On Fri, Oct 28, 2022 at 7:55 PM Kees Cook <keescook@xxxxxxxxxxxx> wrote: > > If an error (NULL) is returned by krealloc(), callers of realloc_array() > were setting their allocation pointers to NULL, but on error krealloc() > does not touch the original allocation. This would result in a memory > resource leak. Instead, free the old allocation on the error handling > path. > > Cc: Alexei Starovoitov <ast@xxxxxxxxxx> > Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx> > Cc: John Fastabend <john.fastabend@xxxxxxxxx> > Cc: Andrii Nakryiko <andrii@xxxxxxxxxx> > Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx> > Cc: Song Liu <song@xxxxxxxxxx> > Cc: Yonghong Song <yhs@xxxxxx> > Cc: KP Singh <kpsingh@xxxxxxxxxx> > Cc: Stanislav Fomichev <sdf@xxxxxxxxxx> > Cc: Hao Luo <haoluo@xxxxxxxxxx> > Cc: Jiri Olsa <jolsa@xxxxxxxxxx> > Cc: bpf@xxxxxxxxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Reviewed-by: Bill Wendling <morbo@xxxxxxxxxx> > --- > kernel/bpf/verifier.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index 014ee0953dbd..eb8c34db74c7 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -1027,12 +1027,17 @@ static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t > */ > static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size) > { > + void *new_arr; > + > if (!new_n || old_n == new_n) > goto out; > > - arr = krealloc_array(arr, new_n, size, GFP_KERNEL); > - if (!arr) > + new_arr = krealloc_array(arr, new_n, size, GFP_KERNEL); > + if (!new_arr) { > + kfree(arr); > return NULL; > + } > + arr = new_arr; > > if (new_n > old_n) > memset(arr + old_n * size, 0, (new_n - old_n) * size); > -- > 2.34.1 >