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Fix GH-18173: ext/hash relies on implementation-defined malloc alignment #20

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Fix GH-18173: ext/hash relies on implementation-defined malloc alignment #20

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20 changes: 10 additions & 10 deletions ext/hash/hash.c
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Original file line number Diff line number Diff line change
Expand Up @@ -388,7 +388,7 @@ static void php_hash_do_hash(
}
php_stream_close(stream);
if (n < 0) {
efree(context);
php_hash_free_context(ops, context);
RETURN_FALSE;
}
} else {
Expand All @@ -397,7 +397,7 @@ static void php_hash_do_hash(

digest = zend_string_alloc(ops->digest_size, 0);
ops->hash_final((unsigned char *) ZSTR_VAL(digest), context);
efree(context);
php_hash_free_context(ops, context);

if (raw_output) {
ZSTR_VAL(digest)[ops->digest_size] = 0;
Expand Down Expand Up @@ -536,7 +536,7 @@ static void php_hash_do_hash_hmac(
}
php_stream_close(stream);
if (n < 0) {
efree(context);
php_hash_free_context(ops, context);
efree(K);
zend_string_efree(digest);
RETURN_FALSE;
Expand All @@ -554,7 +554,7 @@ static void php_hash_do_hash_hmac(
/* Zero the key */
ZEND_SECURE_ZERO(K, ops->block_size);
efree(K);
efree(context);
php_hash_free_context(ops, context);

if (raw_output) {
ZSTR_VAL(digest)[ops->digest_size] = 0;
Expand Down Expand Up @@ -815,7 +815,7 @@ PHP_FUNCTION(hash_final)
ZSTR_VAL(digest)[digest_len] = 0;

/* Invalidate the object from further use */
efree(hash->context);
php_hash_free_context(hash->ops, hash->context);
hash->context = NULL;

if (raw_output) {
Expand Down Expand Up @@ -973,7 +973,7 @@ PHP_FUNCTION(hash_hkdf)
ZEND_SECURE_ZERO(digest, ops->digest_size);
ZEND_SECURE_ZERO(prk, ops->digest_size);
efree(K);
efree(context);
php_hash_free_context(ops, context);
efree(prk);
efree(digest);
ZSTR_VAL(returnval)[length] = 0;
Expand Down Expand Up @@ -1089,7 +1089,7 @@ PHP_FUNCTION(hash_pbkdf2)
efree(K1);
efree(K2);
efree(computed_salt);
efree(context);
php_hash_free_context(ops, context);
efree(digest);
efree(temp);

Expand Down Expand Up @@ -1356,7 +1356,7 @@ PHP_FUNCTION(mhash_keygen_s2k)
RETVAL_STRINGL(key, bytes);
ZEND_SECURE_ZERO(key, bytes);
efree(digest);
efree(context);
php_hash_free_context(ops, context);
efree(key);
}
}
Expand Down Expand Up @@ -1386,7 +1386,7 @@ static void php_hashcontext_dtor(zend_object *obj) {
php_hashcontext_object *hash = php_hashcontext_from_object(obj);

if (hash->context) {
efree(hash->context);
php_hash_free_context(hash->ops, hash->context);
hash->context = NULL;
}

Expand Down Expand Up @@ -1422,7 +1422,7 @@ static zend_object *php_hashcontext_clone(zend_object *zobj) {
newobj->ops->hash_init(newobj->context, NULL);

if (SUCCESS != newobj->ops->hash_copy(newobj->ops, oldobj->context, newobj->context)) {
efree(newobj->context);
php_hash_free_context(newobj->ops, newobj->context);
newobj->context = NULL;
return znew;
}
Expand Down
6 changes: 4 additions & 2 deletions ext/hash/hash_xxhash.c
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Original file line number Diff line number Diff line change
Expand Up @@ -152,7 +152,8 @@ const php_hash_ops php_hash_xxh3_64_ops = {
8,
8,
sizeof(PHP_XXH3_64_CTX),
0
0,
64
};

typedef XXH_errorcode (*xxh3_reset_with_secret_func_t)(XXH3_state_t*, const void*, size_t);
Expand Down Expand Up @@ -257,7 +258,8 @@ const php_hash_ops php_hash_xxh3_128_ops = {
16,
8,
sizeof(PHP_XXH3_128_CTX),
0
0,
64
};

PHP_HASH_API void PHP_XXH3_128_Init(PHP_XXH3_128_CTX *ctx, HashTable *args)
Expand Down
18 changes: 18 additions & 0 deletions ext/hash/php_hash.h
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Original file line number Diff line number Diff line change
Expand Up @@ -60,6 +60,7 @@ typedef struct _php_hash_ops {
size_t block_size;
size_t context_size;
unsigned is_crypto: 1;
size_t context_align;
} php_hash_ops;

struct _php_hashcontext_object {
Expand Down Expand Up @@ -163,9 +164,26 @@ PHP_HASH_API hash_spec_result php_hash_unserialize_spec(php_hashcontext_object *

static inline void *php_hash_alloc_context(const php_hash_ops *ops) {
/* Zero out context memory so serialization doesn't expose internals */
if (ops->context_align > 0) {
size_t align = ops->context_align;
char *base = ecalloc(1, ops->context_size + align);
size_t offset = align - ((uintptr_t)base & (align - 1));
char *ptr = base + offset;
ptr[-1] = (char)offset;
return ptr;
}
return ecalloc(1, ops->context_size);
}

static inline void php_hash_free_context(const php_hash_ops *ops, void *ctx) {
if (ops->context_align > 0) {
unsigned char offset = ((unsigned char *)ctx)[-1];
efree((char *)ctx - offset);
return;
}
efree(ctx);
}

static inline void php_hash_bin2hex(char *out, const unsigned char *in, size_t in_len)
{
static const char hexits[17] = "0123456789abcdef";
Expand Down
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