From: Hyunwoo Kim <imv4bel@xxxxxxxxx>
An integer overflow occurs in the iwl_write_to_user_buf() function,
which is called by the iwl_dbgfs_monitor_data_read() function.
static bool iwl_write_to_user_buf(char __user *user_buf, ssize_t count,
void *buf, ssize_t *size,
ssize_t *bytes_copied)
{
int buf_size_left = count - *bytes_copied;
buf_size_left = buf_size_left - (buf_size_left % sizeof(u32));
if (*size > buf_size_left)
*size = buf_size_left;
If the user passes a SIZE_MAX value to the "ssize_t count" parameter,
the ssize_t count parameter is assigned to "int buf_size_left".
Then compare "*size" with "buf_size_left" . Here, "buf_size_left" is a
negative number, so "*size" is assigned "buf_size_left" and goes into
the third argument of the copy_to_user function, causing a heap overflow.
This is not a security vulnerability because iwl_dbgfs_monitor_data_read()
is a debugfs operation with 0400 privileges.
Signed-off-by: Hyunwoo Kim <imv4bel@xxxxxxxxx>
Signed-off-by: Gregory Greenman <gregory.greenman@xxxxxxxxx>
---
drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 40283fe622da..1b32a4035d88 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -2860,7 +2860,7 @@ static bool iwl_write_to_user_buf(char __user *user_buf, ssize_t count,
void *buf, ssize_t *size,
ssize_t *bytes_copied)
{
- int buf_size_left = count - *bytes_copied;
+ ssize_t buf_size_left = count - *bytes_copied;
buf_size_left = buf_size_left - (buf_size_left % sizeof(u32));
if (*size > buf_size_left)
--
2.38.1
