From: Chenyuan Mi michenyuan@huawei.com
[ Upstream commit 49d736313d0975ddeb156f4f59801da833f78b30 ]
In function size_from_channelarray(), the return value 'bytes' is defined as int type. However, the calcution of 'bytes' in this function is designed to use the unsigned int type. So it is necessary to change 'bytes' type to unsigned int to avoid integer overflow.
The size_from_channelarray() is called in main() function, its return value is directly multipled by 'buf_len' and then used as the malloc() parameter. The 'buf_len' is completely controllable by user, thus a multiplication overflow may occur here. This could allocate an unexpected small area.
Signed-off-by: Chenyuan Mi michenyuan@huawei.com Link: https://lore.kernel.org/r/20230725092407.62545-1-michenyuan@huawei.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/iio/iio_generic_buffer.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/tools/iio/iio_generic_buffer.c b/tools/iio/iio_generic_buffer.c index f8deae4e26a15..44bbf80f0cfdd 100644 --- a/tools/iio/iio_generic_buffer.c +++ b/tools/iio/iio_generic_buffer.c @@ -51,9 +51,9 @@ enum autochan { * Has the side effect of filling the channels[i].location values used * in processing the buffer output. **/ -static int size_from_channelarray(struct iio_channel_info *channels, int num_channels) +static unsigned int size_from_channelarray(struct iio_channel_info *channels, int num_channels) { - int bytes = 0; + unsigned int bytes = 0; int i = 0;
while (i < num_channels) { @@ -348,7 +348,7 @@ int main(int argc, char **argv) ssize_t read_size; int dev_num = -1, trig_num = -1; char *buffer_access = NULL; - int scan_size; + unsigned int scan_size; int noevents = 0; int notrigger = 0; char *dummy; @@ -674,7 +674,16 @@ int main(int argc, char **argv) }
scan_size = size_from_channelarray(channels, num_channels); - data = malloc(scan_size * buf_len); + + size_t total_buf_len = scan_size * buf_len; + + if (scan_size > 0 && total_buf_len / scan_size != buf_len) { + ret = -EFAULT; + perror("Integer overflow happened when calculate scan_size * buf_len"); + goto error; + } + + data = malloc(total_buf_len); if (!data) { ret = -ENOMEM; goto error;