2019-10-01 12:10:52

by Denis Efremov (Oracle)

Subject: [PATCH] wil6210: check len before memcpy() calls

memcpy() in wmi_set_ie() and wmi_update_ft_ies() is called with
src == NULL and len == 0. This is an undefined behavior. Fix it
by checking "ie_len > 0" before the memcpy() calls.

As suggested by GCC documentation:
"The pointers passed to memmove (and similar functions in <string.h>)
must be non-null even when nbytes==0, so GCC can use that information
to remove the check after the memmove call." [1]

[1] https://gcc.gnu.org/gcc-4.9/porting_to.html

Cc: Maya Erez <[email protected]>
Cc: Kalle Valo <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: [email protected]
Signed-off-by: Denis Efremov <[email protected]>
---
drivers/net/wireless/ath/wil6210/wmi.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/wil6210/wmi.c b/drivers/net/wireless/ath/wil6210/wmi.c
index 153b84447e40..41389c1eb252 100644
--- a/drivers/net/wireless/ath/wil6210/wmi.c
+++ b/drivers/net/wireless/ath/wil6210/wmi.c
@@ -2505,7 +2505,8 @@ int wmi_set_ie(struct wil6210_vif *vif, u8 type, u16 ie_len, const void *ie)
cmd->mgmt_frm_type = type;
/* BUG: FW API define ieLen as u8. Will fix FW */
cmd->ie_len = cpu_to_le16(ie_len);
- memcpy(cmd->ie_info, ie, ie_len);
+ if (ie_len)
+ memcpy(cmd->ie_info, ie, ie_len);
rc = wmi_send(wil, WMI_SET_APPIE_CMDID, vif->mid, cmd, len);
kfree(cmd);
out:
@@ -2541,7 +2542,8 @@ int wmi_update_ft_ies(struct wil6210_vif *vif, u16 ie_len, const void *ie)
}

cmd->ie_len = cpu_to_le16(ie_len);
- memcpy(cmd->ie_info, ie, ie_len);
+ if (ie_len)
+ memcpy(cmd->ie_info, ie, ie_len);
rc = wmi_send(wil, WMI_UPDATE_FT_IES_CMDID, vif->mid, cmd, len);
kfree(cmd);

--
2.21.0

2019-10-02 17:24:54

by Kalle Valo

Subject: Re: [PATCH] wil6210: check len before memcpy() calls

Denis Efremov <[email protected]> wrote:

> memcpy() in wmi_set_ie() and wmi_update_ft_ies() is called with
> src == NULL and len == 0. This is an undefined behavior. Fix it
> by checking "ie_len > 0" before the memcpy() calls.
>
> As suggested by GCC documentation:
> "The pointers passed to memmove (and similar functions in <string.h>)
> must be non-null even when nbytes==0, so GCC can use that information
> to remove the check after the memmove call." [1]
>
> [1] https://gcc.gnu.org/gcc-4.9/porting_to.html
>
> Cc: Maya Erez <[email protected]>
> Cc: Kalle Valo <[email protected]>
> Cc: "David S. Miller" <[email protected]>
> Cc: [email protected]
> Signed-off-by: Denis Efremov <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>

Patch applied to ath-next branch of ath.git, thanks.

2c840676be8f wil6210: check len before memcpy() calls

--
https://patchwork.kernel.org/patch/11168621/

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