Re: [PATCH v2] KEYS: trusted: Fix memory leak in tpm2_key_encode()
From: Jarkko Sakkinen <jarkko@kernel.org>
Date: 2022-06-09 05:23:23
Also in:
keyrings, linux-integrity, lkml
On Wed, Jun 08, 2022 at 09:17:32PM +0800, Jianglei Nie wrote:
tpm2_key_encode() allocates a memory chunk from scratch with kmalloc(), but it is never freed, which leads to a memory leak. Free the memory chunk with kfree() in the return path. Signed-off-by: Jianglei Nie <redacted> ---
You should write down the changelog ere. No idea what changed from the previous version.
quoted hunk ↗ jump to hunk
security/keys/trusted-keys/trusted_tpm2.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-)diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 0165da386289..8b7ab22950d1 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c@@ -32,6 +32,7 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, struct trusted_key_options *options, u8 *src, u32 len) { + int err;
Declare as the last local variable (reverse christmas tree order). Also, I'd use "int ret" since in other functions that is used.
quoted hunk ↗ jump to hunk
const int SCRATCH_SIZE = PAGE_SIZE; u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL); u8 *work = scratch, *work1;@@ -57,8 +58,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, unsigned char bool[3], *w = bool; /* tag 0 is emptyAuth */ w = asn1_encode_boolean(w, w + sizeof(bool), true); - if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) - return PTR_ERR(w); + if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) { + err = PTR_ERR(w); + goto out; + } work = asn1_encode_tag(work, end_work, 0, bool, w - bool); }@@ -69,8 +72,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, * trigger, so if it does there's something nefarious going on */ if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE, - "BUG: scratch buffer is too small")) - return -EINVAL; + "BUG: scratch buffer is too small")) { + err = -EINVAL; + goto out; + } work = asn1_encode_integer(work, end_work, options->keyhandle); work = asn1_encode_octet_string(work, end_work, pub, pub_len);@@ -79,10 +84,16 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, work1 = payload->blob; work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob), scratch, work - scratch); - if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) - return PTR_ERR(work1); + if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) { + err = -EINVAL; + goto out;
Why you are changing the return value from PTR_ERR(work1 to -EINVAL?
+ } + kfree(scratch); return work1 - payload->blob; + +out:
Nit: err: It's only used for the error path.
+ return err;
}
struct tpm2_key_context {
--
2.25.1BR, Jarkko