From: Szymon Heidrich szymon.heidrich@gmail.com
[ Upstream commit b870e73a56c4cccbec33224233eaf295839f228c ]
Since resplen and respoffs are signed integers sufficiently large values of unsigned int len and offset members of RNDIS response will result in negative values of prior variables. This may be utilized to bypass implemented security checks to either extract memory contents by manipulating offset or overflow the data buffer via memcpy by manipulating both offset and len.
Additionally assure that sum of resplen and respoffs does not overflow so buffer boundaries are kept.
Fixes: 80f8c5b434f9 ("rndis_wlan: copy only useful data from rndis_command respond") Signed-off-by: Szymon Heidrich szymon.heidrich@gmail.com Reviewed-by: Alexander Duyck alexanderduyck@fb.com Signed-off-by: Kalle Valo kvalo@kernel.org Link: https://lore.kernel.org/r/20230111175031.7049-1-szymon.heidrich@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/rndis_wlan.c | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c index 75b5d545b49e..dc076d844868 100644 --- a/drivers/net/wireless/rndis_wlan.c +++ b/drivers/net/wireless/rndis_wlan.c @@ -694,8 +694,8 @@ static int rndis_query_oid(struct usbnet *dev, u32 oid, void *data, int *len) struct rndis_query *get; struct rndis_query_c *get_c; } u; - int ret, buflen; - int resplen, respoffs, copylen; + int ret; + size_t buflen, resplen, respoffs, copylen;
buflen = *len + sizeof(*u.get); if (buflen < CONTROL_BUFFER_SIZE) @@ -730,22 +730,15 @@ static int rndis_query_oid(struct usbnet *dev, u32 oid, void *data, int *len)
if (respoffs > buflen) { /* Device returned data offset outside buffer, error. */ - netdev_dbg(dev->net, "%s(%s): received invalid " - "data offset: %d > %d\n", __func__, - oid_to_string(oid), respoffs, buflen); + netdev_dbg(dev->net, + "%s(%s): received invalid data offset: %zu > %zu\n", + __func__, oid_to_string(oid), respoffs, buflen);
ret = -EINVAL; goto exit_unlock; }
- if ((resplen + respoffs) > buflen) { - /* Device would have returned more data if buffer would - * have been big enough. Copy just the bits that we got. - */ - copylen = buflen - respoffs; - } else { - copylen = resplen; - } + copylen = min(resplen, buflen - respoffs);
if (copylen > *len) copylen = *len;