lkml.org 
[lkml]   [2023]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH 1/5 v4] accel/qaic: tighten bounds checking in encode_message()
There are several issues in this code.  The check at the start of the
loop:

if (user_len >= user_msg->len) {

This check does not ensure that we have enough space for the trans_hdr
(8 bytes). Instead the check needs to be:

if (user_len > user_msg->len - sizeof(*trans_hdr)) {

That subtraction is done as an unsigned long we want to avoid
negatives. Add a lower bound to the start of the function.

if (user_msg->len < sizeof(*trans_hdr))

There is a second integer underflow which can happen if
trans_hdr->len is zero inside the encode_passthrough() function.

memcpy(out_trans->data, in_trans->data, in_trans->hdr.len - sizeof(in_trans->hdr));

Instead of adding a check to encode_passthrough() it's better to check
in this central place. Add that check:

if (trans_hdr->len < sizeof(trans_hdr)

The final concern is that the "user_len + trans_hdr->len" might have an
integer overflow bug. Use size_add() to prevent that.

- if (user_len + trans_hdr->len > user_msg->len) {
+ if (size_add(user_len, trans_hdr->len) > user_msg->len) {

Fixes: 129776ac2e38 ("accel/qaic: Add control path")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
v4: send this patch.
v2: * Fix the >= vs > bug in:

if (user_len > user_msg->len - sizeof(*trans_hdr)) {

* include overflow.h
---
drivers/accel/qaic/qaic_control.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c
index 5c57f7b4494e..2fdd5959c52f 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -14,6 +14,7 @@
#include <linux/mm.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
+#include <linux/overflow.h>
#include <linux/pci.h>
#include <linux/scatterlist.h>
#include <linux/types.h>
@@ -748,7 +749,8 @@ static int encode_message(struct qaic_device *qdev, struct manage_msg *user_msg,
int ret;
int i;

- if (!user_msg->count) {
+ if (!user_msg->count ||
+ user_msg->len < sizeof(*trans_hdr)) {
ret = -EINVAL;
goto out;
}
@@ -765,12 +767,13 @@ static int encode_message(struct qaic_device *qdev, struct manage_msg *user_msg,
}

for (i = 0; i < user_msg->count; ++i) {
- if (user_len >= user_msg->len) {
+ if (user_len > user_msg->len - sizeof(*trans_hdr)) {
ret = -EINVAL;
break;
}
trans_hdr = (struct qaic_manage_trans_hdr *)(user_msg->data + user_len);
- if (user_len + trans_hdr->len > user_msg->len) {
+ if (trans_hdr->len < sizeof(trans_hdr) ||
+ size_add(user_len, trans_hdr->len) > user_msg->len) {
ret = -EINVAL;
break;
}
--
2.39.2
\
 
 \ /
  Last update: 2023-07-11 10:21    [W:0.096 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site