From: Kui-Feng Lee Date: Thu, 3 Aug 2023 23:12:06 +0000 (-0700) Subject: bpf: fix bpf_dynptr_slice() to stop return an ERR_PTR. X-Git-Tag: v6.4.16~546 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc958014fa2395a31f786292142a8ac8b88c9648;p=thirdparty%2Fkernel%2Fstable.git bpf: fix bpf_dynptr_slice() to stop return an ERR_PTR. [ Upstream commit 5426700e6841bf72e652e34b5cec68eadf442435 ] Verify if the pointer obtained from bpf_xdp_pointer() is either an error or NULL before returning it. The function bpf_dynptr_slice() mistakenly returned an ERR_PTR. Instead of solely checking for NULL, it should also verify if the pointer returned by bpf_xdp_pointer() is an error or NULL. Reported-by: Dan Carpenter Closes: https://lore.kernel.org/bpf/d1360219-85c3-4a03-9449-253ea905f9d1@moroto.mountain/ Fixes: 66e3a13e7c2c ("bpf: Add bpf_dynptr_slice and bpf_dynptr_slice_rdwr") Suggested-by: Alexei Starovoitov Signed-off-by: Kui-Feng Lee Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20230803231206.1060485-1-thinker.li@gmail.com Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin --- diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index f12565ba136b0..8c5daa841704b 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2218,7 +2218,7 @@ __bpf_kfunc void *bpf_dynptr_slice(const struct bpf_dynptr_kern *ptr, u32 offset case BPF_DYNPTR_TYPE_XDP: { void *xdp_ptr = bpf_xdp_pointer(ptr->data, ptr->offset + offset, len); - if (xdp_ptr) + if (!IS_ERR_OR_NULL(xdp_ptr)) return xdp_ptr; bpf_xdp_copy_buf(ptr->data, ptr->offset + offset, buffer, len, false);