In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: pcie: Fix integer overflow in iwl_write_to_user_buf
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.