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Commit 3b6ef633 authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
Browse files

cfg80211: fix cmp_ies 



When comparing two items by IE, the sort order
wasn't stable, which could lead to issues in the
rbtree. Make it stable by making a missing IE
sort before a present IE.

Also sort by length first if it differs and then
by contents.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 133a3ff2

net/wireless/scan.c

+8 −5
Original line number Diff line number Diff line
@@ -259,17 +259,20 @@ static int cmp_ies(u8 num, u8 *ies1, size_t len1, u8 *ies2, size_t len2) 
{

	const u8 *ie1 = cfg80211_find_ie(num, ies1, len1);

	const u8 *ie2 = cfg80211_find_ie(num, ies2, len2);

	int r;



	/* equal if both missing */

	if (!ie1 && !ie2)

		return 0;

	if (!ie1 || !ie2)

	/* sort missing IE before (left of) present IE */

	if (!ie1)

		return -1;

	if (!ie2)

		return 1;



	r = memcmp(ie1 + 2, ie2 + 2, min(ie1[1], ie2[1]));

	if (r == 0 && ie1[1] != ie2[1])

	/* sort by length first, then by contents */

	if (ie1[1] != ie2[1])

		return ie2[1] - ie1[1];

	return r;

	return memcmp(ie1 + 2, ie2 + 2, ie1[1]);

}



static bool is_bss(struct cfg80211_bss *a,