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hv_netvsc: Allocate the recv_buf buffers after NVSP_MSG1_TYPE_SEND_RECV_BUF

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The recv_buf buffers are allocated in netvsc_device_add().  Later in
netvsc_init_buf() the response to NVSP_MSG1_TYPE_SEND_RECV_BUF allows
the host to set up a recv_section_size that could be bigger than the
(default) value used for that allocation.  The host-controlled value
could be used by a malicious host to bypass the check on the packet's
length in netvsc_receive() and hence to overflow the recv_buf buffer.

Move the allocation of the recv_buf buffers into netvsc_init_but().

Reported-by: Juan Vazquez <juvazq@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Fixes: 0ba35fe91c ("hv_netvsc: Copy packets sent by Hyper-V out of the receive buffer")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Andrea Parri (Microsoft) 2021-02-03 12:35:12 +01:00 committed by Jakub Kicinski
parent 6b4950d950
commit 0102eeedb7
1 changed files with 11 additions and 7 deletions
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18
drivers/net/hyperv/netvsc.c
View file

@ -311,7 +311,7 @@ static int netvsc_init_buf(struct hv_device *device,
struct nvsp_message *init_packet;
unsigned int buf_size;
size_t map_words;
int ret = 0;
int i, ret = 0;
/* Get receive buffer area. */
buf_size = device_info->recv_sections * device_info->recv_section_size;
@ -405,6 +405,16 @@ static int netvsc_init_buf(struct hv_device *device,
goto cleanup;
}
for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
struct netvsc_channel *nvchan = &net_device->chan_table[i];
nvchan->recv_buf = kzalloc(net_device->recv_section_size, GFP_KERNEL);
if (nvchan->recv_buf == NULL) {
ret = -ENOMEM;
goto cleanup;
}
}
/* Setup receive completion ring.
* Add 1 to the recv_section_cnt because at least one entry in a
* ring buffer has to be empty.
@ -1549,12 +1559,6 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
struct netvsc_channel *nvchan = &net_device->chan_table[i];
nvchan->recv_buf = kzalloc(device_info->recv_section_size, GFP_KERNEL);
if (nvchan->recv_buf == NULL) {
ret = -ENOMEM;
goto cleanup2;
}
nvchan->channel = device->channel;
nvchan->net_device = net_device;
u64_stats_init(&nvchan->tx_stats.syncp);