← index #17719Issue #17728
Off-topic · high · value 4.726
QUERY · ISSUE

crash in ssl module

openby jepleropened 2025-07-19updated 2025-07-19
bug

Port, board and/or hardware

unix, coverage build

MicroPython version

MicroPython v1.26.0-preview.387.g67acac257f.dirty on 2025-07-19; linux [GCC 12.2.0] version

Reproduction

Run the following code:

import io
import ssl

class TestSocket(io.IOBase):
    def write(self, buf):
        return len(buf)

    def readinto(self, buf):
        return 0

    def ioctl(self, cmd, arg):
        print("TestSocket.ioctl", cmd, arg)
        return 0

    def setblocking(self, value):
        print("TestSocket.setblocking({})".format(value))


ss = ssl.wrap_socket(TestSocket(), server_side=1, do_handshake=0)
ss.close()
ss.setblocking(0)

Expected behaviour

When calling setblocking on a closed ssl socket, no crash occurs

Observed behaviour

segmentation fault. gdb says

Program received signal SIGSEGV, Segmentation fault.
mp_obj_get_type (o_in=o_in@entry=0x0) at ../../py/obj.c:61
61	        return o->type;
(gdb) where
#0  mp_obj_get_type (o_in=o_in@entry=0x0) at ../../py/obj.c:61
#1  0x00005555555e8ed0 in mp_load_method_maybe (obj=obj@entry=0x0, 
    attr=attr@entry=745, dest=dest@entry=0x7fffffffd870)
    at ../../py/runtime.c:1196
#2  0x00005555555e96c6 in mp_load_method (base=0x0, attr=attr@entry=745, 
    dest=dest@entry=0x7fffffffd870) at ../../py/runtime.c:1239
#3  0x000055555563c7f2 in socket_setblocking (self_in=<optimized out>, 
    flag_in=0xe) at ../../extmod/modtls_mbedtls.c:778

Additional Information

This method, and perhaps other ones, needs to check for a NULL o->sock.

Code of Conduct

Yes, I agree

CANDIDATE · ISSUE

segfault with improper use of super()

openby jepleropened 2025-07-20updated 2025-07-20
bug

Port, board and/or hardware

unix, coverage build

MicroPython version

MicroPython v1.26.0-preview.387.ge4e97f5aa7.dirty on 2025-07-20; linux [GCC 12.2.0] version

Reproduction

Run the following code:

import framebuf

class FB(framebuf.FrameBuffer):
    def __init__(self, n):
        self = n
        super().__init__(bytearray(2 * n * n), n, n, framebuf.RGB565)

fb = FB(n=3)

Expected behaviour

super() should not segfault.

Observed behaviour

crash in native_base_init_wrapper

Program received signal SIGSEGV, Segmentation fault.
0x00005555556120c7 in native_base_init_wrapper (n_args=5, args=0x7fffffffd6c0, 
    kw_args=0x7fffffffd510) at ../../py/objtype.c:91
91	    instance_count_native_bases(self->base.type, &native_base);
(gdb) p self
$1 = (mp_obj_instance_t *) 0x7

Additional Information

This is a minimized version of a script produced by fuzzing micropython.

Code of Conduct

Yes, I agree

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