Bugfix/crash in ares sortaddrinfo#400
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bradh352 merged 2 commits intoMar 5, 2021
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The bug was generated because there was not check for the number of items in the list and invalid memory was accesed when the list was empty. There is a check for null after calling malloc but on some systems it always returns a valid address for size equals 0. For e.g., on macOS and Windows systems malloc returns a valid address: https://man.openbsd.org/malloc.3 https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/malloc However, on Linux malloc returns NULL if size equals 0: https://man7.org/linux/man-pages/man3/malloc.3.html Also, the openBSD manual says it more clearly: If nmemb or size is equal to 0, a unique pointer to an access protected, zero sized object is returned. Access via this pointer will generate a SIGSEGV exception. Relates To: c-ares#392, 0903dce
sergepetrenko
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Jul 29, 2022
The bug was generated because there was no check for the number of items in the list and invalid memory was accesed when the list was empty. There is a check for null after calling malloc but on some systems it always returns a valid address for size equals 0. Relates To: c-ares#392, 0903dce Fix By: @catalinh-bd
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The patch set contains the following:
ares__sortaddrinfowhen sending an empty list