC mp_obj_t uhashlib_md5_digest(mp_obj_t self_in) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
self->final = true;
vstr_t vstr;
vstr_init_len(&vstr, MD5_SIZE);
MD5_Final((byte *)vstr.buf, (MD5_CTX *)self->state);
@ -283,6 +310,7 @@ STATIC mp_obj_t uhashlib_md5_make_new(const mp_obj_type_t *type, size_t n_args,
mp_arg_check_num(n_args, n_kw, 0, 1, false);
mp_obj_hash_t *o = m_new_obj_var(mp_obj_hash_t, char, sizeof(mbedtls_md5_context));
o->base.type = type;
o->final = false;
mbedtls_md5_init((mbedtls_md5_context *)o->state);
mbedtls_md5_starts_ret((mbedtls_md5_context *)o->state);
if (n_args == 1) {
@ -293,6 +321,7 @@ STATIC mp_obj_t uhashlib_md5_make_new(const mp_obj_type_t *type, size_t n_args,
STATIC mp_obj_t uhashlib_md5_update(mp_obj_t self_in, mp_obj_t arg) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(arg, &bufinfo, MP_BUFFER_READ);
mbedtls_md5_update_ret((mbedtls_md5_context *)self->state, bufinfo.buf, bufinfo.len);
@ -301,6 +330,8 @@ STATIC mp_obj_t uhashlib_md5_update(mp_obj_t self_in, mp_obj_t arg) {
STATIC mp_obj_t uhashlib_md5_digest(mp_obj_t self_in) {
mp_obj_hash_t *self = MP_OBJ_TO_PTR(self_in);
uhashlib_ensure_not_final(self);
self->final = true;
vstr_t vstr;
vstr_init_len(&vstr, 16);
mbedtls_md5_finish_ret((mbedtls_md5_context *)self->state, (byte *)vstr.buf);

35
tests/extmod/uhashlib_final.py Normal file
View File

@ -0,0 +1,35 @@
try:
import uhashlib
except ImportError:
print("SKIP")
raise SystemExit
for algo_name in ("md5", "sha1", "sha256"):
algo = getattr(uhashlib, algo_name, None)
if not algo:
continue
# Running .digest() several times in row is not supported.
h = algo(b"123")
h.digest()
try:
h.digest()
print("fail")
except ValueError:
# Expected path, don't print anything so test output is the
# same even if the algorithm is not implemented on the port.
pass
# Partial digests are not supported.
h = algo(b"123")
h.digest()
try:
h.update(b"456")
print("fail")
except ValueError:
# Expected path, don't print anything so test output is the
# same even if the algorithm is not implemented on the port.
pass
print("done")

1
tests/extmod/uhashlib_final.py.exp Normal file
View File

@ -0,0 +1 @@
done