2021-06-17 02:20:05

by Kees Cook

Subject: [PATCH] orinoco: Avoid field-overflowing memcpy()

In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring array fields.

Validate the expected key size and introduce a wrapping structure
to use as the multi-field memcpy() destination so that overflows
can be correctly detected.

Signed-off-by: Kees Cook <[email protected]>
---
drivers/net/wireless/intersil/orinoco/hw.c | 18 +++++++++++-------
drivers/net/wireless/intersil/orinoco/hw.h | 5 +++--
drivers/net/wireless/intersil/orinoco/wext.c | 2 +-
3 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/intersil/orinoco/hw.c b/drivers/net/wireless/intersil/orinoco/hw.c
index 2c7adb4be100..0aea35c9c11c 100644
--- a/drivers/net/wireless/intersil/orinoco/hw.c
+++ b/drivers/net/wireless/intersil/orinoco/hw.c
@@ -988,15 +988,18 @@ int __orinoco_hw_setup_enc(struct orinoco_private *priv)
* tsc must be NULL or up to 8 bytes
*/
int __orinoco_hw_set_tkip_key(struct orinoco_private *priv, int key_idx,
- int set_tx, const u8 *key, const u8 *rsc,
- size_t rsc_len, const u8 *tsc, size_t tsc_len)
+ int set_tx, const u8 *key, size_t key_len,
+ const u8 *rsc, size_t rsc_len,
+ const u8 *tsc, size_t tsc_len)
{
struct {
__le16 idx;
u8 rsc[ORINOCO_SEQ_LEN];
- u8 key[TKIP_KEYLEN];
- u8 tx_mic[MIC_KEYLEN];
- u8 rx_mic[MIC_KEYLEN];
+ struct {
+ u8 key[TKIP_KEYLEN];
+ u8 tx_mic[MIC_KEYLEN];
+ u8 rx_mic[MIC_KEYLEN];
+ } tkip;
u8 tsc[ORINOCO_SEQ_LEN];
} __packed buf;
struct hermes *hw = &priv->hw;
@@ -1011,8 +1014,9 @@ int __orinoco_hw_set_tkip_key(struct orinoco_private *priv, int key_idx,
key_idx |= 0x8000;

buf.idx = cpu_to_le16(key_idx);
- memcpy(buf.key, key,
- sizeof(buf.key) + sizeof(buf.tx_mic) + sizeof(buf.rx_mic));
+ if (key_len != sizeof(buf.tkip))
+ return -EINVAL;
+ memcpy(&buf.tkip, key, sizeof(buf.tkip));

if (rsc_len > sizeof(buf.rsc))
rsc_len = sizeof(buf.rsc);
diff --git a/drivers/net/wireless/intersil/orinoco/hw.h b/drivers/net/wireless/intersil/orinoco/hw.h
index 466d1ede76f1..da5804dbdf34 100644
--- a/drivers/net/wireless/intersil/orinoco/hw.h
+++ b/drivers/net/wireless/intersil/orinoco/hw.h
@@ -38,8 +38,9 @@ int __orinoco_hw_set_wap(struct orinoco_private *priv);
int __orinoco_hw_setup_wepkeys(struct orinoco_private *priv);
int __orinoco_hw_setup_enc(struct orinoco_private *priv);
int __orinoco_hw_set_tkip_key(struct orinoco_private *priv, int key_idx,
- int set_tx, const u8 *key, const u8 *rsc,
- size_t rsc_len, const u8 *tsc, size_t tsc_len);
+ int set_tx, const u8 *key, size_t key_len,
+ const u8 *rsc, size_t rsc_len,
+ const u8 *tsc, size_t tsc_len);
int orinoco_clear_tkip_key(struct orinoco_private *priv, int key_idx);
int __orinoco_hw_set_multicast_list(struct orinoco_private *priv,
struct net_device *dev,
diff --git a/drivers/net/wireless/intersil/orinoco/wext.c b/drivers/net/wireless/intersil/orinoco/wext.c
index 7b6c4ae8ddb3..4a01260027bc 100644
--- a/drivers/net/wireless/intersil/orinoco/wext.c
+++ b/drivers/net/wireless/intersil/orinoco/wext.c
@@ -791,7 +791,7 @@ static int orinoco_ioctl_set_encodeext(struct net_device *dev,

err = __orinoco_hw_set_tkip_key(priv, idx,
ext->ext_flags & IW_ENCODE_EXT_SET_TX_KEY,
- priv->keys[idx].key,
+ priv->keys[idx].key, priv->keys[idx].key_len,
tkip_iv, ORINOCO_SEQ_LEN, NULL, 0);
if (err)
printk(KERN_ERR "%s: Error %d setting TKIP key"
--
2.25.1

2021-06-22 15:25:04

by Kalle Valo

Subject: Re: [PATCH] orinoco: Avoid field-overflowing memcpy()

Kees Cook <[email protected]> wrote:

> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field bounds checking for memcpy(), memmove(), and memset(), avoid
> intentionally writing across neighboring array fields.
>
> Validate the expected key size and introduce a wrapping structure
> to use as the multi-field memcpy() destination so that overflows
> can be correctly detected.
>
> Signed-off-by: Kees Cook <[email protected]>

Patch applied to wireless-drivers-next.git, thanks.

70ca8441ebfc orinoco: Avoid field-overflowing memcpy()

--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches