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-rw-r--r--kernel/bpf/helpers.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 50da680c479f..ad7a0573f71b 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -163,17 +163,26 @@ static u64 bpf_get_current_comm(u64 r1, u64 size, u64 r3, u64 r4, u64 r5)
struct task_struct *task = current;
char *buf = (char *) (long) r1;
- if (!task)
- return -EINVAL;
+ if (unlikely(!task))
+ goto err_clear;
- strlcpy(buf, task->comm, min_t(size_t, size, sizeof(task->comm)));
+ strncpy(buf, task->comm, size);
+
+ /* Verifier guarantees that size > 0. For task->comm exceeding
+ * size, guarantee that buf is %NUL-terminated. Unconditionally
+ * done here to save the size test.
+ */
+ buf[size - 1] = 0;
return 0;
+err_clear:
+ memset(buf, 0, size);
+ return -EINVAL;
}
const struct bpf_func_proto bpf_get_current_comm_proto = {
.func = bpf_get_current_comm,
.gpl_only = false,
.ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_STACK,
+ .arg1_type = ARG_PTR_TO_RAW_STACK,
.arg2_type = ARG_CONST_STACK_SIZE,
};