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authorEmmanuel Grumbach <emmanuel.grumbach@intel.com>2017-01-07 19:57:46 +0200
committerLuca Coelho <luciano.coelho@intel.com>2017-02-08 17:54:20 +0200
commit1aa0ec5cdf60b23dfc152f0e9e205f58b0a546b2 (patch)
tree800e63cc1524c42c4fb53030afa4774f64451520 /drivers/net/wireless/intel
parent6eac0e817aee2518a96b5ce9d02b904e0667f370 (diff)
iwlwifi: dvm: don't call << operator with a negative value
In https://bugzilla.kernel.org/show_bug.cgi?id=177341 Bob reported a UBSAN WARNING on rs.c. Undefined behaviour in drivers/net/wireless/intel/iwlwifi/dvm/rs.c:746:18 This because i = index - 1; for (mask = (1 << i); i >= 0; i--, mask >>= 1) is unsafe: i could be negative and hence we can call << on a negative value. This bug doesn't have any real impact since the condition of the for loop will prevent any usage of mask. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=177341 Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Diffstat (limited to 'drivers/net/wireless/intel')
-rw-r--r--drivers/net/wireless/intel/iwlwifi/dvm/rs.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/rs.c b/drivers/net/wireless/intel/iwlwifi/dvm/rs.c
index 710dbbefd551..ff44ebc5829d 100644
--- a/drivers/net/wireless/intel/iwlwifi/dvm/rs.c
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/rs.c
@@ -740,7 +740,10 @@ static u16 rs_get_adjacent_rate(struct iwl_priv *priv, u8 index, u16 rate_mask,
/* Find the previous rate that is in the rate mask */
i = index - 1;
- for (mask = (1 << i); i >= 0; i--, mask >>= 1) {
+ if (i >= 0)
+ mask = BIT(i);
+
+ for (; i >= 0; i--, mask >>= 1) {
if (rate_mask & mask) {
low = i;
break;