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nexthop: Annotate struct nh_group with __counted_by

PATCH Applied Kees Cook 3 participants 3 messages Oct 4, 2023 – Oct 6, 2023

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Kees Cook

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#0 lore raw

PATCH 1/1 nexthop: Annotate struct nh_group with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

As found with Coccinelle[1], add __counted_by for struct nh_group.

---
 include/net/nexthop.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
include/net/nexthop.h +1 -1
index 8f5a2ab45920..d92046a4a078 100644
@@ -126,7 +126,7 @@ struct nh_group {
 	bool			has_v4;
 
 	struct nh_res_table __rcu *res_table;
-	struct nh_grp_entry	nh_entries[];
+	struct nh_grp_entry	nh_entries[] __counted_by(num_nh);
 };
 
 struct nexthop {
Signature · 1 line
2.34.1
maintainer Reviewed-by on v1 1/1
#1 lore raw
Quoted 16 lines · Kees Cook

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

As found with Coccinelle[1], add __counted_by for struct nh_group.

Quoted 4 lines
---
 include/net/nexthop.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
#2 lore raw
In reply to Kees Cook
This patch was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Hello:

This patch was applied to netdev/net-next.git (main) by David S. Miller <[email protected]>:

Quoted 9 lines · On Tue, 3 Oct 2023 18:44:49 -0700 you wrote:

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

As found with Coccinelle[1], add __counted_by for struct nh_group.

[...]

Here is the summary with links:
- nexthop: Annotate struct nh_group with __counted_by

    https://git.kernel.org/netdev/net-next/c/2a92fccdaca8

You are awesome, thank you!

Signature · 2 lines
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