scsi: mptfusion: Fix double fetch bug in ioctl
Tom Hatskevich reported that we look up "iocp" then, in the called functions we do a second copy_from_user() and look it up again. The problem that could cause is: drivers/message/fusion/mptctl.c 674 /* All of these commands require an interrupt or 675 * are unknown/illegal. 676 */ 677 if ((ret = mptctl_syscall_down(iocp, nonblock)) != 0) ^^^^ We take this lock. 678 return ret; 679 680 if (cmd == MPTFWDOWNLOAD) 681 ret = mptctl_fw_download(arg); ^^^ Then the user memory changes and we look up "iocp" again but a different one so now we are holding the incorrect lock and have a race condition. 682 else if (cmd == MPTCOMMAND) 683 ret = mptctl_mpt_command(arg); The security impact of this bug is not as bad as it could have been because these operations are all privileged and root already has enormous destructive power. But it's still worth fixing. This patch passes the "iocp" pointer to the functions to avoid the second lookup. That deletes 100 lines of code from the driver so it's a nice clean up as well. Link: https://lore.kernel.org/r/20200114123414.GA7957@kadamReported-by: Tom Hatskevich <tom2001tom.23@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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