From 2526d6bf27d15054bb0778b2f7bc6625fd934905 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Mon, 19 Sep 2022 09:43:27 +0300
Subject: [PATCH] crypto: cavium - prevent integer overflow loading firmware
Git-commit: 2526d6bf27d15054bb0778b2f7bc6625fd934905
Patch-mainline: v6.1-rc1
References: git-fixes

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/crypto/cavium/cpt/cptpf_main.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/crypto/cavium/cpt/cptpf_main.c b/drivers/crypto/cavium/cpt/cptpf_main.c
index 8c32d0eb8fcf..6872ac344001 100644
--- a/drivers/crypto/cavium/cpt/cptpf_main.c
+++ b/drivers/crypto/cavium/cpt/cptpf_main.c
@@ -253,6 +253,7 @@ 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;
 
@@ -263,11 +264,12 @@ 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;
-- 
2.35.3