From 83a56d74482ef6b6cc9311b14bf9ea23573f5d4e Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Thu, 13 Feb 2025 12:05:17 +0100
Subject: [PATCH] api: fix seccomp_export_bpf_mem out-of-bounds read

*len is the length of the destination buffer, but program->blks is
probably not anywhere near that long.  It's already been checked above
that BPF_PGM_SIZE(program) is less than or equal to *len, so that's
the correct value to use here to avoid either reading or writing too
much.

I noticed this because tests/11-basic-basic_errors started failing on
musl after e797591 ("all: add seccomp_precompute() functionality").

Upstream-Status: Backport [https://github.com/seccomp/libseccomp/commit/dd759e8c4f5685b526638fba9ec4fc24c37c9aec]
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Acked-by: Tom Hromatka <tom.hromatka@oracle.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
(imported from commit e8dbc6b555fb936bdfb8ab86f9a45fda96a8b7a2)
Signed-off-by: Khem Raj <raj.khem@gmail.com>
---
 src/api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/api.c b/src/api.c
index adccef3..65a277a 100644
--- a/src/api.c
+++ b/src/api.c
@@ -786,7 +786,7 @@ API int seccomp_export_bpf_mem(const scmp_filter_ctx ctx, void *buf,
 		if (BPF_PGM_SIZE(program) > *len)
 			rc = _rc_filter(-ERANGE);
 		else
-			memcpy(buf, program->blks, *len);
+			memcpy(buf, program->blks, BPF_PGM_SIZE(program));
 	}
 	*len = BPF_PGM_SIZE(program);
 
