Fix uninitialized variable accesses in sockets/conversions #10966
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This was first pointed out in phpGH-10959. The from_zval_... functions don't always write to the pointer, in particular it is necessary to check for an error before using the value. Otherwise we can access an uninitialized value and that's UB (and dangerous). Note: this does *NOT* get rid of the compiler warning. Even though there is error checking now, the compiler isn't smart enough to figure out that the values can not be used uninitialized.
Girgias
approved these changes
Mar 29, 2023
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| if (UNEXPECTED(ctx->err.has_error)) { | ||
| return; | ||
| } | ||
| } else { | ||
| family = ctx->sock->type; |
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Would moving this to be an unconditional set prior to the if branch get rid of the compiler warning?
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Yes. However, then we unconditionally do a memory load in all cases. So I'd prefer to just write a dummy value in the non-else branch and commit that on its own to master (similar for the other warning). WDYT?
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This was first pointed out in GH-10959.
The from_zval_... functions don't always write to the pointer, in particular it is necessary to check for an error before using the value. Otherwise we can access an uninitialized value and that's UB (and dangerous).
Note: this does NOT get rid of the compiler warning. Even though there is error checking now, the compiler isn't smart enough to figure out that the values can not be used uninitialized.