Fix error handling in ASN1_mbstring_ncopy

[bernd-edlinger]

Sometimes the error handling returns an ASN1_STRING object in *out although that was not passed in by the caller, and sometimes the error handling deletes the ASN1_STRING but forgets to clear the *out parameter. Therfore the caller has no chance to know, if the leaked object in *out shall be deleted or not.
This may cause a use-after-free error e.g. in asn1_str2type:

==63312==ERROR: AddressSanitizer: heap-use-after-free on address 0x603000073280 at pc 0x7f2652e93b08 bp 0x7ffe0e1951c0 sp 0x7ffe0e1951b0 READ of size 8 at 0x603000073280 thread T0
#0 0x7f2652e93b07 in asn1_string_embed_free crypto/asn1/asn1_lib.c:354
#1 0x7f2652eb521a in asn1_primitive_free crypto/asn1/tasn_fre.c:204
#2 0x7f2652eb50a9 in asn1_primitive_free crypto/asn1/tasn_fre.c:199
#3 0x7f2652eb5b67 in ASN1_item_free crypto/asn1/tasn_fre.c:20
#4 0x7f2652e8e13b in asn1_str2type crypto/asn1/asn1_gen.c:740
#5 0x7f2652e8e13b in generate_v3 crypto/asn1/asn1_gen.c:137
#6 0x7f2652e9166c in ASN1_generate_v3 crypto/asn1/asn1_gen.c:92
#7 0x7f2653307b9b in do_othername crypto/x509v3/v3_alt.c:577
#8 0x7f2653307b9b in a2i_GENERAL_NAME crypto/x509v3/v3_alt.c:492
#9 0x7f26533087c2 in v2i_subject_alt crypto/x509v3/v3_alt.c:327
#10 0x7f26533107fc in do_ext_nconf crypto/x509v3/v3_conf.c:100
#11 0x7f2653310f33 in X509V3_EXT_nconf crypto/x509v3/v3_conf.c:45
#12 0x7f2653311426 in X509V3_EXT_add_nconf_sk crypto/x509v3/v3_conf.c:312
#13 0x7f265331170c in X509V3_EXT_REQ_add_nconf crypto/x509v3/v3_conf.c:360
#14 0x564ed19d5f25 in req_main apps/req.c:806
#15 0x564ed19b8de0 in do_cmd apps/openssl.c:564
#16 0x564ed1985165 in main apps/openssl.c:183
#17 0x7f2651c4a082 in __libc_start_main ../csu/libc-start.c:308
#18 0x564ed1985acd in _start (/home/ed/OPCToolboxV5/Source/Core/OpenSSL/openssl/apps/openssl+0x139acd)

0x603000073280 is located 16 bytes inside of 24-byte region [0x603000073270,0x603000073288) freed by thread T0 here:
#0 0x7f265413440f in __interceptor_free ../../../../src/libsanitizer/asan/asan_malloc_linux.cc:122
#1 0x7f265315a429 in CRYPTO_free crypto/mem.c:311
#2 0x7f265315a429 in CRYPTO_free crypto/mem.c:300
#3 0x7f2652e757b9 in ASN1_mbstring_ncopy crypto/asn1/a_mbstr.c:191
#4 0x7f2652e75ec5 in ASN1_mbstring_copy crypto/asn1/a_mbstr.c:38
#5 0x7f2652e8e227 in asn1_str2type crypto/asn1/asn1_gen.c:681
#6 0x7f2652e8e227 in generate_v3 crypto/asn1/asn1_gen.c:137
#7 0x7f2652e9166c in ASN1_generate_v3 crypto/asn1/asn1_gen.c:92
#8 0x7f2653307b9b in do_othername crypto/x509v3/v3_alt.c:577
#9 0x7f2653307b9b in a2i_GENERAL_NAME crypto/x509v3/v3_alt.c:492
#10 0x7f26533087c2 in v2i_subject_alt crypto/x509v3/v3_alt.c:327
#11 0x7f26533107fc in do_ext_nconf crypto/x509v3/v3_conf.c:100
#12 0x7f2653310f33 in X509V3_EXT_nconf crypto/x509v3/v3_conf.c:45
#13 0x7f2653311426 in X509V3_EXT_add_nconf_sk crypto/x509v3/v3_conf.c:312
#14 0x7f265331170c in X509V3_EXT_REQ_add_nconf crypto/x509v3/v3_conf.c:360
#15 0x564ed19d5f25 in req_main apps/req.c:806
#16 0x564ed19b8de0 in do_cmd apps/openssl.c:564
#17 0x564ed1985165 in main apps/openssl.c:183
#18 0x7f2651c4a082 in __libc_start_main ../csu/libc-start.c:308

previously allocated by thread T0 here:
#0 0x7f2654134808 in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cc:144
#1 0x7f265315a4fd in CRYPTO_malloc crypto/mem.c:221
#2 0x7f265315a4fd in CRYPTO_malloc crypto/mem.c:198
#3 0x7f265315a945 in CRYPTO_zalloc crypto/mem.c:236
#4 0x7f2652e939a4 in ASN1_STRING_type_new crypto/asn1/asn1_lib.c:341
#5 0x7f2652e74e51 in ASN1_mbstring_ncopy crypto/asn1/a_mbstr.c:150
#6 0x7f2652e75ec5 in ASN1_mbstring_copy crypto/asn1/a_mbstr.c:38
#7 0x7f2652e8e227 in asn1_str2type crypto/asn1/asn1_gen.c:681
#8 0x7f2652e8e227 in generate_v3 crypto/asn1/asn1_gen.c:137
#9 0x7f2652e9166c in ASN1_generate_v3 crypto/asn1/asn1_gen.c:92
#10 0x7f2653307b9b in do_othername crypto/x509v3/v3_alt.c:577
#11 0x7f2653307b9b in a2i_GENERAL_NAME crypto/x509v3/v3_alt.c:492
#12 0x7f26533087c2 in v2i_subject_alt crypto/x509v3/v3_alt.c:327
#13 0x7f26533107fc in do_ext_nconf crypto/x509v3/v3_conf.c:100
#14 0x7f2653310f33 in X509V3_EXT_nconf crypto/x509v3/v3_conf.c:45
#15 0x7f2653311426 in X509V3_EXT_add_nconf_sk crypto/x509v3/v3_conf.c:312
#16 0x7f265331170c in X509V3_EXT_REQ_add_nconf crypto/x509v3/v3_conf.c:360
#17 0x564ed19d5f25 in req_main apps/req.c:806
#18 0x564ed19b8de0 in do_cmd apps/openssl.c:564
#19 0x564ed1985165 in main apps/openssl.c:183
#20 0x7f2651c4a082 in __libc_start_main ../csu/libc-start.c:308

Checklist

• documentation is added or updated
• tests are added or updated

[jamuir]

LGTM.

Can you provide some info on what you have done to test your changes?

[openssl-machine]

This pull request is ready to merge

[t8m]

Merged to the master and 3.2 branches. Thank you for your contribution.

@bernd-edlinger This doesn't apply to 3.1, 3.0 cleanly. Is this just a recent regression from refactoring of ASN1_mbstring_ncopy()?

[bernd-edlinger]

No, I found it originally while doing error injection tests on my 1.1.1 feature branch,
so it is unlikely that it is not affecting 3.0 and 3.1 as well.
I will look into creating a back-port for those versions.

[bernd-edlinger]

Backport in #23165