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gbytearray: Do not accept too large byte arrays

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GByteArray uses guint for storing the length of the byte array, but it
also has a constructor (g_byte_array_new_take) that takes length as a
gsize. gsize may be larger than guint (64 bits for gsize vs 32 bits
for guint). It is possible to call the function with a value greater
than G_MAXUINT, which will result in silent length truncation. This
may happen as a result of unreffing GBytes into GByteArray, so rather
be loud about it.

(Test case tweaked by Philip Withnall.)
This commit is contained in:
Krzesimir Nowak
2021-02-10 23:51:07 +01:00
committed by Philip Withnall
parent efe49e46cf
commit acb7b0ec69
3 changed files with 43 additions and 1 deletions
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6
glib/garray.c
View File

@@ -2261,6 +2261,10 @@ g_byte_array_steal (GByteArray *array,
* Create byte array containing the data. The data will be owned by the array
* and will be freed with g_free(), i.e. it could be allocated using g_strdup().
*
* Do not use it if @len is greater than %G_MAXUINT. #GByteArray
* stores the length of its data in #guint, which may be shorter than
* #gsize.
*
* Since: 2.32
*
* Returns: (transfer full): a new #GByteArray
@@ -2272,6 +2276,8 @@ g_byte_array_new_take (guint8 *data,
GByteArray *array;
GRealArray *real;
g_return_val_if_fail (len <= G_MAXUINT, NULL);
array = g_byte_array_new ();
real = (GRealArray *)array;
g_assert (real->data == NULL);

4
glib/gbytes.c
View File

@@ -519,6 +519,10 @@ g_bytes_unref_to_data (GBytes *bytes,
* g_bytes_new(), g_bytes_new_take() or g_byte_array_free_to_bytes(). In all
* other cases the data is copied.
*
* Do not use it if @bytes contains more than %G_MAXUINT
* bytes. #GByteArray stores the length of its data in #guint, which
* may be shorter than #gsize, that @bytes is using.
*
* Returns: (transfer full): a new mutable #GByteArray containing the same byte data
*
* Since: 2.32

34
glib/tests/bytes.c
View File

@@ -10,7 +10,6 @@
*/
#undef G_DISABLE_ASSERT
#undef G_LOG_DOMAIN
#include <stdio.h>
#include <stdlib.h>
@@ -333,6 +332,38 @@ test_to_array_transferred (void)
g_byte_array_unref (array);
}
static void
test_to_array_transferred_oversize (void)
{
g_test_message ("g_bytes_unref_to_array() can only take GBytes up to "
"G_MAXUINT in length; test that longer ones are rejected");
if (sizeof (guint) >= sizeof (gsize))
{
g_test_skip ("Skipping test as guint is not smaller than gsize");
}
else if (g_test_undefined ())
{
GByteArray *array = NULL;
GBytes *bytes = NULL;
gpointer data = g_memdup2 (NYAN, N_NYAN);
gsize len = ((gsize) G_MAXUINT) + 1;
bytes = g_bytes_new_take (data, len);
g_test_expect_message (G_LOG_DOMAIN, G_LOG_LEVEL_CRITICAL,
"g_byte_array_new_take: assertion 'len <= G_MAXUINT' failed");
array = g_bytes_unref_to_array (g_steal_pointer (&bytes));
g_test_assert_expected_messages ();
g_assert_null (array);
g_free (data);
}
else
{
g_test_skip ("Skipping test as testing undefined behaviour is disabled");
}
}
static void
test_to_array_two_refs (void)
{
@@ -408,6 +439,7 @@ main (int argc, char *argv[])
g_test_add_func ("/bytes/to-data/two-refs", test_to_data_two_refs);
g_test_add_func ("/bytes/to-data/non-malloc", test_to_data_non_malloc);
g_test_add_func ("/bytes/to-array/transferred", test_to_array_transferred);
g_test_add_func ("/bytes/to-array/transferred/oversize", test_to_array_transferred_oversize);
g_test_add_func ("/bytes/to-array/two-refs", test_to_array_two_refs);
g_test_add_func ("/bytes/to-array/non-malloc", test_to_array_non_malloc);
g_test_add_func ("/bytes/null", test_null);