Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Tue, 11 Jul 2023 11:20:44 +0300 | From | Dan Carpenter <> | Subject | [PATCH 1/5 v4] accel/qaic: tighten bounds checking in encode_message() |
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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
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