wifi: iwlwifi: pcie: Fix integer overflow in iwl_write_to_user_buf
authorHyunwoo Kim <imv4bel@gmail.com>
Fri, 14 Apr 2023 10:11:59 +0000 (13:11 +0300)
committerJohannes Berg <johannes.berg@intel.com>
Fri, 14 Apr 2023 11:15:27 +0000 (13:15 +0200)
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@gmail.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230414130637.2d80ace81532.Iecfba549e0e0be21bbb0324675392e42e75bd5ad@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
drivers/net/wireless/intel/iwlwifi/pcie/trans.c

index 40283fe..1b32a40 100644 (file)
@@ -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)