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Doruk Tan Ozturk
7dc44840ca
KEYCTL_PKEY_VERIFY lets an unprivileged caller supply a zero-length digest (in_len == 0). keyctl_pkey_params_get_2() accepts the zero length and the request reaches pkcs1pad_verify(), where the empty digest is rejected but only after being passed through WARN_ON(!digest_size). The warning is therefore directly user-triggerable, and on kernels built with panic_on_warn=1 an unprivileged process can panic the machine -- a local denial of service. Reproduced as UID 65534 in a setuid sandbox. Keep rejecting the invalid request with -EINVAL, but do not emit a warning for the user-controlled length. Mainline does not contain this code path; commit1e562deace("crypto: rsassa-pkcs1 - Migrate to sig_alg backend") removed pkcs1pad_verify() in v6.13-rc1. This is a minimal fix for the affected stable branches. It applies as-is to 6.1.y, 6.6.y and 6.12.y (identical pkcs1pad_verify); the 5.10.y/5.15.y form is sent as a separate patch due to the older req->dst_len spelling. Found by 0sec automated security-research tooling (https://0sec.ai). Fixes:c7381b0128("crypto: akcipher - new verify API for public key algorithms") Cc: stable@vger.kernel.org Assisted-by: 0sec:multi-model Signed-off-by: Doruk Tan Ozturk <doruk@0sec.ai> Reviewed-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Sasha Levin <sashal@kernel.org>