From eb1ef44efac797b384d361a76e33f77027c29a14 Mon Sep 17 00:00:00 2001 From: Hyunwoo Kim Date: Fri, 14 Apr 2023 13:11:59 +0300 Subject: [PATCH] wifi: iwlwifi: pcie: Fix integer overflow in iwl_write_to_user_buf [ Upstream commit 58d1b717879bfeabe09b35e41ad667c79933eb2e ] 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 Signed-off-by: Gregory Greenman Link: https://lore.kernel.org/r/20230414130637.2d80ace81532.Iecfba549e0e0be21bbb0324675392e42e75bd5ad@changeid Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- 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 54f11f60f11c4..8e95225cdd605 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c @@ -2852,7 +2852,7 @@ 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)