From: Eric Biggers <ebiggers@xxxxxxxxxx> commit c51abd96837f600d8fd940b6ab8e2da578575504 upstream. In many cases, keyctl_pkey_params_get_2() is validating the user buffer lengths against the wrong algorithm properties. Fix it to check against the correct properties. Probably this wasn't noticed before because for all asymmetric keys of the "public_key" subtype, max_data_size == max_sig_size == max_enc_size == max_dec_size. However, this isn't necessarily true for the "asym_tpm" subtype (it should be, but it's not strictly validated). Of course, future key types could have different values as well. Fixes: 00d60fd3b932 ("KEYS: Provide keyctls to drive the new key type ops for asymmetric keys [ver #2]") Cc: <stable@xxxxxxxxxxxxxxx> # v4.20+ Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> Reviewed-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- security/keys/keyctl_pkey.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) --- a/security/keys/keyctl_pkey.c +++ b/security/keys/keyctl_pkey.c @@ -135,15 +135,23 @@ static int keyctl_pkey_params_get_2(cons switch (op) { case KEYCTL_PKEY_ENCRYPT: + if (uparams.in_len > info.max_dec_size || + uparams.out_len > info.max_enc_size) + return -EINVAL; + break; case KEYCTL_PKEY_DECRYPT: if (uparams.in_len > info.max_enc_size || uparams.out_len > info.max_dec_size) return -EINVAL; break; case KEYCTL_PKEY_SIGN: + if (uparams.in_len > info.max_data_size || + uparams.out_len > info.max_sig_size) + return -EINVAL; + break; case KEYCTL_PKEY_VERIFY: - if (uparams.in_len > info.max_sig_size || - uparams.out_len > info.max_data_size) + if (uparams.in_len > info.max_data_size || + uparams.in2_len > info.max_sig_size) return -EINVAL; break; default: @@ -151,7 +159,7 @@ static int keyctl_pkey_params_get_2(cons } params->in_len = uparams.in_len; - params->out_len = uparams.out_len; + params->out_len = uparams.out_len; /* Note: same as in2_len */ return 0; } Patches currently in stable-queue which might be from ebiggers@xxxxxxxxxx are queue-5.4/keys-fix-length-validation-in-keyctl_pkey_params_get_2.patch