[PATCH v2] crypto: marvell/octeontx - prevent integer overflows

[PATCH v2] crypto: marvell/octeontx - prevent integer overflows

[Dan Carpenter]

The "code_length" value comes from the firmware file.  If your firmware
is untrusted realistically there is probably very little you can do to
protect yourself.  Still we try to limit the damage as much as possible.
Also Smatch marks any data read from the filesystem as untrusted and
prints warnings if it not capped correctly.

The "code_length * 2" can overflow.  The round_up(ucode_size, 16) +
sizeof() expression can overflow too.  Prevent these overflows.

Fixes: d9110b0b01ff ("crypto: marvell - add support for OCTEON TX CPT engine")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: In the first commit, I accidentally added some unnecessary checks.
    Those were only drafts and I sent them uninitentionally.  Sorry!

 .../crypto/marvell/octeontx/otx_cptpf_ucode.c  | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/marvell/octeontx/otx_cptpf_ucode.c b/drivers/crypto/marvell/octeontx/otx_cptpf_ucode.c
index 23c6edc70914..df9c2b8747e6 100644
--- a/drivers/crypto/marvell/octeontx/otx_cptpf_ucode.c
+++ b/drivers/crypto/marvell/octeontx/otx_cptpf_ucode.c
@@ -286,6 +286,7 @@ static int process_tar_file(struct device *dev,
 	struct tar_ucode_info_t *tar_info;
 	struct otx_cpt_ucode_hdr *ucode_hdr;
 	int ucode_type, ucode_size;
+	unsigned int code_length;
 
 	/*
 	 * If size is less than microcode header size then don't report
@@ -303,7 +304,13 @@ static int process_tar_file(struct device *dev,
 	if (get_ucode_type(ucode_hdr, &ucode_type))
 		return 0;
 
-	ucode_size = ntohl(ucode_hdr->code_length) * 2;
+	code_length = ntohl(ucode_hdr->code_length);
+	if (code_length >= INT_MAX / 2) {
+		dev_err(dev, "Invalid code_length %u\n", code_length);
+		return -EINVAL;
+	}
+
+	ucode_size = code_length * 2;
 	if (!ucode_size || (size < round_up(ucode_size, 16) +
 	    sizeof(struct otx_cpt_ucode_hdr) + OTX_CPT_UCODE_SIGN_LEN)) {
 		dev_err(dev, "Ucode %s invalid size\n", filename);
@@ -886,6 +893,7 @@ static int ucode_load(struct device *dev, struct otx_cpt_ucode *ucode,
 {
 	struct otx_cpt_ucode_hdr *ucode_hdr;
 	const struct firmware *fw;
+	unsigned int code_length;
 	int ret;
 
 	set_ucode_filename(ucode, ucode_filename);
@@ -896,7 +904,13 @@ static int ucode_load(struct device *dev, struct otx_cpt_ucode *ucode,
 	ucode_hdr = (struct otx_cpt_ucode_hdr *) fw->data;
 	memcpy(ucode->ver_str, ucode_hdr->ver_str, OTX_CPT_UCODE_VER_STR_SZ);
 	ucode->ver_num = ucode_hdr->ver_num;
-	ucode->size = ntohl(ucode_hdr->code_length) * 2;
+	code_length = ntohl(ucode_hdr->code_length);
+	if (code_length >= INT_MAX / 2) {
+		dev_err(dev, "Ucode invalid code_length %u\n", code_length);
+		ret = -EINVAL;
+		goto release_fw;
+	}
+	ucode->size = code_length * 2;
 	if (!ucode->size || (fw->size < round_up(ucode->size, 16)
 	    + sizeof(struct otx_cpt_ucode_hdr) + OTX_CPT_UCODE_SIGN_LEN)) {
 		dev_err(dev, "Ucode %s invalid size\n", ucode_filename);
-- 
2.35.1

Re: [PATCH v2] crypto: marvell/octeontx - prevent integer overflows

[Herbert Xu]

On Mon, Sep 19, 2022 at 09:43:19AM +0300, Dan Carpenter wrote:
> The "code_length" value comes from the firmware file.  If your firmware
> is untrusted realistically there is probably very little you can do to
> protect yourself.  Still we try to limit the damage as much as possible.
> Also Smatch marks any data read from the filesystem as untrusted and
> prints warnings if it not capped correctly.
> 
> The "code_length * 2" can overflow.  The round_up(ucode_size, 16) +
> sizeof() expression can overflow too.  Prevent these overflows.
> 
> Fixes: d9110b0b01ff ("crypto: marvell - add support for OCTEON TX CPT engine")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> v2: In the first commit, I accidentally added some unnecessary checks.
>     Those were only drafts and I sent them uninitentionally.  Sorry!
> 
>  .../crypto/marvell/octeontx/otx_cptpf_ucode.c  | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt