The `readlink(path, buf, sizeof(buf))` call reads at most sizeof(buf)
bytes and *does not* append null-terminator to buf. With respect to
that, fix two pieces in get_fd_type:
1. Change the truncation check to contain sizeof(buf) rather than
sizeof(path).
2. Append null-terminator to buf.
Reported by Coverity.
Signed-off-by: Viktor Malik <vmalik@xxxxxxxxxx>
---
tools/bpf/bpftool/common.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index 9b75639434b8..0a764426d935 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -461,10 +461,11 @@ int get_fd_type(int fd)
p_err("can't read link type: %s", strerror(errno));
return -1;
}
- if (n == sizeof(path)) {
+ if (n == sizeof(buf)) {
p_err("can't read link type: path too long!");
return -1;
}
+ buf[n] = '\0';
if (strstr(buf, "bpf-map"))
return BPF_OBJ_MAP;
--
2.48.1
