Add zend.dlopen_deepbind php.ini directive #11094
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Add a runtime configuration option to control whether loading shared libraries via dlopen(3) uses the GNU extension flag RTLD_DEEPBIND, if available. The flag ensures symbol lookup will prefer symbols from the shared object itself over global ones, which can resolve symbol namespace collisions in third party dependencies, see 601140c ("New versions of glibc support a RTLD_DEEPBIND flag to dlopen. The"). However using this flag symbols from preloaded libraries might be de- prioritized, e.g. free(3) from a preloaded allocator by the standard libc. This results in one allocator allocating memory and another one deallocating it, triggering double/invalid-free assertions. Closes: php#10670
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I'm not sure why we needed I would try to remove it completely. |
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The reason was explained by Joe here: #10670 (comment) |
I see. We might keep May be we should use |
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I just afraid of this new option in user hands. |
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The issue for me with a configure option is that distributions probably are not (or only very inert) going to adapt it. And the difference between rebuilding php to specify an additional configure option or apply a curom patch is rather cosmetic. |
Add a runtime configuration option to control whether loading shared libraries via dlopen(3) uses the GNU extension flag RTLD_DEEPBIND, if available.
The flag ensures symbol lookup will prefer symbols from the shared object itself over global ones, which can resolve symbol namespace collisions in third party dependencies, see 601140c ("New versions of glibc support a RTLD_DEEPBIND flag to dlopen. The").
However using this flag symbols from preloaded libraries might be de- prioritized, e.g. free(3) from a preloaded allocator by the standard libc. This results in one allocator allocating memory and another one deallocating it, triggering double/invalid-free assertions.
Closes: #10670