From: Hyunwoo Kim imv4bel@gmail.com
[ 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 imv4bel@gmail.com Signed-off-by: Gregory Greenman gregory.greenman@intel.com Link: https://lore.kernel.org/r/20230414130637.2d80ace81532.Iecfba549e0e0be21bbb03... Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 ee325950de9d2..04e1f3829e96b 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c @@ -2778,7 +2778,7 @@ 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)