From 34380bad4985bc827866129597e0bea940e076f4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Magnus=20L=C3=A5ng?= Date: Tue, 1 Dec 2015 15:24:25 +0000 Subject: hipe: Fix signed compares of unsigned sizes Also, some of the branches were testing sizes in bits against a constant ?MAX_BINSIZE, which was in bytes. The signed comparisons masked this mistake. These branches have been removed since all sizes in bits that fit in a machine word are valid binary sizes. Finally, a test that reproduces the issue was added to bs_construct, along with a test for one of the cases (bs_init<0>(...)) when the test against ?MAX_BINSIZE must be changed to unsigned rather than removed. --- lib/hipe/test/bs_SUITE_data/bs_construct.erl | 34 ++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) (limited to 'lib/hipe/test/bs_SUITE_data') diff --git a/lib/hipe/test/bs_SUITE_data/bs_construct.erl b/lib/hipe/test/bs_SUITE_data/bs_construct.erl index 7251cdce43..b9e7d93570 100644 --- a/lib/hipe/test/bs_SUITE_data/bs_construct.erl +++ b/lib/hipe/test/bs_SUITE_data/bs_construct.erl @@ -18,6 +18,7 @@ test() -> ok = bad_append(), ok = system_limit(), ok = bad_floats(), + ok = huge_binaries(), ok. %%-------------------------------------------------------------------- @@ -269,3 +270,36 @@ bad_floats() -> {'EXIT',{badarg,_}} = (catch <<3.14:(id((1 bsl 28) bor 32))/float>>), {'EXIT',{system_limit,_}} = (catch <<3.14:(id(1 bsl BitsPerWord))/float>>), ok. + +%%-------------------------------------------------------------------- +%% A bug in the implementation of binaries compared sizes in bits with sizes in +%% bytes, causing <<0:(id((1 bsl 31)-1))>> to fail to construct with +%% 'system_limit'. +%% <<0:(id((1 bsl 32)-1))>> was succeeding because the comparison was +%% (incorrectly) signed. + +huge_binaries() -> + AlmostIllegal = id(<<0:(id((1 bsl 32)-8))>>), + case erlang:system_info(wordsize) of + 4 -> huge_binaries_32(AlmostIllegal); + 8 -> ok + end, + garbage_collect(), + id(<<0:(id((1 bsl 31)-1))>>), + id(<<0:(id((1 bsl 30)-1))>>), + garbage_collect(), + ok. + +huge_binaries_32(AlmostIllegal) -> + %% Attempt construction of too large binary using bs_init/1 (which takes the + %% number of bytes as an argument, which should be compared to the maximum + %% size in bytes). + {'EXIT',{system_limit,_}} = (catch <<0:32,AlmostIllegal/binary>>), + %% Attempt construction of too large binary using bs_init/1 with a size in + %% bytes that has the msb set (and would be negative if it was signed). + {'EXIT',{system_limit,_}} = + (catch <<0:8, AlmostIllegal/binary, AlmostIllegal/binary, + AlmostIllegal/binary, AlmostIllegal/binary, + AlmostIllegal/binary, AlmostIllegal/binary, + AlmostIllegal/binary, AlmostIllegal/binary>>), + ok. -- cgit v1.2.3