Subject: Coverity: iwl_mvm_sec_key_add(): Memory - corruptions

From: coverity-bot <[email-masked]>
Date: Fri, 18 Nov 2022 08:54:54 -0800

Hello!

This is an experimental semi-automated report about issues detected by
Coverity from a scan of next-20221118 as part of the linux-next scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified
lines of code (noted below) that were touched by commits:

  Thu Nov 10 13:26:51 2022 +0200
    5c75a208c244 ("wifi: iwlwifi: mvm: support new key API")

Coverity reported the following:

*** CID 1527370:  Memory - corruptions  (OVERRUN)
drivers/net/wireless/intel/iwlwifi/mvm/mld-key.c:123 in iwl_mvm_sec_key_add()
117
118     	if (WARN_ON(keyconf->keylen > sizeof(cmd.u.add.key)))
119     		return -EINVAL;
120
121     	if (keyconf->cipher == WLAN_CIPHER_SUITE_WEP40 ||
122     	    keyconf->cipher == WLAN_CIPHER_SUITE_WEP104)
vvv     CID 1527370:  Memory - corruptions  (OVERRUN)
vvv     Overrunning buffer pointed to by "cmd.u.add.key + 3" of 32 bytes by passing it to a function which accesses it at byte offset 34 using argument "keyconf->keylen" (which evaluates to 32). [Note: The source code implementation of the function has been overridden by a builtin model.]
123     		memcpy(cmd.u.add.key + IWL_SEC_WEP_KEY_OFFSET, keyconf->key,
124     		       keyconf->keylen);
125     	else
126     		memcpy(cmd.u.add.key, keyconf->key, keyconf->keylen);
127
128     	if (keyconf->cipher == WLAN_CIPHER_SUITE_TKIP) {

If this is a false positive, please let us know so we can mark it as
such, or teach the Coverity rules to be smarter. If not, please make
sure fixes get into linux-next. :) For patches fixing this, please
include these lines (but double-check the "Fixes" first):

Reported-by: coverity-bot <[email-masked]>
Addresses-Coverity-ID: 1527370 ("Memory - corruptions")
Fixes: 5c75a208c244 ("wifi: iwlwifi: mvm: support new key API")

keyconf->keylen is only bounds-checked against sizeof(cmd.u.add.key),
but the memcpy() is starting a write at key + 3.

Thanks for your attention!

-- 
Coverity-bot