[PATCH] hostap: avoid uninitialized variable use in hfa384x_get_rid

From: Arnd Bergmann
Date: Wed Jan 27 2016 - 08:46:24 EST


The driver reads a value from hfa384x_from_bap(), which may fail,
and then assigns the value to a local variable. gcc detects that
in in the failure case, the 'rlen' variable now contains
uninitialized data:

In file included from ../drivers/net/wireless/intersil/hostap/hostap_pci.c:220:0:
drivers/net/wireless/intersil/hostap/hostap_hw.c: In function 'hfa384x_get_rid':
drivers/net/wireless/intersil/hostap/hostap_hw.c:842:5: warning: 'rec' may be used uninitialized in this function [-Wmaybe-uninitialized]
if (le16_to_cpu(rec.len) == 0) {

To ensure we get consistent error handling here, this changes the code
to only set rlen if we actually read data correctly, which also takes
care of the warning.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/net/wireless/intersil/hostap/hostap_hw.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/intersil/hostap/hostap_hw.c b/drivers/net/wireless/intersil/hostap/hostap_hw.c
index 6df3ee561d52..6dbf8ee9490a 100644
--- a/drivers/net/wireless/intersil/hostap/hostap_hw.c
+++ b/drivers/net/wireless/intersil/hostap/hostap_hw.c
@@ -839,12 +839,15 @@ static int hfa384x_get_rid(struct net_device *dev, u16 rid, void *buf, int len,
if (!res)
res = hfa384x_from_bap(dev, BAP0, &rec, sizeof(rec));

- if (le16_to_cpu(rec.len) == 0) {
- /* RID not available */
- res = -ENODATA;
+ if (!res) {
+ if (le16_to_cpu(rec.len) == 0) {
+ /* RID not available */
+ res = -ENODATA;
+ }
+
+ rlen = (le16_to_cpu(rec.len) - 1) * 2;
}

- rlen = (le16_to_cpu(rec.len) - 1) * 2;
if (!res && exact_len && rlen != len) {
printk(KERN_DEBUG "%s: hfa384x_get_rid - RID len mismatch: "
"rid=0x%04x, len=%d (expected %d)\n",
--
2.7.0