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[v12,bpf-next,01/14] tools resolve_btfids: Add size check to get_id function

Message ID 20200825192124.710397-2-jolsa@kernel.org
State New
Headers show
Series bpf: Add d_path helper | expand

Commit Message

Jiri Olsa Aug. 25, 2020, 7:21 p.m. UTC 
To make sure we don't crash on malformed symbols.

Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/bpf/resolve_btfids/main.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
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Patch

diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index 4d9ecb975862..35a172d3d80d 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -199,9 +199,16 @@  static char *get_id(const char *prefix_end)
 	/*
 	 * __BTF_ID__func__vfs_truncate__0
 	 * prefix_end =  ^
+	 * pos        =    ^
 	 */
-	char *p, *id = strdup(prefix_end + sizeof("__") - 1);
+	int len = strlen(prefix_end);
+	int pos = sizeof("__") - 1;
+	char *p, *id;
 
+	if (pos >= len)
+		return NULL;
+
+	id = strdup(prefix_end + pos);
 	if (id) {
 		/*
 		 * __BTF_ID__func__vfs_truncate__0