| Message ID | 20220614173352.GA588327@ubuntu (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Gregory Greenman |
| Headers | show |
| Series | iwlwifi: pcie: Fixed integer overflow in iwl_write_to_user_buf | expand |
On Tue, 2022-06-14 at 10:33 -0700, Hyunwoo Kim wrote: > An integer overflow occurs in the iwl_write_to_user_buf() function, > which is called by the iwl_dbgfs_monitor_data_read() function. > Out of curiosity, how did you find this? johannes
On Wed, Jun 15, 2022 at 09:06:51AM +0200, Johannes Berg wrote: > On Tue, 2022-06-14 at 10:33 -0700, Hyunwoo Kim wrote: > > An integer overflow occurs in the iwl_write_to_user_buf() function, > > which is called by the iwl_dbgfs_monitor_data_read() function. > > > > Out of curiosity, how did you find this? I found it while analyzing several device drivers as a personal hobby. I also want to ask you one question. While analyzing several device drivers, I found several such integer overflow or race condition problems, and made and submitted a patch. https://marc.info/?l=linux-fbdev&m=165497564701256&w=2 https://www.spinics.net/lists/linux-efi/msg24884.html However, there is no response whether this patch has been accepted or rejected. In this case, do I have to send an email to the higher level maintainer? Or do I have to wait? Thanks, Hyunwoo Kim
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c index bd50f52a1aad..fded5d305b11 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c @@ -2854,7 +2854,7 @@ 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)
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> --- drivers/net/wireless/intel/iwlwifi/pcie/trans.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)