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p54: fix eeprom parser length sanity checks

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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
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@@ -166,18 +166,23 @@ int p54_parse_eeprom(struct ieee80211_hw *dev, void *eeprom, int len)
struct p54_common *priv = dev->priv; struct p54_common *priv = dev->priv;
struct eeprom_pda_wrap *wrap = NULL; struct eeprom_pda_wrap *wrap = NULL;
struct pda_entry *entry; struct pda_entry *entry;
int i = 0;
unsigned int data_len, entry_len; unsigned int data_len, entry_len;
void *tmp; void *tmp;
int err; int err;
u8 *end = (u8 *)eeprom + len;
wrap = (struct eeprom_pda_wrap *) eeprom; wrap = (struct eeprom_pda_wrap *) eeprom;
entry = (void *)wrap->data + le16_to_cpu(wrap->len); entry = (void *)wrap->data + le16_to_cpu(wrap->len);
i += 2;
i += le16_to_cpu(entry->len)*2; /* verify that at least the entry length/code fits */
while (i < len) { while ((u8 *)entry <= end - sizeof(*entry)) {
entry_len = le16_to_cpu(entry->len); entry_len = le16_to_cpu(entry->len);
data_len = ((entry_len - 1) << 1); 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)) { switch (le16_to_cpu(entry->code)) {
case PDR_MAC_ADDRESS: case PDR_MAC_ADDRESS:
SET_IEEE80211_PERM_ADDR(dev, entry->data); 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); priv->version = *(u8 *)(entry->data + 1);
break; break;
case PDR_END: case PDR_END:
i = len; /* make it overrun */
entry_len = len;
break; break;
} }
entry = (void *)entry + (entry_len + 1)*2; entry = (void *)entry + (entry_len + 1)*2;
i += 2;
i += entry_len*2;
} }
if (!priv->iq_autocal || !priv->output_limit || !priv->curve_data) { if (!priv->iq_autocal || !priv->output_limit || !priv->curve_data) {