OpenSSL extension has many inconsistencies in how errors are handled/reported/propagated

Description

The OpenSSL extension has a number of error-handling inconsistencies that I'm unsure how to handle. We should come to a consensus on how to move forward.
Inconsistencies include:

• Failure reason is not properly communicated to the caller of the function, or can't be distinguished at the call site.
• Some functions emit warnings, some don't.
• Some error-handling paths call php_openssl_store_errors(), some don't.
• Some error-handling paths call php_openssl_store_errors() but still return a success.

This means that partial success isn't obviously reported to the user in some cases, so theoretically they'd always have to check the openssl_error_string() function even if the function returned success, which isn't great.

Some examples

Partial failure example (error stored but loop not aborted, may be intentional but this isn't communicated):
https://github.com/php/php-src/blob/1a9a2c7052e3e22b21c43b31dda9355b6d975f38/ext/openssl/openssl_backend_common.c#L97-L99

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The following two calls may fail because of an inexistent file or some I/O failure
https://github.com/php/php-src/blob/1a9a2c7052e3e22b21c43b31dda9355b6d975f38/ext/openssl/openssl_backend_common.c#L1293-L1297

but at least one of the callsites can't distinguish between different kinds of failure:
https://github.com/php/php-src/blob/1a9a2c7052e3e22b21c43b31dda9355b6d975f38/ext/openssl/openssl.c#L940-L944

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Very similarly to the previous one, different kinds of I/O or validation failures are not distinguished here:

https://github.com/php/php-src/blob/1a9a2c7052e3e22b21c43b31dda9355b6d975f38/ext/openssl/openssl_backend_common.c#L511

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Example of silently swallowing errors without returning a different return value or without emitting a warning; even though this same function emits warnings for other cases:

https://github.com/php/php-src/blob/1a9a2c7052e3e22b21c43b31dda9355b6d975f38/ext/openssl/openssl_backend_common.c#L827-L838

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There's a bunch of calls to php_openssl_conf_get_string that silently ignore errors: because e.g. the key may be optional but note that a configuration error can also result in a silent failure.

For example here:
https://github.com/php/php-src/blob/6a4d0d9456bf872286722ad5f043ad4928e92c9a/ext/openssl/openssl_backend_common.c#L254-L257

but also in various spots in https://github.com/php/php-src/blob/6a4d0d9456bf872286722ad5f043ad4928e92c9a/ext/openssl/openssl_backend_common.c#L293

etc...

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Usage of E_ERROR for some reason, which sometimes could be appropriate but sometimes isn't.
Examples:

https://github.com/php/php-src/blob/1a9a2c7052e3e22b21c43b31dda9355b6d975f38/ext/openssl/openssl_backend_common.c#L742-L747

here we're dealing with allocation failure so it may be appropriate.

However, here it seems inappropriate:

https://github.com/php/php-src/blob/1a9a2c7052e3e22b21c43b31dda9355b6d975f38/ext/openssl/openssl_backend_common.c#L597-L601

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These are just some examples, but shows a much broader problem with the error-handling design of the extension.

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A concrete list found by my tool:

• Function: ASN1_STRING_to_UTF8 | Source: /work/php-src/ext/openssl/openssl_backend_common.c:74 | Return: -1
• Function: BIO_new_mem_buf | Source: /work/php-src/ext/openssl/openssl_backend_common.c:1269 | Return: 0
• Function: BIO_new_mem_buf | Source: /work/php-src/ext/openssl/openssl_backend_common.c:532 | Return: 0
• Function: PEM_read_bio_PrivateKey_ex | Source: /work/php-src/ext/openssl/openssl_backend_common.c:1292 | Return: 0
• Function: X509_LOOKUP_ctrl | Source: /work/php-src/ext/openssl/openssl_backend_common.c:834 | Return: -1
• Function: X509_LOOKUP_ctrl | Source: /work/php-src/ext/openssl/openssl_backend_common.c:834 | Return: 0
• Function: X509_LOOKUP_ctrl | Source: /work/php-src/ext/openssl/openssl_backend_common.c:840 | Return: -1
• Function: X509_LOOKUP_ctrl | Source: /work/php-src/ext/openssl/openssl_backend_common.c:840 | Return: 0
• Function: X509_STORE_add_lookup | Source: /work/php-src/ext/openssl/openssl_backend_common.c:834 | Return: 0
• Function: X509_STORE_add_lookup | Source: /work/php-src/ext/openssl/openssl_backend_common.c:840 | Return: 0
• Function: NCONF_load | Source: /work/php-src/ext/openssl/openssl_backend_common.c:301 | Return: 0
• Function: NCONF_get_string | Source: /work/php-src/ext/openssl/openssl_backend_common.c:255 | Return: 0
• Function: NCONF_get_string | Source: /work/php-src/ext/openssl/openssl_backend_common.c:323 | Return: 0
• Function: NCONF_get_string | Source: /work/php-src/ext/openssl/openssl_backend_common.c:325 | Return: 0
• Function: NCONF_get_string | Source: /work/php-src/ext/openssl/openssl_backend_common.c:327 | Return: 0
• Function: NCONF_get_string | Source: /work/php-src/ext/openssl/openssl_backend_common.c:396 | Return: 0
• Function: NCONF_get_string | Source: /work/php-src/ext/openssl/openssl_backend_common.c:939 | Return: 0
• Function: NCONF_get_string | Source: /work/php-src/ext/openssl/openssl_backend_common.c:949 | Return: 0
• Function: PEM_write_bio_X509 | Source: /work/php-src/ext/openssl/openssl.c:1507 | Return: 0
• Function: PEM_write_bio_X509 | Source: /work/php-src/ext/openssl/openssl.c:1541 | Return: 0
• Function: PEM_write_bio_X509 | Source: /work/php-src/ext/openssl/openssl.c:2791 | Return: 0
• Function: PEM_write_bio_X509 | Source: /work/php-src/ext/openssl/openssl.c:3443 | Return: 0
• Function: PEM_write_bio_PrivateKey | Source: /work/php-src/ext/openssl/openssl.c:1520 | Return: 0
• Function: PEM_ASN1_read_bio | Source: /work/php-src/ext/openssl/openssl_backend_v3.c:871 | Return: 0
• Function: BIO_new | Source: /work/php-src/ext/openssl/openssl.c:1507 | Return: 0

PHP Version

Report was made on master, but applies to all versions really.

Operating System

No response

Start by reviewing error paths in ext/openssl/openssl_backend_common.c and ext/openssl/openssl.c, especially the cited calls to php_openssl_store_errors(), php_openssl_conf_get_string(), and OpenSSL I/O functions. Compare the listed inconsistencies and establish a consistent policy for return values, warnings, stored errors, and E_ERROR handling. Done means the extension has an agreed design and the affected call sites consistently follow it, with coverage for the changed behavior.