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Catch invalid typlens in a couple of places

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Rearrange the logic in record_image_cmp() and record_image_eq() to
error out on unexpected typlens (either not supported there or
completely invalid due to corruption).  Barring corruption, this is
not possible today but it seems more future-proof and robust to fix
this.

Reported-by: Peter Geoghegan <pg@bowt.ie>
This commit is contained in:
Peter Eisentraut 2019-11-04 09:54:47 +01:00
parent d43bd9dce8
commit 2dbe5706bb
1 changed files with 62 additions and 57 deletions
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119
src/backend/utils/adt/rowtypes.c
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@ -1426,30 +1426,7 @@ record_image_cmp(FunctionCallInfo fcinfo)
} }
/* Compare the pair of elements */ /* Compare the pair of elements */
if (tupdesc1->attrs[i1]->attlen == -1) if (tupdesc1->attrs[i1]->attbyval)
{
Size len1,
len2;
struct varlena *arg1val;
struct varlena *arg2val;
len1 = toast_raw_datum_size(values1[i1]);
len2 = toast_raw_datum_size(values2[i2]);
arg1val = PG_DETOAST_DATUM_PACKED(values1[i1]);
arg2val = PG_DETOAST_DATUM_PACKED(values2[i2]);
cmpresult = memcmp(VARDATA_ANY(arg1val),
VARDATA_ANY(arg2val),
Min(len1, len2) - VARHDRSZ);
if ((cmpresult == 0) && (len1 != len2))
cmpresult = (len1 < len2) ? -1 : 1;
if ((Pointer) arg1val != (Pointer) values1[i1])
pfree(arg1val);
if ((Pointer) arg2val != (Pointer) values2[i2])
pfree(arg2val);
}
else if (tupdesc1->attrs[i1]->attbyval)
{ {
switch (tupdesc1->attrs[i1]->attlen) switch (tupdesc1->attrs[i1]->attlen)
{ {
@ -1491,12 +1468,37 @@ record_image_cmp(FunctionCallInfo fcinfo)
Assert(false); /* cannot happen */ Assert(false); /* cannot happen */
} }
} }
else else if (tupdesc1->attrs[i1]->attlen > 0)
{ {
cmpresult = memcmp(DatumGetPointer(values1[i1]), cmpresult = memcmp(DatumGetPointer(values1[i1]),
DatumGetPointer(values2[i2]), DatumGetPointer(values2[i2]),
tupdesc1->attrs[i1]->attlen); tupdesc1->attrs[i1]->attlen);
} }
else if (tupdesc1->attrs[i1]->attlen == -1)
{
Size len1,
len2;
struct varlena *arg1val;
struct varlena *arg2val;
len1 = toast_raw_datum_size(values1[i1]);
len2 = toast_raw_datum_size(values2[i2]);
arg1val = PG_DETOAST_DATUM_PACKED(values1[i1]);
arg2val = PG_DETOAST_DATUM_PACKED(values2[i2]);
cmpresult = memcmp(VARDATA_ANY(arg1val),
VARDATA_ANY(arg2val),
Min(len1, len2) - VARHDRSZ);
if ((cmpresult == 0) && (len1 != len2))
cmpresult = (len1 < len2) ? -1 : 1;
if ((Pointer) arg1val != (Pointer) values1[i1])
pfree(arg1val);
if ((Pointer) arg2val != (Pointer) values2[i2])
pfree(arg2val);
}
else
elog(ERROR, "unexpected attlen: %d", tupdesc1->attrs[i1]->attlen);
if (cmpresult < 0) if (cmpresult < 0)
{ {
@ -1687,7 +1689,39 @@ record_image_eq(PG_FUNCTION_ARGS)
} }
/* Compare the pair of elements */ /* Compare the pair of elements */
if (tupdesc1->attrs[i1]->attlen == -1) if (tupdesc1->attrs[i1]->attbyval)
{
switch (tupdesc1->attrs[i1]->attlen)
{
case 1:
result = (GET_1_BYTE(values1[i1]) ==
GET_1_BYTE(values2[i2]));
break;
case 2:
result = (GET_2_BYTES(values1[i1]) ==
GET_2_BYTES(values2[i2]));
break;
case 4:
result = (GET_4_BYTES(values1[i1]) ==
GET_4_BYTES(values2[i2]));
break;
#if SIZEOF_DATUM == 8
case 8:
result = (GET_8_BYTES(values1[i1]) ==
GET_8_BYTES(values2[i2]));
break;
#endif
default:
Assert(false); /* cannot happen */
}
}
else if (tupdesc1->attrs[i1]->attlen > 0)
{
result = (memcmp(DatumGetPointer(values1[i1]),
DatumGetPointer(values2[i2]),
tupdesc1->attrs[i1]->attlen) == 0);
}
else if (tupdesc1->attrs[i1]->attlen == -1)
{ {
Size len1, Size len1,
len2; len2;
@ -1716,38 +1750,9 @@ record_image_eq(PG_FUNCTION_ARGS)
pfree(arg2val); pfree(arg2val);
} }
} }
else if (tupdesc1->attrs[i1]->attbyval)
{
switch (tupdesc1->attrs[i1]->attlen)
{
case 1:
result = (GET_1_BYTE(values1[i1]) ==
GET_1_BYTE(values2[i2]));
break;
case 2:
result = (GET_2_BYTES(values1[i1]) ==
GET_2_BYTES(values2[i2]));
break;
case 4:
result = (GET_4_BYTES(values1[i1]) ==
GET_4_BYTES(values2[i2]));
break;
#if SIZEOF_DATUM == 8
case 8:
result = (GET_8_BYTES(values1[i1]) ==
GET_8_BYTES(values2[i2]));
break;
#endif
default:
Assert(false); /* cannot happen */
}
}
else else
{ elog(ERROR, "unexpected attlen: %d", tupdesc1->attrs[i1]->attlen);
result = (memcmp(DatumGetPointer(values1[i1]),
DatumGetPointer(values2[i2]),
tupdesc1->attrs[i1]->attlen) == 0);
}
if (!result) if (!result)
break; break;
} }