crypto: cavium - prevent integer overflow loading firmware

[ Upstream commit 2526d6bf27d15054bb0778b2f7bc6625fd934905 ]

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 "ntohl(ucode->code_length) * 2" multiplication can have an
integer overflow.

Fixes: 9e2c7d99941d ("crypto: cavium - Add Support for Octeon-tx CPT Engine")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/crypto/cavium/cpt/cptpf_main.c b/drivers/crypto/cavium/cpt/cptpf_main.c
index 34a6d8bf229ef31cf5fbbb200d11c5558745a3c0..dc34326e80df9f45db9983ae6792503748fd1d10 100644 (file)
--- a/drivers/crypto/cavium/cpt/cptpf_main.c
+++ b/drivers/crypto/cavium/cpt/cptpf_main.c
@@ -257,6 +257,7 @@ static int cpt_ucode_load_fw(struct cpt_device *cpt, const u8 *fw, bool is_ae)
        const struct firmware *fw_entry;
        struct device *dev = &cpt->pdev->dev;
        struct ucode_header *ucode;
+       unsigned int code_length;
        struct microcode *mcode;
        int j, ret = 0;
 
@@ -267,11 +268,12 @@ static int cpt_ucode_load_fw(struct cpt_device *cpt, const u8 *fw, bool is_ae)
        ucode = (struct ucode_header *)fw_entry->data;
        mcode = &cpt->mcode[cpt->next_mc_idx];
        memcpy(mcode->version, (u8 *)fw_entry->data, CPT_UCODE_VERSION_SZ);
-       mcode->code_size = ntohl(ucode->code_length) * 2;
-       if (!mcode->code_size) {
+       code_length = ntohl(ucode->code_length);
+       if (code_length == 0 || code_length >= INT_MAX / 2) {
                ret = -EINVAL;
                goto fw_release;
        }
+       mcode->code_size = code_length * 2;
 
        mcode->is_ae = is_ae;
        mcode->core_mask = 0ULL;