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authorKjell Winblad <[email protected]>2019-01-29 12:33:19 +0100
committerKjell Winblad <[email protected]>2019-01-30 14:38:25 +0100
commit1df3d85824601e3c07d12ca9811866c2ef334e76 (patch)
treee6de0e195b436e69aee3af23ec6a890d43636ab4 /erts/emulator
parent71e7b98034ac00d9ee5428ed0602646e29851a29 (diff)
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Fix bug in binary:encode_unsigned causing a read of uninitialized memory
The bug could be seen by running the test that is added by this commit in a valgrind enabled emulator. Co-authored-by: John Högberg <[email protected]>
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/beam/erl_bif_binary.c18
1 files changed, 7 insertions, 11 deletions
diff --git a/erts/emulator/beam/erl_bif_binary.c b/erts/emulator/beam/erl_bif_binary.c
index a2610bf2e1..ae1bf6e652 100644
--- a/erts/emulator/beam/erl_bif_binary.c
+++ b/erts/emulator/beam/erl_bif_binary.c
@@ -2762,7 +2762,7 @@ static BIF_RETTYPE do_encode_unsigned(Process *p, Eterm uns, Eterm endianess)
dsize_t num_parts = BIG_SIZE(bigp);
Eterm res;
byte *b;
- ErtsDigit d;
+ ErtsDigit d = 0;
if(BIG_SIGN(bigp)) {
goto badarg;
@@ -2778,26 +2778,22 @@ static BIF_RETTYPE do_encode_unsigned(Process *p, Eterm uns, Eterm endianess)
if (endianess == am_big) {
Sint i,j;
j = 0;
- d = BIG_DIGIT(bigp,0);
for (i=n-1;i>=0;--i) {
- b[i] = d & 0xFF;
- if (!((++j) % sizeof(ErtsDigit))) {
+ if (!((j++) % sizeof(ErtsDigit))) {
d = BIG_DIGIT(bigp,j / sizeof(ErtsDigit));
- } else {
- d >>= 8;
}
+ b[i] = d & 0xFF;
+ d >>= 8;
}
} else {
Sint i,j;
j = 0;
- d = BIG_DIGIT(bigp,0);
for (i=0;i<n;++i) {
- b[i] = d & 0xFF;
- if (!((++j) % sizeof(ErtsDigit))) {
+ if (!((j++) % sizeof(ErtsDigit))) {
d = BIG_DIGIT(bigp,j / sizeof(ErtsDigit));
- } else {
- d >>= 8;
}
+ b[i] = d & 0xFF;
+ d >>= 8;
}
}