2022-02-02 19:49:48

by Greg KH

[permalink] [raw]
Subject: Re: [PATCHv2] habanalabs: fix potential spectre v1 gadgets

On Wed, Feb 02, 2022 at 06:19:24PM +0100, Jordy Zomer wrote:
> It appears like nr could be a Spectre v1 gadget as it's supplied by a
> user and used as an array index. Prevent the contents
> of kernel memory from being leaked to userspace via speculative
> execution by using array_index_nospec.

Can you wrap your lines in a standard way?


>
> Thanks for noticing Oded, made the changes.

This line should not be in the changelog :(

thanks,

greg k-h


2022-02-07 18:11:52

by Jordy Zomer

[permalink] [raw]
Subject: [PATCHv3] habanalabs: fix potential spectre v1 gadgets

It appears like nr could be a Spectre v1 gadget as it's supplied by a
user and used as an array index. Prevent the contents of kernel memory
being leaked to userspace via speculative execution by using
array_index_nospec.

Signed-off-by: Jordy Zomer <[email protected]>

---
Changes v1 -> v2: Added the correct offsets
Changes v2 -> v3: Fixed line-wrapping
---
drivers/misc/habanalabs/common/habanalabs_ioctl.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/misc/habanalabs/common/habanalabs_ioctl.c b/drivers/misc/habanalabs/common/habanalabs_ioctl.c
index 3ba3a8ffda3e..c1cdf712a10d 100644
--- a/drivers/misc/habanalabs/common/habanalabs_ioctl.c
+++ b/drivers/misc/habanalabs/common/habanalabs_ioctl.c
@@ -14,6 +14,7 @@
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
+#include <linux/nospec.h>

static u32 hl_debug_struct_size[HL_DEBUG_OP_TIMESTAMP + 1] = {
[HL_DEBUG_OP_ETR] = sizeof(struct hl_debug_params_etr),
@@ -849,6 +850,7 @@ long hl_ioctl(struct file *filep, unsigned int cmd, unsigned long arg)
}

if ((nr >= HL_COMMAND_START) && (nr < HL_COMMAND_END)) {
+ nr = array_index_nospec(nr, HL_COMMAND_END);
ioctl = &hl_ioctls[nr];
} else {
dev_err(hdev->dev, "invalid ioctl: pid=%d, nr=0x%02x\n",
@@ -872,6 +874,7 @@ long hl_ioctl_control(struct file *filep, unsigned int cmd, unsigned long arg)
}

if (nr == _IOC_NR(HL_IOCTL_INFO)) {
+ nr = array_index_nospec(nr, _IOC_NR(HL_IOCTL_INFO)+1);
ioctl = &hl_ioctls_control[nr];
} else {
dev_err(hdev->dev_ctrl, "invalid ioctl: pid=%d, nr=0x%02x\n",
--
2.27.0