This is a note to let you know that I've just added the patch titled
bpf: fix bpf_dynptr_slice() to stop return an ERR_PTR.
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-fix-bpf_dynptr_slice-to-stop-return-an-err_ptr.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 673d4c819b0c4f534b32d5111d8799a42db53e99
Author: Kui-Feng Lee <thinker.li@xxxxxxxxx>
Date: Thu Aug 3 16:12:06 2023 -0700
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 <dan.carpenter@xxxxxxxxxx>
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 <alexei.starovoitov@xxxxxxxxx>
Signed-off-by: Kui-Feng Lee <thinker.li@xxxxxxxxx>
Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230803231206.1060485-1-thinker.li@xxxxxxxxx
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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);
