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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>
This commit is contained in:
Johannes Berg 2008-02-29 23:28:25 +01:00 committed by John W. Linville
parent 8c28293f55
commit c2f2d3a06f
1 changed files with 11 additions and 7 deletions
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18
drivers/net/wireless/p54common.c
View File

@ -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) {