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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"_ldap.str2dn() segfaults when called with empty string","articleBody":"Issue description:\r\n\r\n`_ldap.str2dn` segfaults with a NULL pointer deref when called with an empty string as argument. `ldap_bv2dn` return success for an empty string and sets `dn` pointer to NULL. Debug builds of OpenLDAP fail with an assertion error `getdn.c:710: ldap_bv2dn_x: Assertion bvin-\u003ebv_val != NULL failed.`. Our code does not handle NULL `dn` and empty string correctly. Fix is trivial.\r\n\r\n```\r\n\u003e\u003e\u003e _ldap.str2dn(\"\")\r\n\r\nProgram received signal SIGSEGV, Segmentation fault.\r\nl_ldap_str2dn (unused=\u003coptimized out\u003e, args=\u003coptimized out\u003e) at Modules/functions.c:118\r\nDownloading source file /usr/src/debug/python-ldap-3.4.3-2.fc38.x86_64/Modules/functions.c\r\n118         for (i = 0; dn[i]; i++) {                                                                                                                            \r\n(gdb) bt\r\n#0  l_ldap_str2dn (unused=\u003coptimized out\u003e, args=\u003coptimized out\u003e) at Modules/functions.c:118\r\n#1  0x00007ffff7bcef08 in cfunction_call (func=0x7fffe9e2f240, args=\u003coptimized out\u003e, kwargs=\u003coptimized out\u003e)\r\n    at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Objects/methodobject.c:553\r\n#2  0x00007ffff7bb2173 in _PyObject_MakeTpCall (tstate=0x7ffff7f10538 \u003c_PyRuntime+166328\u003e, callable=0x7fffe9e2f240, args=\u003coptimized out\u003e, nargs=1, \r\n    keywords=\u003coptimized out\u003e) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Objects/call.c:214\r\n#3  0x00007ffff7bba996 in _PyEval_EvalFrameDefault (tstate=\u003coptimized out\u003e, frame=\u003coptimized out\u003e, throwflag=\u003coptimized out\u003e)\r\n    at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/ceval.c:4760\r\n#4  0x00007ffff7bb6bba in _PyEval_EvalFrame (throwflag=0, frame=0x7ffff763d020, tstate=0x7ffff7f10538 \u003c_PyRuntime+166328\u003e)\r\n    at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Include/internal/pycore_ceval.h:73\r\n#5  _PyEval_Vector (tstate=tstate@entry=0x7ffff7f10538 \u003c_PyRuntime+166328\u003e, func=func@entry=0x7fffe9f8c540, locals=locals@entry=0x7ffff773b200, \r\n    args=args@entry=0x0, argcount=argcount@entry=0, kwnames=kwnames@entry=0x0) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/ceval.c:6425\r\n#6  0x00007ffff7c3b15c in PyEval_EvalCode (co=0x7fffe9d9fb40, globals=\u003coptimized out\u003e, locals=0x7ffff773b200)\r\n    at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/ceval.c:1140\r\n#7  0x00007ffff7c58413 in run_eval_code_obj (tstate=tstate@entry=0x7ffff7f10538 \u003c_PyRuntime+166328\u003e, co=co@entry=0x7fffe9d9fb40, \r\n    globals=globals@entry=0x7ffff773b200, locals=locals@entry=0x7ffff773b200) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/pythonrun.c:1710\r\n#8  0x00007ffff7c54a7a in run_mod (mod=mod@entry=0x55555572eba8, filename=filename@entry=0x7ffff76ec230, globals=0x7ffff773b200, locals=0x7ffff773b200, \r\n    flags=flags@entry=0x7fffffffd068, arena=arena@entry=0x7ffff765f990) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/pythonrun.c:1731\r\n#9  0x00007ffff7b99732 in PyRun_InteractiveOneObjectEx (fp=fp@entry=0x7ffff79f6aa0 \u003c_IO_2_1_stdin_\u003e, filename=filename@entry=0x7ffff76ec230, \r\n    flags=flags@entry=0x7fffffffd068) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/pythonrun.c:261\r\n#10 0x00007ffff7b998d2 in _PyRun_InteractiveLoopObject (fp=0x7ffff79f6aa0 \u003c_IO_2_1_stdin_\u003e, filename=0x7ffff76ec230, flags=0x7fffffffd068)\r\n    at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/pythonrun.c:138\r\n#11 0x00007ffff7b2688b in _PyRun_AnyFileObject (fp=0x7ffff79f6aa0 \u003c_IO_2_1_stdin_\u003e, filename=0x7ffff76ec230, closeit=0, flags=0x7fffffffd068)\r\n    at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/pythonrun.c:73\r\n#12 0x00007ffff7b99a4f in PyRun_AnyFileExFlags (fp=0x7ffff79f6aa0 \u003c_IO_2_1_stdin_\u003e, filename=\u003coptimized out\u003e, closeit=0, flags=0x7fffffffd068)\r\n    at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Python/pythonrun.c:105\r\n#13 0x00007ffff7b22793 in pymain_run_stdin (config=0x7ffff7ef6580 \u003c_PyRuntime+59904\u003e) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Modules/main.c:509\r\n#14 pymain_run_python (exitcode=0x7fffffffd060) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Modules/main.c:604\r\n#15 Py_RunMain () at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Modules/main.c:680\r\n#16 0x00007ffff7c2b48b in Py_BytesMain (argc=\u003coptimized out\u003e, argv=\u003coptimized out\u003e) at /usr/src/debug/python3.11-3.11.6-1.fc38.x86_64/Modules/main.c:734\r\n#17 0x00007ffff7849b8a in __libc_start_call_main (main=main@entry=0x555555555160 \u003cmain\u003e, argc=argc@entry=1, argv=argv@entry=0x7fffffffd2c8)\r\n    at ../sysdeps/nptl/libc_start_call_main.h:58\r\n#18 0x00007ffff7849c4b in __libc_start_main_impl (main=0x555555555160 \u003cmain\u003e, argc=1, argv=0x7fffffffd2c8, init=\u003coptimized out\u003e, fini=\u003coptimized out\u003e, \r\n    rtld_fini=\u003coptimized out\u003e, stack_end=0x7fffffffd2b8) at ../csu/libc-start.c:360\r\n#19 0x0000555555555095 in _start ()\r\n(gdb) p dn\r\n$1 = (LDAPDN) 0x0\r\n```\r\n\r\n\r\n\r\n\r\nSteps to reproduce: \r\n\r\n```\r\nimport _ldap\r\n_ldap.str2dn(\"\")\r\n```\r\n\r\n\r\nOperating system: \r\nany\r\n\r\nPython version: \r\nany\r\n\r\npython-ldap version: \r\n3.4.3","author":{"url":"https://github.com/tiran","@type":"Person","name":"tiran"},"datePublished":"2023-11-15T06:00:32.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0},"url":"https://github.com/549/python-ldap/issues/549"}