[PATCH] bpf: Fix potential integer overflow in resolve_btfids

[PATCH] bpf: Fix potential integer overflow in resolve_btfids

[Friedrich Vock]

err is a 32-bit integer, but elf_update returns an off_t, which is
64-bit at least on 64-bit platforms. If symbols_patch is called on a
binary between 2-4GB in size, the result will be negative when cast to
a 32-bit integer, which the code assumes means an error occurred. This
can wrongly trigger build failures when building very large kernel
images.

Signed-off-by: Friedrich Vock <friedrich.vock@gmx.de>

Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Cc: Jiri Olsa <jolsa@kernel.org>
---
 tools/bpf/resolve_btfids/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index d9520cb826b31..af393c7dee1f1 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -728,7 +728,7 @@ static int sets_patch(struct object *obj)

 static int symbols_patch(struct object *obj)
 {
-	int err;
+	off_t err;

 	if (__symbols_patch(obj, &obj->structs)  ||
 	    __symbols_patch(obj, &obj->unions)   ||
--
2.45.0

Re: [PATCH] bpf: Fix potential integer overflow in resolve_btfids

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Tue, 14 May 2024 09:09:31 +0200 you wrote:
> err is a 32-bit integer, but elf_update returns an off_t, which is
> 64-bit at least on 64-bit platforms. If symbols_patch is called on a
> binary between 2-4GB in size, the result will be negative when cast to
> a 32-bit integer, which the code assumes means an error occurred. This
> can wrongly trigger build failures when building very large kernel
> images.
> 
> [...]

Here is the summary with links:
  - bpf: Fix potential integer overflow in resolve_btfids
    https://git.kernel.org/bpf/bpf/c/44382b3ed6b2

You are awesome, thank you!
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