bpf: ensure all memory is initialized in bpf_get_current_comm

BPF helpers that take an ARG_PTR_TO_UNINIT_MEM must ensure that all of
the memory is set, including beyond the end of the string.

Signed-off-by: Barret Rhoden <brho@google.com>
Link: https://lore.kernel.org/r/20230407001808.1622968-1-brho@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 6be16db..b6a5cda 100644 (file)
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -258,7 +258,7 @@ BPF_CALL_2(bpf_get_current_comm, char *, buf, u32, size)
                goto err_clear;
 
        /* Verifier guarantees that size > 0 */
-       strscpy(buf, task->comm, size);
+       strscpy_pad(buf, task->comm, size);
        return 0;
 err_clear:
        memset(buf, 0, size);