[PATCH 2/5] hw/net/rocker: Don't assume h_proto is aligned in eth_strip_vlan_ex()
From: Peter Maydell <hidden>
Date: 2026-02-12 14:11:59
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
In eth_strip_vlan_ex() we take a pointer to the eth_header h_proto field into a local uint16_t* variable, and then later in the function we dereference that pointer. This isn't safe, because the eth_header struct may not be aligned, and if we mark the struct as QEMU_PACKED then gcc will complain about taking the address of a field in a packed struct. Instead, make the local variable be a void* and use the appropriate functions for accessing 16 bits of possibly unaligned data through it. Signed-off-by: Peter Maydell <redacted> --- net/eth.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/eth.c b/net/eth.c
index 3f680cc033..12ec316e24 100644
--- a/net/eth.c
+++ b/net/eth.c@@ -274,7 +274,7 @@ eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, size_t iovoff, int index, uint16_t *payload_offset, uint16_t *tci) { struct vlan_header vlan_hdr; - uint16_t *new_ehdr_proto; + void *new_ehdr_proto; size_t new_ehdr_size; size_t copied;
@@ -298,7 +298,7 @@ eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, size_t iovoff, int index, return 0; } - if (copied < new_ehdr_size || be16_to_cpu(*new_ehdr_proto) != vet) { + if (copied < new_ehdr_size || lduw_be_p(new_ehdr_proto) != vet) { return 0; }
@@ -308,7 +308,7 @@ eth_strip_vlan_ex(const struct iovec *iov, int iovcnt, size_t iovoff, int index, return 0; } - *new_ehdr_proto = vlan_hdr.h_proto; + stw_he_p(new_ehdr_proto, vlan_hdr.h_proto); *payload_offset = iovoff + new_ehdr_size + sizeof(vlan_hdr); *tci = be16_to_cpu(vlan_hdr.h_tci);
--
2.43.0