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From: Jordy Zomer <jordy@pwning.systems>
To: linux-kernel@vger.kernel.org
Cc: Jordy Zomer <jordy@pwning.systems>,
	Oded Gabbay <ogabbay@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Ofir Bitton <obitton@habana.ai>,
	Dani Liberman <dliberman@habana.ai>,
	Omer Shpigelman <oshpigelman@habana.ai>,
	Sagiv Ozeri <sozeri@habana.ai>,
	Yuri Nudelman <ynudelman@habana.ai>,
	farah kassabri <fkassabri@habana.ai>,
	Koby Elbaz <kelbaz@habana.ai>
Subject: [PATCHv2] habanalabs: fix potential spectre v1 gadgets
Date: Wed,  2 Feb 2022 18:19:24 +0100	[thread overview]
Message-ID: <20220202171931.3525220-1-jordy@pwning.systems> (raw)
In-Reply-To: <CAFCwf12QygXk=8WbH9qDhyyqKY6ZGVCUSJM93viQ0armc8dgfg@mail.gmail.com>

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.

Thanks for noticing Oded, made the changes.

Signed-off-by: Jordy Zomer <jordy@pwning.systems>

---
Changes v1 -> v2: Added the correct offsets
---
 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


  reply	other threads:[~2022-02-02 17:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-01 17:24 [PATCH] habanalabs: fix potential spectre v1 gadgets Jordy Zomer
2022-02-02  7:50 ` Oded Gabbay
2022-02-02 10:22   ` Oded Gabbay
2022-02-02 17:19     ` Jordy Zomer [this message]
2022-02-02 19:02       ` [PATCHv2] " Greg Kroah-Hartman
2022-02-02 19:11         ` [PATCHv3] " Jordy Zomer
2022-02-02 19:13           ` Jordy Zomer
2022-02-02 21:01           ` Andrew Cooper

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