| From: | stephen@isc.org |
| Date: | Tue, 05 Dec 2017 17:59:12 +0000 |
| To: | bind9-public@isc.org |
| Subject: | Issues found building BIND with -fsanitize=undefined |
The following errors/warnings in BIND code were produced when running the tests with the code on "master" compiled with gcc using the -fsanitize=undefined option:
* rdata/generic/opt_41.c:195:2: runtime error: null pointer passed as argument 2, which is declared to never be null
* name.c:2053:3: runtime error: null pointer passed as argument 2, which is declared to never be null
* name.c:2545:2: runtime error: null pointer passed as argument 2, which is declared to never be null
* message.c:4404:4: runtime error: null pointer passed as argument 2, which is declared to never be null
All these of these seem to be related to memmove (the last via the macro ISC__BUFFER_PUTMEM); it is likely that although the second argument is null, the third argument is 0, which means that no action is taken. However, a similar construct back in 2014 caused problems on a new version of gcc because the compiler noted that a pointer was passed as a "not null" argument to a glib function and subsequently optimised away a check protecting the pointer being dereferenced if it was null. (#35968)
* random.c:143:45: runtime error: left shift of 1748803827 by 12 places cannot be represented in type 'int'
* inet_aton.c:177:20: runtime error: left shift of 192 by 24 places cannot be represented in type 'int'
Both these messages appeared a number of times (with different numbers).
* random_test.c:204:20: runtime error: shift exponent 32 is too large for 32-bit type 'unsigned int'
I've only seen this message once.