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Reserved values 28 through 30 and the unsupported indefinite-length encoding also fall through without assigning it. parse_resp_get_random() then uses the indeterminate value for bounds checking and as the byte count returned to the hwrng core. This can reject a valid short response or report an incorrect amount of entropy. Decode the complete inline-length range and reject unsupported values. Extended definite-length encodings retain their existing behavior, and the existing size and INT_MAX checks continue to bound the returned slice. This issue was found by a static analysis checker and confirmed by manual source review. Fixes: b9873755a6c8 ("misc: Add Nitro Secure Module driver") Assisted-by: unnamed:claude-opus-4.8 typestate Signed-off-by: Ruoyu Wang --- Changes in v2: - Add the Assisted-by tag. v1: https://lore.kernel.org/r/20260814134013.1386522-1-ruoyuw560@gmail.com/ --- drivers/misc/nsm.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/misc/nsm.c b/drivers/misc/nsm.c index ef7b3274234099..ad4723f4dc4527 100644 --- a/drivers/misc/nsm.c +++ b/drivers/misc/nsm.c @@ -117,7 +117,7 @@ static int cbor_object_get_array(u8 *cbor_object, size_= t cbor_object_size, u8 ** array_len_p =3D &cbor_object[1]; =20 switch (cbor_short_size) { - case CBOR_SHORT_SIZE_MAX_VALUE: /* short encoding */ + case 0 ... CBOR_SHORT_SIZE_MAX_VALUE: /* short encoding */ array_len =3D cbor_short_size; break; case CBOR_LONG_SIZE_U8: @@ -132,6 +132,8 @@ static int cbor_object_get_array(u8 *cbor_object, size_= t cbor_object_size, u8 ** case CBOR_LONG_SIZE_U64: array_len =3D be64_to_cpup((__be64 *)array_len_p); break; + default: + return -EFAULT; } =20 if (cbor_object_size < array_offset) --=20 2.51.0