| Message ID | 20211130084304.72160-1-zhou1615@umn.edu |
|---|---|
| State | New |
| Headers | show |
| Series | ath11k: Fix a NULL pointer dereference in ath11k_mac_op_hw_scan() | expand |
On 11/30/2021 12:43 AM, Zhou Qingyang wrote: > In ath11k_mac_op_hw_scan(), the return value of kzalloc() is directly > used in memcpy(), which may lead to a NULL pointer dereference on > failure of kzalloc(). > > Fix this bug by adding a check of arg.extraie.ptr. > > This bug was found by a static analyzer. The analysis employs > differential checking to identify inconsistent security operations > (e.g., checks or kfrees) between two code paths and confirms that the > inconsistent operations are not recovered in the current function or > the callers, so they constitute bugs. > > Note that, as a bug found by static analysis, it can be a false > positive or hard to trigger. Multiple researchers have cross-reviewed > the bug. > > Builds with CONFIG_ATH11K=m show no new warnings, and our static > analyzer no longer warns about this code. > > Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices") > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu> > --- > drivers/net/wireless/ath/ath11k/mac.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c > index 1cc55602787b..095f1f9b7611 100644 > --- a/drivers/net/wireless/ath/ath11k/mac.c > +++ b/drivers/net/wireless/ath/ath11k/mac.c > @@ -3237,8 +3237,13 @@ static int ath11k_mac_op_hw_scan(struct ieee80211_hw *hw, > arg.scan_id = ATH11K_SCAN_ID; > > if (req->ie_len) { > - arg.extraie.len = req->ie_len; > arg.extraie.ptr = kzalloc(req->ie_len, GFP_KERNEL); Your patch looks good, but since you are touching this code IMO this should be changed to kmemdup() and we should remove the memcpy() below. > + if (!arg.extraie.ptr) { > + ret = -ENOMEM; > + goto exit; > + } > + > + arg.extraie.len = req->ie_len; > memcpy(arg.extraie.ptr, req->ie, req->ie_len); > } > >
diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c index 1cc55602787b..095f1f9b7611 100644 --- a/drivers/net/wireless/ath/ath11k/mac.c +++ b/drivers/net/wireless/ath/ath11k/mac.c @@ -3237,8 +3237,13 @@ static int ath11k_mac_op_hw_scan(struct ieee80211_hw *hw, arg.scan_id = ATH11K_SCAN_ID; if (req->ie_len) { - arg.extraie.len = req->ie_len; arg.extraie.ptr = kzalloc(req->ie_len, GFP_KERNEL); + if (!arg.extraie.ptr) { + ret = -ENOMEM; + goto exit; + } + + arg.extraie.len = req->ie_len; memcpy(arg.extraie.ptr, req->ie, req->ie_len); }
In ath11k_mac_op_hw_scan(), the return value of kzalloc() is directly used in memcpy(), which may lead to a NULL pointer dereference on failure of kzalloc(). Fix this bug by adding a check of arg.extraie.ptr. This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. Builds with CONFIG_ATH11K=m show no new warnings, and our static analyzer no longer warns about this code. Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices") Signed-off-by: Zhou Qingyang <zhou1615@umn.edu> --- drivers/net/wireless/ath/ath11k/mac.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)