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authorJohannes Berg <johannes@sipsolutions.net>2008-02-29 23:28:25 +0100
committerJohn W. Linville <linville@tuxdriver.com>2008-03-04 18:36:36 -0500
commitc2f2d3a06f8b628d444cf4f396d6c6ddd47e1d1f (patch)
tree7879c02aa491f6e335dd907b1093941bfb892215
parent8c28293f5514f64ba064bac7946aebeda4a663c6 (diff)
p54: fix eeprom parser length sanity checks
When I called p54_parse_eeprom() on a hand-coded structure I managed to make a small mistake with wrap->len which caused a segfault a few lines down when trying to read entry->len. This patch changes the validation code to avoid such problems. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Tested-by: Florian Fainelli <florian.fainelli@telecomint.eu> Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--drivers/net/wireless/p54common.c18
1 files changed, 11 insertions, 7 deletions
diff --git a/drivers/net/wireless/p54common.c b/drivers/net/wireless/p54common.c
index 56aabec73c2..d191e055a78 100644
--- a/drivers/net/wireless/p54common.c
+++ b/drivers/net/wireless/p54common.c
@@ -166,18 +166,23 @@ int p54_parse_eeprom(struct ieee80211_hw *dev, void *eeprom, int len)
struct p54_common *priv = dev->priv;
struct eeprom_pda_wrap *wrap = NULL;
struct pda_entry *entry;
- int i = 0;
unsigned int data_len, entry_len;
void *tmp;
int err;
+ u8 *end = (u8 *)eeprom + len;
wrap = (struct eeprom_pda_wrap *) eeprom;
entry = (void *)wrap->data + le16_to_cpu(wrap->len);
- i += 2;
- i += le16_to_cpu(entry->len)*2;
- while (i < len) {
+
+ /* verify that at least the entry length/code fits */
+ while ((u8 *)entry <= end - sizeof(*entry)) {
entry_len = le16_to_cpu(entry->len);
data_len = ((entry_len - 1) << 1);
+
+ /* abort if entry exceeds whole structure */
+ if ((u8 *)entry + sizeof(*entry) + data_len > end)
+ break;
+
switch (le16_to_cpu(entry->code)) {
case PDR_MAC_ADDRESS:
SET_IEEE80211_PERM_ADDR(dev, entry->data);
@@ -249,13 +254,12 @@ int p54_parse_eeprom(struct ieee80211_hw *dev, void *eeprom, int len)
priv->version = *(u8 *)(entry->data + 1);
break;
case PDR_END:
- i = len;
+ /* make it overrun */
+ entry_len = len;
break;
}
entry = (void *)entry + (entry_len + 1)*2;
- i += 2;
- i += entry_len*2;
}
if (!priv->iq_autocal || !priv->output_limit || !priv->curve_data) {