Check for EVP_MD being NULL inside ssl. #18784
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Fix multiple places that could potentially segfault if memory allocations fail. e.g. ssl_load_ciphers() could fail while calling ssl_evp_md_fetch(). Found by openssl#18355
slontis
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beldmit
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Jul 12, 2022
paulidale
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Jul 12, 2022
| if (EVP_MD_is_a(ssl_md(s->ctx, tmp->algorithm2), | ||
| OSSL_DIGEST_NAME_SHA2_256)) { | ||
| if (md != NULL | ||
| && EVP_MD_is_a(md, OSSL_DIGEST_NAME_SHA2_256)) { |
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I wonder if EVP_MD_is_a and friends should return false when passed a NULL pointer? Some functions do, some don't.
paulidale
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| @@ -257,13 +257,17 @@ int tls13_generate_master_secret(SSL *s, unsigned char *out, | |||
| size_t tls13_final_finish_mac(SSL *s, const char *str, size_t slen, | |||
| unsigned char *out) | |||
| { | |||
| const char *mdname = EVP_MD_get0_name(ssl_handshake_md(s)); | |||
| const EVP_MD *md = ssl_handshake_md(s); | |||
| const char *mdname = EVP_MD_get0_name(md); | |||
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Don't we need a NULL check here?
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It looks like EVP_MD_get0_name returns NULL if its argument is NULL, so this should be OK.
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Safer to check it nonetheless. There is no telling what changes will be made in the future that break this assumption.
For example, EVP_MD_CTX_get_size() never used to return a failure -- it could as of 3.0.
hlandau
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Jul 12, 2022
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openssl-machine
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This pull request is ready to merge |
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Merged to master and 3.0. Thank you. |
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Fix multiple places that could potentially segfault if memory allocations fail. e.g. ssl_load_ciphers() could fail while calling ssl_evp_md_fetch(). Found by #18355 Reviewed-by: Paul Dale <pauli@openssl.org> Reviewed-by: Hugo Landau <hlandau@openssl.org> Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com> (Merged from #18784) (cherry picked from commit b740012)
openssl-machine
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Fix multiple places that could potentially segfault if memory allocations fail. e.g. ssl_load_ciphers() could fail while calling ssl_evp_md_fetch(). Found by #18355 Reviewed-by: Paul Dale <pauli@openssl.org> Reviewed-by: Hugo Landau <hlandau@openssl.org> Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com> (Merged from #18784)
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Fix multiple places that could potentially segfault if memory allocations fail. e.g. ssl_load_ciphers() could fail while calling ssl_evp_md_fetch(). Found by openssl#18355 Reviewed-by: Paul Dale <pauli@openssl.org> Reviewed-by: Hugo Landau <hlandau@openssl.org> Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com> (Merged from openssl#18784)
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Fix multiple places that could potentially segfault if memory
allocations fail. e.g. ssl_load_ciphers() could fail while calling
ssl_evp_md_fetch().
Found by #18355
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