diff options
| -rw-r--r-- | Doc/library/struct.rst | 6 | ||||
| -rw-r--r-- | Lib/test/test_struct.py | 34 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2018-03-11-00-20-26.bpo-30249.KSkgLB.rst | 2 | ||||
| -rw-r--r-- | Modules/_struct.c | 35 | ||||
| -rw-r--r-- | Modules/clinic/_struct.c.h | 5 |
5 files changed, 67 insertions, 15 deletions
diff --git a/Doc/library/struct.rst b/Doc/library/struct.rst index 2d0866c..d6a3cb7 100644 --- a/Doc/library/struct.rst +++ b/Doc/library/struct.rst @@ -74,8 +74,8 @@ The module defines the following exception and functions: Unpack from *buffer* starting at position *offset*, according to the format string *format*. The result is a tuple even if it contains exactly one - item. The buffer's size in bytes, minus *offset*, must be at least - the size required by the format, as reflected by :func:`calcsize`. + item. The buffer's size in bytes, starting at position *offset*, must be at + least the size required by the format, as reflected by :func:`calcsize`. .. function:: iter_unpack(format, buffer) @@ -428,7 +428,7 @@ The :mod:`struct` module also defines the following type: .. method:: unpack_from(buffer, offset=0) Identical to the :func:`unpack_from` function, using the compiled format. - The buffer's size in bytes, minus *offset*, must be at least + The buffer's size in bytes, starting at position *offset*, must be at least :attr:`size`. diff --git a/Lib/test/test_struct.py b/Lib/test/test_struct.py index 8fd56c9..454082e 100644 --- a/Lib/test/test_struct.py +++ b/Lib/test/test_struct.py @@ -579,14 +579,22 @@ class StructTest(unittest.TestCase): self.check_sizeof('0c', 0) def test_boundary_error_message(self): - regex = ( + regex1 = ( r'pack_into requires a buffer of at least 6 ' r'bytes for packing 1 bytes at offset 5 ' r'\(actual buffer size is 1\)' ) - with self.assertRaisesRegex(struct.error, regex): + with self.assertRaisesRegex(struct.error, regex1): struct.pack_into('b', bytearray(1), 5, 1) + regex2 = ( + r'unpack_from requires a buffer of at least 6 ' + r'bytes for unpacking 1 bytes at offset 5 ' + r'\(actual buffer size is 1\)' + ) + with self.assertRaisesRegex(struct.error, regex2): + struct.unpack_from('b', bytearray(1), 5) + def test_boundary_error_message_with_negative_offset(self): byte_list = bytearray(10) with self.assertRaisesRegex( @@ -599,16 +607,34 @@ class StructTest(unittest.TestCase): 'offset -11 out of range for 10-byte buffer'): struct.pack_into('<B', byte_list, -11, 123) + with self.assertRaisesRegex( + struct.error, + r'not enough data to unpack 4 bytes at offset -2'): + struct.unpack_from('<I', byte_list, -2) + + with self.assertRaisesRegex( + struct.error, + "offset -11 out of range for 10-byte buffer"): + struct.unpack_from('<B', byte_list, -11) + def test_boundary_error_message_with_large_offset(self): # Test overflows cause by large offset and value size (issue 30245) - regex = ( + regex1 = ( r'pack_into requires a buffer of at least ' + str(sys.maxsize + 4) + r' bytes for packing 4 bytes at offset ' + str(sys.maxsize) + r' \(actual buffer size is 10\)' ) - with self.assertRaisesRegex(struct.error, regex): + with self.assertRaisesRegex(struct.error, regex1): struct.pack_into('<I', bytearray(10), sys.maxsize, 1) + regex2 = ( + r'unpack_from requires a buffer of at least ' + str(sys.maxsize + 4) + + r' bytes for unpacking 4 bytes at offset ' + str(sys.maxsize) + + r' \(actual buffer size is 10\)' + ) + with self.assertRaisesRegex(struct.error, regex2): + struct.unpack_from('<I', bytearray(10), sys.maxsize) + def test_issue29802(self): # When the second argument of struct.unpack() was of wrong type # the Struct object was decrefed twice and the reference to diff --git a/Misc/NEWS.d/next/Library/2018-03-11-00-20-26.bpo-30249.KSkgLB.rst b/Misc/NEWS.d/next/Library/2018-03-11-00-20-26.bpo-30249.KSkgLB.rst new file mode 100644 index 0000000..f30dff3 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2018-03-11-00-20-26.bpo-30249.KSkgLB.rst @@ -0,0 +1,2 @@ +Improve struct.unpack_from() exception messages for problems with the buffer +size and offset. diff --git a/Modules/_struct.c b/Modules/_struct.c index 66f74d6..0539706 100644 --- a/Modules/_struct.c +++ b/Modules/_struct.c @@ -1553,7 +1553,8 @@ Return a tuple containing unpacked values. Values are unpacked according to the format string Struct.format. -The buffer's size in bytes, minus offset, must be at least Struct.size. +The buffer's size in bytes, starting at position offset, must be +at least Struct.size. See help(struct) for more on format strings. [clinic start generated code]*/ @@ -1561,16 +1562,38 @@ See help(struct) for more on format strings. static PyObject * Struct_unpack_from_impl(PyStructObject *self, Py_buffer *buffer, Py_ssize_t offset) -/*[clinic end generated code: output=57fac875e0977316 input=97ade52422f8962f]*/ +/*[clinic end generated code: output=57fac875e0977316 input=cafd4851d473c894]*/ { assert(self->s_codes != NULL); - if (offset < 0) + if (offset < 0) { + if (offset + self->s_size > 0) { + PyErr_Format(StructError, + "not enough data to unpack %zd bytes at offset %zd", + self->s_size, + offset); + return NULL; + } + + if (offset + buffer->len < 0) { + PyErr_Format(StructError, + "offset %zd out of range for %zd-byte buffer", + offset, + buffer->len); + return NULL; + } offset += buffer->len; - if (offset < 0 || buffer->len - offset < self->s_size) { + } + + if ((buffer->len - offset) < self->s_size) { PyErr_Format(StructError, - "unpack_from requires a buffer of at least %zd bytes", - self->s_size); + "unpack_from requires a buffer of at least %zu bytes for " + "unpacking %zd bytes at offset %zd " + "(actual buffer size is %zd)", + (size_t)self->s_size + (size_t)offset, + self->s_size, + offset, + buffer->len); return NULL; } return s_unpack_internal(self, (char*)buffer->buf + offset); diff --git a/Modules/clinic/_struct.c.h b/Modules/clinic/_struct.c.h index 6e43215..2ecadfb 100644 --- a/Modules/clinic/_struct.c.h +++ b/Modules/clinic/_struct.c.h @@ -79,7 +79,8 @@ PyDoc_STRVAR(Struct_unpack_from__doc__, "\n" "Values are unpacked according to the format string Struct.format.\n" "\n" -"The buffer\'s size in bytes, minus offset, must be at least Struct.size.\n" +"The buffer\'s size in bytes, starting at position offset, must be\n" +"at least Struct.size.\n" "\n" "See help(struct) for more on format strings."); @@ -302,4 +303,4 @@ exit: return return_value; } -/*[clinic end generated code: output=9119f213a951e4cc input=a9049054013a1b77]*/ +/*[clinic end generated code: output=d79b009652ae0b89 input=a9049054013a1b77]*/ |