In the Linux kernel, the following vulnerability has been resolved:
usb: typec: tcpci: fix NULL pointer issue on shared irq case
The tcpci_irq() may meet below NULL pointer dereference issue:
[ 2.641851] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 [ 2.641951] status 0x1, 0x37f [ 2.650659] Mem abort info: [ 2.656490] ESR = 0x0000000096000004 [ 2.660230] EC = 0x25: DABT (current EL), IL = 32 bits [ 2.665532] SET = 0, FnV = 0 [ 2.668579] EA = 0, S1PTW = 0 [ 2.671715] FSC = 0x04: level 0 translation fault [ 2.676584] Data abort info: [ 2.679459] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 2.684936] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 2.689980] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 2.695284] [0000000000000010] user address but activemm is swapper [ 2.701632] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 2.707883] Modules linked in: [ 2.710936] CPU: 1 UID: 0 PID: 87 Comm: irq/111-2-0051 Not tainted 6.12.0-rc6-06316-g7f63786ad3d1-dirty #4 [ 2.720570] Hardware name: NXP i.MX93 11X11 EVK board (DT) [ 2.726040] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 2.732989] pc : tcpciirq+0x38/0x318 [ 2.736647] lr : tcpciirq+0x14/0x20 [ 2.740295] sp : ffff80008324bd30 [ 2.743597] x29: ffff80008324bd70 x28: ffff800080107894 x27: ffff800082198f70 [ 2.750721] x26: ffff0000050e6680 x25: ffff000004d172ac x24: ffff0000050f0000 [ 2.757845] x23: ffff000004d17200 x22: 0000000000000001 x21: ffff0000050f0000 [ 2.764969] x20: ffff000004d17200 x19: 0000000000000000 x18: 0000000000000001 [ 2.772093] x17: 0000000000000000 x16: ffff80008183d8a0 x15: ffff00007fbab040 [ 2.779217] x14: ffff00007fb918c0 x13: 0000000000000000 x12: 000000000000017a [ 2.786341] x11: 0000000000000001 x10: 0000000000000a90 x9 : ffff80008324bd00 [ 2.793465] x8 : ffff0000050f0af0 x7 : ffff00007fbaa840 x6 : 0000000000000031 [ 2.800589] x5 : 000000000000017a x4 : 0000000000000002 x3 : 0000000000000002 [ 2.807713] x2 : ffff80008324bd3a x1 : 0000000000000010 x0 : 0000000000000000 [ 2.814838] Call trace: [ 2.817273] tcpciirq+0x38/0x318 [ 2.820583] _tcpciirq+0x14/0x20 [ 2.823885] irqthreadfn+0x2c/0xa8 [ 2.827456] irqthread+0x16c/0x2f4 [ 2.830940] kthread+0x110/0x114 [ 2.834164] retfrom_fork+0x10/0x20 [ 2.837738] Code: f9426420 f9001fe0 d2800000 52800201 (f9400a60)
This may happen on shared irq case. Such as two Type-C ports share one irq. After the first port finished tcpciregisterport(), it may trigger interrupt. However, if the interrupt comes by chance the 2nd port finishes devmrequestthreadedirq(), the 2nd port interrupt handler will run at first. Then the above issue happens due to tcpci is still a NULL pointer in tcpciirq() when dereference to regmap.
devmrequestthreadedirq() <-- port1 irq comes disableirq(client->irq); tcpciregisterport()
This will restore the logic to the state before commit (77e85107a771 "usb: typec: tcpci: support edge irq").
However, moving tcpciregisterport() earlier creates a problem when use edge irq because tcpciinit() will be called before devmrequestthreadedirq(). The tcpciinit() writes the ALERTMASK to the hardware to tell it to start generating interrupts but we're not ready to deal with them yet, then the ALERT events may be missed and ALERT line will not recover to high level forever. To avoid the issue, this will also set ALERTMASK register after devmrequestthreadedirq() return.