From fe1c9a443e0d1e0af790883f091fb1c4f418bc8f Mon Sep 17 00:00:00 2001 From: Amitkumar Karwar Date: Tue, 22 Oct 2013 15:24:44 -0700 Subject: [PATCH] mwifiex: fix invalid memory access in mwifiex_get_power_level() With "while (length)" check we may end up in accessing invalid memory in last iteration. This patch makes sure that tlv length is not less than the length of structure mwifiex_power_group when min/max power is calculated. Reported-by: Dan Carpenter Signed-off-by: Amitkumar Karwar Signed-off-by: Bing Zhao Signed-off-by: John W. Linville --- drivers/net/wireless/mwifiex/sta_cmdresp.c | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/drivers/net/wireless/mwifiex/sta_cmdresp.c b/drivers/net/wireless/mwifiex/sta_cmdresp.c index bdf50fd..5edea4d 100644 --- a/drivers/net/wireless/mwifiex/sta_cmdresp.c +++ b/drivers/net/wireless/mwifiex/sta_cmdresp.c @@ -341,12 +341,16 @@ static int mwifiex_get_power_level(struct mwifiex_private *priv, void *data_buf) pg = (struct mwifiex_power_group *) ((u8 *) pg_tlv_hdr + sizeof(struct mwifiex_types_power_group)); length = le16_to_cpu(pg_tlv_hdr->length); - if (length > 0) { - max_power = pg->power_max; - min_power = pg->power_min; - length -= sizeof(struct mwifiex_power_group); - } - while (length) { + + /* At least one structure required to update power */ + if (length < sizeof(struct mwifiex_power_group)) + return 0; + + max_power = pg->power_max; + min_power = pg->power_min; + length -= sizeof(struct mwifiex_power_group); + + while (length >= sizeof(struct mwifiex_power_group)) { pg++; if (max_power < pg->power_max) max_power = pg->power_max; @@ -356,10 +360,8 @@ static int mwifiex_get_power_level(struct mwifiex_private *priv, void *data_buf) length -= sizeof(struct mwifiex_power_group); } - if (le16_to_cpu(pg_tlv_hdr->length) > 0) { - priv->min_tx_power_level = (u8) min_power; - priv->max_tx_power_level = (u8) max_power; - } + priv->min_tx_power_level = (u8) min_power; + priv->max_tx_power_level = (u8) max_power; return 0; } -- 2.7.4