This is a note to let you know that I've just added the patch titled
bpf: tcp: Mark bpf_load_hdr_opt() arg2 as read-write
to the 6.12-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-tcp-mark-bpf_load_hdr_opt-arg2-as-read-write.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 646b97f7912eb0a33dd46990319fdc8c66f1cd5b
Author: Daniel Xu <dxu@xxxxxxxxx>
Date: Tue Jan 14 13:28:43 2025 -0700
bpf: tcp: Mark bpf_load_hdr_opt() arg2 as read-write
[ Upstream commit 8ac412a3361173e3000b16167af3d1f6f90af613 ]
MEM_WRITE attribute is defined as: "Non-presence of MEM_WRITE means that
MEM is only being read". bpf_load_hdr_opt() both reads and writes from
its arg2 - void *search_res.
This matters a lot for the next commit where we more precisely track
stack accesses. Without this annotation, the verifier will make false
assumptions about the contents of memory written to by helpers and
possibly prune valid branches.
Fixes: 6fad274f06f0 ("bpf: Add MEM_WRITE attribute")
Acked-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Signed-off-by: Daniel Xu <dxu@xxxxxxxxx>
Link: https://lore.kernel.org/r/730e45f8c39be2a5f3d8c4406cceca9d574cbf14.1736886479.git.dxu@xxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/core/filter.c b/net/core/filter.c
index 46da488ff0703..a2f990bf51e5e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7662,7 +7662,7 @@ static const struct bpf_func_proto bpf_sock_ops_load_hdr_opt_proto = {
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
- .arg2_type = ARG_PTR_TO_MEM,
+ .arg2_type = ARG_PTR_TO_MEM | MEM_WRITE,
.arg3_type = ARG_CONST_SIZE,
.arg4_type = ARG_ANYTHING,
};
