From: Harshvardhan Jha <harshvardhan.jha@xxxxxxxxxx> [ Upstream commit 77541f78eadfe9fdb018a7b8b69f0f2af2cf4b82 ] The list_for_each_entry() iterator, "adapter" in this code, can never be NULL. If we exit the loop without finding the correct adapter then "adapter" points invalid memory that is an offset from the list head. This will eventually lead to memory corruption and presumably a kernel crash. Link: https://lore.kernel.org/r/20210708074642.23599-1-harshvardhan.jha@xxxxxxxxxx Acked-by: Sumit Saxena <sumit.saxena@xxxxxxxxxxxx> Signed-off-by: Harshvardhan Jha <harshvardhan.jha@xxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/scsi/megaraid/megaraid_mm.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/scsi/megaraid/megaraid_mm.c b/drivers/scsi/megaraid/megaraid_mm.c index 4cf9ed96414f..d61df49e4e1b 100644 --- a/drivers/scsi/megaraid/megaraid_mm.c +++ b/drivers/scsi/megaraid/megaraid_mm.c @@ -250,7 +250,7 @@ mraid_mm_get_adapter(mimd_t __user *umimd, int *rval) mimd_t mimd; uint32_t adapno; int iterator; - + bool is_found; if (copy_from_user(&mimd, umimd, sizeof(mimd_t))) { *rval = -EFAULT; @@ -266,12 +266,16 @@ mraid_mm_get_adapter(mimd_t __user *umimd, int *rval) adapter = NULL; iterator = 0; + is_found = false; list_for_each_entry(adapter, &adapters_list_g, list) { - if (iterator++ == adapno) break; + if (iterator++ == adapno) { + is_found = true; + break; + } } - if (!adapter) { + if (!is_found) { *rval = -ENODEV; return NULL; } @@ -739,6 +743,7 @@ ioctl_done(uioc_t *kioc) uint32_t adapno; int iterator; mraid_mmadp_t* adapter; + bool is_found; /* * When the kioc returns from driver, make sure it still doesn't @@ -761,19 +766,23 @@ ioctl_done(uioc_t *kioc) iterator = 0; adapter = NULL; adapno = kioc->adapno; + is_found = false; con_log(CL_ANN, ( KERN_WARNING "megaraid cmm: completed " "ioctl that was timedout before\n")); list_for_each_entry(adapter, &adapters_list_g, list) { - if (iterator++ == adapno) break; + if (iterator++ == adapno) { + is_found = true; + break; + } } kioc->timedout = 0; - if (adapter) { + if (is_found) mraid_mm_dealloc_kioc( adapter, kioc ); - } + } else { wake_up(&wait_q); -- 2.30.2
