* [PATCH] wireguard: allowedips: Prevent unaligned memory accesses
@ 2024-07-03 16:20 Helge Deller
2024-07-03 18:11 ` Jason A. Donenfeld
0 siblings, 1 reply; 2+ messages in thread
From: Helge Deller @ 2024-07-03 16:20 UTC (permalink / raw)
To: Jason A. Donenfeld, wireguard, netdev, linux-kernel, linux-parisc
On the parisc platform the Linux kernel issues kernel warnings because
swap_endian() tries to load a 128-bit IPv6 address from an unaligned
memory location:
Kernel: unaligned access to 0x55f4688c in wg_allowedips_insert_v6+0x2c/0x80 [wireguard] (iir 0xf3010df)
Kernel: unaligned access to 0x55f46884 in wg_allowedips_insert_v6+0x38/0x80 [wireguard] (iir 0xf2010dc)
Avoid such unaligned memory accesses by instead using the
get_unaligned_be64() helper macro.
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c
index 0ba714ca5185..daf967130b72 100644
--- a/drivers/net/wireguard/allowedips.c
+++ b/drivers/net/wireguard/allowedips.c
@@ -15,8 +15,8 @@ static void swap_endian(u8 *dst, const u8 *src, u8 bits)
if (bits == 32) {
*(u32 *)dst = be32_to_cpu(*(const __be32 *)src);
} else if (bits == 128) {
- ((u64 *)dst)[0] = be64_to_cpu(((const __be64 *)src)[0]);
- ((u64 *)dst)[1] = be64_to_cpu(((const __be64 *)src)[1]);
+ ((u64 *)dst)[0] = get_unaligned_be64(src);
+ ((u64 *)dst)[1] = get_unaligned_be64(src[8]);
}
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] wireguard: allowedips: Prevent unaligned memory accesses
2024-07-03 16:20 [PATCH] wireguard: allowedips: Prevent unaligned memory accesses Helge Deller
@ 2024-07-03 18:11 ` Jason A. Donenfeld
0 siblings, 0 replies; 2+ messages in thread
From: Jason A. Donenfeld @ 2024-07-03 18:11 UTC (permalink / raw)
To: Helge Deller; +Cc: wireguard, netdev, linux-kernel, linux-parisc
Hi Helge,
On Wed, Jul 03, 2024 at 06:20:19PM +0200, Helge Deller wrote:
> On the parisc platform the Linux kernel issues kernel warnings because
> swap_endian() tries to load a 128-bit IPv6 address from an unaligned
> memory location:
> Kernel: unaligned access to 0x55f4688c in wg_allowedips_insert_v6+0x2c/0x80 [wireguard] (iir 0xf3010df)
> Kernel: unaligned access to 0x55f46884 in wg_allowedips_insert_v6+0x38/0x80 [wireguard] (iir 0xf2010dc)
>
> Avoid such unaligned memory accesses by instead using the
> get_unaligned_be64() helper macro.
>
> Signed-off-by: Helge Deller <deller@gmx.de>
>
> diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c
> index 0ba714ca5185..daf967130b72 100644
> --- a/drivers/net/wireguard/allowedips.c
> +++ b/drivers/net/wireguard/allowedips.c
> @@ -15,8 +15,8 @@ static void swap_endian(u8 *dst, const u8 *src, u8 bits)
> if (bits == 32) {
> *(u32 *)dst = be32_to_cpu(*(const __be32 *)src);
> } else if (bits == 128) {
> - ((u64 *)dst)[0] = be64_to_cpu(((const __be64 *)src)[0]);
> - ((u64 *)dst)[1] = be64_to_cpu(((const __be64 *)src)[1]);
> + ((u64 *)dst)[0] = get_unaligned_be64(src);
Ahh, right, in6_addr only has a u32 member, not a u64 member, so that's
potentially unaligned.
> + ((u64 *)dst)[1] = get_unaligned_be64(src[8]);
src[8] is not correct, however. (This crashes; did you test it?) I've
fixed it up and put it in the wireguard tree:
https://git.kernel.org/pub/scm/linux/kernel/git/zx2c4/wireguard-linux.git/commit/?id=ad3d9eef8e1b304b243e63124581f97c88ce7ff9
I'll push this up to net.git soon. Thanks for the patch.
Jason
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2024-07-03 18:11 ` Jason A. Donenfeld
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