Re: [PATCH] serial: 8250_pci: Prefer struct_size over open coded arithmetic
From: Andy Shevchenko <hidden>
Date: 2021-09-05 16:14:35
Also in:
linux-hardening, lkml
On Sun, Sep 5, 2021 at 6:58 PM Len Baker [off-list ref] wrote:
As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors. So, use the struct_size() helper to do the arithmetic instead of the argument "size + size * count" in the kzalloc() function.
Makes sense Reviewed-by: Andy Shevchenko <redacted>
quoted hunk ↗ jump to hunk
[1] https://www.kernel.org/doc/html/v5.14/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments Signed-off-by: Len Baker <redacted> --- drivers/tty/serial/8250/8250_pci.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index a808c283883e..b97ade35d4a3 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c@@ -3981,9 +3981,7 @@ pciserial_init_ports(struct pci_dev *dev, const struct pciserial_board *board) nr_ports = rc; } - priv = kzalloc(sizeof(struct serial_private) + - sizeof(unsigned int) * nr_ports, - GFP_KERNEL); + priv = kzalloc(struct_size(priv, line, nr_ports), GFP_KERNEL); if (!priv) { priv = ERR_PTR(-ENOMEM); goto err_deinit; --2.25.1
-- With Best Regards, Andy Shevchenko