diff options
| author | Johannes Berg <johannes@sipsolutions.net> | 2008-02-29 23:28:25 +0100 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2008-03-04 18:36:36 -0500 |
| commit | c2f2d3a06f8b628d444cf4f396d6c6ddd47e1d1f (patch) | |
| tree | 7879c02aa491f6e335dd907b1093941bfb892215 | |
| parent | 8c28293f5514f64ba064bac7946aebeda4a663c6 (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.c | 18 |
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) { |