Merge branch 'linus' into sched/core, to resolve semantic conflict

[linux-2.6-microblaze.git] / kernel / trace / bpf_trace.c

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a690391..818cf8a 100644 (file)
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -181,6 +181,16 @@ bpf_probe_read_user_str_common(void *dst, u32 size,
 {
        int ret;
 
+       /*
+        * NB: We rely on strncpy_from_user() not copying junk past the NUL
+        * terminator into `dst`.
+        *
+        * strncpy_from_user() does long-sized strides in the fast path. If the
+        * strncpy does not mask out the bytes after the NUL in `unsafe_ptr`,
+        * then there could be junk after the NUL in `dst`. If user takes `dst`
+        * and keys a hash map with it, then semantically identical strings can
+        * occupy multiple entries in the map.
+        */
        ret = strncpy_from_user_nofault(dst, unsafe_ptr, size);
        if (unlikely(ret < 0))
                memset(dst, 0, size);
@@ -1198,7 +1208,7 @@ static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size,
        *btf = bpf_get_btf_vmlinux();
 
        if (IS_ERR_OR_NULL(*btf))
-               return PTR_ERR(*btf);
+               return IS_ERR(*btf) ? PTR_ERR(*btf) : -EINVAL;
 
        if (ptr->type_id > 0)
                *btf_id = ptr->type_id;