diff options
| author | Lee Jones <lee@kernel.org> | 2023-04-20 08:27:18 +0100 |
|---|---|---|
| committer | Jassi Brar <jaswinder.singh@linaro.org> | 2023-05-04 00:53:31 -0500 |
| commit | 2d1e952a2b8e5e92d8d55ac88a7cf7ca5ea591ad (patch) | |
| tree | 795e8344aa6eb9f378584d1abc545f482cb50b76 /drivers/mailbox | |
| parent | be884585852e7d8336e765504399972b3034a89f (diff) | |
mailbox: mailbox-test: Fix potential double-free in mbox_test_message_write()
If a user can make copy_from_user() fail, there is a potential for
UAF/DF due to a lack of locking around the allocation, use and freeing
of the data buffers.
This issue is not theoretical. I managed to author a POC for it:
BUG: KASAN: double-free in kfree+0x5c/0xac
Free of addr ffff29280be5de00 by task poc/356
CPU: 1 PID: 356 Comm: poc Not tainted 6.1.0-00001-g961aa6552c04-dirty #20
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace.part.0+0xe0/0xf0
show_stack+0x18/0x40
dump_stack_lvl+0x64/0x80
print_report+0x188/0x48c
kasan_report_invalid_free+0xa0/0xc0
____kasan_slab_free+0x174/0x1b0
__kasan_slab_free+0x18/0x24
__kmem_cache_free+0x130/0x2e0
kfree+0x5c/0xac
mbox_test_message_write+0x208/0x29c
full_proxy_write+0x90/0xf0
vfs_write+0x154/0x440
ksys_write+0xcc/0x180
__arm64_sys_write+0x44/0x60
invoke_syscall+0x60/0x190
el0_svc_common.constprop.0+0x7c/0x160
do_el0_svc+0x40/0xf0
el0_svc+0x2c/0x6c
el0t_64_sync_handler+0xf4/0x120
el0t_64_sync+0x18c/0x190
Allocated by task 356:
kasan_save_stack+0x3c/0x70
kasan_set_track+0x2c/0x40
kasan_save_alloc_info+0x24/0x34
__kasan_kmalloc+0xb8/0xc0
kmalloc_trace+0x58/0x70
mbox_test_message_write+0x6c/0x29c
full_proxy_write+0x90/0xf0
vfs_write+0x154/0x440
ksys_write+0xcc/0x180
__arm64_sys_write+0x44/0x60
invoke_syscall+0x60/0x190
el0_svc_common.constprop.0+0x7c/0x160
do_el0_svc+0x40/0xf0
el0_svc+0x2c/0x6c
el0t_64_sync_handler+0xf4/0x120
el0t_64_sync+0x18c/0x190
Freed by task 357:
kasan_save_stack+0x3c/0x70
kasan_set_track+0x2c/0x40
kasan_save_free_info+0x38/0x5c
____kasan_slab_free+0x13c/0x1b0
__kasan_slab_free+0x18/0x24
__kmem_cache_free+0x130/0x2e0
kfree+0x5c/0xac
mbox_test_message_write+0x208/0x29c
full_proxy_write+0x90/0xf0
vfs_write+0x154/0x440
ksys_write+0xcc/0x180
__arm64_sys_write+0x44/0x60
invoke_syscall+0x60/0x190
el0_svc_common.constprop.0+0x7c/0x160
do_el0_svc+0x40/0xf0
el0_svc+0x2c/0x6c
el0t_64_sync_handler+0xf4/0x120
el0t_64_sync+0x18c/0x190
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Diffstat (limited to 'drivers/mailbox')
| -rw-r--r-- | drivers/mailbox/mailbox-test.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c index 51e62817f243..c4a705c30331 100644 --- a/drivers/mailbox/mailbox-test.c +++ b/drivers/mailbox/mailbox-test.c @@ -12,6 +12,7 @@ #include <linux/kernel.h> #include <linux/mailbox_client.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/poll.h> @@ -39,6 +40,7 @@ struct mbox_test_device { char *signal; char *message; spinlock_t lock; + struct mutex mutex; wait_queue_head_t waitq; struct fasync_struct *async_queue; struct dentry *root_debugfs_dir; @@ -111,6 +113,8 @@ static ssize_t mbox_test_message_write(struct file *filp, return -EINVAL; } + mutex_lock(&tdev->mutex); + tdev->message = kzalloc(MBOX_MAX_MSG_LEN, GFP_KERNEL); if (!tdev->message) return -ENOMEM; @@ -145,6 +149,8 @@ out: kfree(tdev->message); tdev->signal = NULL; + mutex_unlock(&tdev->mutex); + return ret < 0 ? ret : count; } @@ -393,6 +399,7 @@ static int mbox_test_probe(struct platform_device *pdev) platform_set_drvdata(pdev, tdev); spin_lock_init(&tdev->lock); + mutex_init(&tdev->mutex); if (tdev->rx_channel) { tdev->rx_buffer = devm_kzalloc(&pdev->dev, |