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authorBjörn Gustavsson <[email protected]>2011-05-10 10:56:24 +0200
committerBjörn Gustavsson <[email protected]>2011-08-03 11:24:52 +0200
commite8becad96454a8deb755f587ca0daaf96dfca90e (patch)
tree40ba945786f497611441f5a13f07efdf2e210879
parent07936436b8a8b18b80451a09e040283ebecbd43b (diff)
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Fix construction of <<0:((1 bsl 32)-1)>>
Attempting to construct <<0:((1 bsl 32)-1)>>, the largest bitstring allowed in a 32 bit emulator, would cause an emulator crash because of integer overflow. Fix the problem by using an Uint64 to avoid integer overflow. Do not attempt to handle construction of <<0:((1 bsl 64)-1>> in a 64-bit emulator, because that will certainly cause the emulator to terminate anyway because of insufficient memory.
-rw-r--r--erts/emulator/beam/beam_emu.c2
-rw-r--r--erts/emulator/beam/erl_bits.h2
-rw-r--r--erts/emulator/test/bs_construct_SUITE.erl5
3 files changed, 7 insertions, 2 deletions
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index fb90a7d4f7..937b3d9e53 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -3561,7 +3561,7 @@ void process_main(void)
* Operands: NotUsed Live Dst
*/
do_bs_init_bits_known:
- num_bytes = (num_bits+7) >> 3;
+ num_bytes = ((Uint64)num_bits+(Uint64)7) >> 3;
if (num_bits & 7) {
alloc += ERL_SUB_BIN_SIZE;
}
diff --git a/erts/emulator/beam/erl_bits.h b/erts/emulator/beam/erl_bits.h
index 0f67733fa4..3309ea706b 100644
--- a/erts/emulator/beam/erl_bits.h
+++ b/erts/emulator/beam/erl_bits.h
@@ -150,7 +150,7 @@ void erts_bits_destroy_state(ERL_BITS_PROTO_0);
* NBYTES(x) returns the number of bytes needed to store x bits.
*/
-#define NBYTES(x) (((x) + 7) >> 3)
+#define NBYTES(x) (((Uint64)(x) + (Uint64) 7) >> 3)
#define BYTE_OFFSET(ofs) ((Uint) (ofs) >> 3)
#define BIT_OFFSET(ofs) ((ofs) & 7)
diff --git a/erts/emulator/test/bs_construct_SUITE.erl b/erts/emulator/test/bs_construct_SUITE.erl
index 1959803385..ef5940d748 100644
--- a/erts/emulator/test/bs_construct_SUITE.erl
+++ b/erts/emulator/test/bs_construct_SUITE.erl
@@ -553,6 +553,11 @@ huge_float_check({'EXIT',{badarg,_}}) -> ok.
huge_binary(Config) when is_list(Config) ->
?line 16777216 = size(<<0:(id(1 bsl 26)),(-1):(id(1 bsl 26))>>),
+ ?line garbage_collect(),
+ ?line id(<<0:((1 bsl 32)-1)>>),
+ ?line garbage_collect(),
+ ?line id(<<0:(id((1 bsl 32)-1))>>),
+ ?line garbage_collect(),
ok.
system_limit(Config) when is_list(Config) ->