AVRO-4344: [C] Reject out-of-range enum ordinal instead of returning an uninitialized pointer - #3948
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iemejia wants to merge 1 commit into
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AVRO-4344: [C] Reject out-of-range enum ordinal instead of returning an uninitialized pointer#3948iemejia wants to merge 1 commit into
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…an uninitialized pointer avro_schema_enum_get() called st_lookup() but ignored its return value, so for an index outside the schema's symbol range it returned an uninitialized stack value as a char *. The binary reader also passed the enum ordinal read from the input straight through without a range check, so a malformed or truncated container file could drive that path and a caller using the returned symbol name (e.g. avropipe calling strlen) would read through an indeterminate pointer and typically crash. - value-read.c: validate the decoded enum ordinal against the number of symbols and return EINVAL for an out-of-range value. - schema.c: avro_schema_enum_get() now returns NULL when st_lookup() fails. Adds test_avro_4344 covering a valid ordinal, an out-of-range positive ordinal, a negative ordinal, and avro_schema_enum_get() returning NULL. Reported by Mahdi Alhakim.
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What
avro_schema_enum_get()(lang/c/src/schema.c) calledst_lookup()but ignored its return value:For an index outside the schema's symbol range,
st_lookup()leavesval.datauntouched, so the function returned an uninitialized stack value as achar *.The binary reader (
lang/c/src/value-read.c,AVRO_ENUMcase) also passed the enum ordinal read from the input straight through without a range check, so a malformed or truncated container file could drive that path. A caller that then uses the returned symbol name (e.g.avropipecallingstrlen()) reads through an indeterminate pointer and typically crashes withSIGSEGVon a defaultReleasebuild.Fix
avro_schema_enum_number_of_symbols()and returnEINVALfor an out-of-range value.avro_schema_enum_get()returnsNULLwhenst_lookup()fails, so it can never return an uninitialized pointer even if called directly.Tests
Adds
test_avro_4344(self-contained, no data file): a valid ordinal reads successfully; an out-of-range positive ordinal, a negative ordinal, andavro_schema_enum_get(schema, 99)are all handled cleanly (error /NULL). Verified the test fails without the fix and passes with it; the fulllang/csuite (28 tests) passes.JIRA: https://issues.apache.org/jira/browse/AVRO-4344
Reported by Mahdi Alhakim.