diff mbox series

wireguard: allowedips: Prevent unaligned memory accesses

Message ID ZoV6Q6lWgVRqe7eh@p100 (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series wireguard: allowedips: Prevent unaligned memory accesses | expand

Checks

Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 839 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 3 maintainers not CCed: edumazet@google.com kuba@kernel.org pabeni@redhat.com
netdev/build_clang fail Errors and warnings before: 846 this patch: 17
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 846 this patch: 16
netdev/checkpatch warning WARNING: From:/Signed-off-by: email address mismatch: 'From: Helge Deller <deller@kernel.org>' != 'Signed-off-by: Helge Deller <deller@gmx.de>'
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Helge Deller July 3, 2024, 4:20 p.m. UTC
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>

Comments

Jason A. Donenfeld July 3, 2024, 6:11 p.m. UTC | #1
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
diff mbox series

Patch

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]);
 	}
 }