From 33a154a96e71a34a1bcca9f40da343dbbf7b38b4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 1 Oct 2026 14:52:55 +0000 Subject: selftests/bpf: Test packet range of pointers sharing an id Add tests where two packet pointers share an id and tightening one pointer's umax from its var_off would put it less than their constant distance from the other's umax: with an index & 0x38 capped at 50, the base pointer keeps umax 50, so the pointer 8 bytes further on must keep umax 58, even though its known bits allow at most 56. These refused a valid program or accepted an out-of-bounds access before the fix: - check the advanced copy, load through the base: valid, was refused; - check the base, load the byte at base + 1 through a copy advanced by 8: was accepted; - check base + 4, load 4 bytes at base + 2 through base + 8: reads two bytes past the checked range, was accepted; - the same as the second with data_meta pointers checked against data: was accepted. These pass with and without the fix and cover nearby paths: - subtract an unknown scalar from a checked pointer and load below it (the range is kept across a new id); - reach a load through two paths whose checks cover 8 and 7 bytes after the loaded pointer; the second path must not be pruned by the first; - spill a copy of a pointer, check the pointer, fill the copy and load one byte past the checked range: the load is refused, and the copy has the range of the check. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- include/net/compat.h | 95 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 include/net/compat.h (limited to 'include/net/compat.h') diff --git a/include/net/compat.h b/include/net/compat.h new file mode 100644 index 000000000..84c163f40 --- /dev/null +++ b/include/net/compat.h @@ -0,0 +1,95 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef NET_COMPAT_H +#define NET_COMPAT_H + + +struct sock; + +#include + +struct compat_msghdr { + compat_uptr_t msg_name; /* void * */ + compat_int_t msg_namelen; + compat_uptr_t msg_iov; /* struct compat_iovec * */ + compat_size_t msg_iovlen; + compat_uptr_t msg_control; /* void * */ + compat_size_t msg_controllen; + compat_uint_t msg_flags; +}; + +struct compat_mmsghdr { + struct compat_msghdr msg_hdr; + compat_uint_t msg_len; +}; + +struct compat_cmsghdr { + compat_size_t cmsg_len; + compat_int_t cmsg_level; + compat_int_t cmsg_type; +}; + +struct compat_rtentry { + u32 rt_pad1; + struct sockaddr rt_dst; /* target address */ + struct sockaddr rt_gateway; /* gateway addr (RTF_GATEWAY) */ + struct sockaddr rt_genmask; /* target network mask (IP) */ + unsigned short rt_flags; + short rt_pad2; + u32 rt_pad3; + unsigned char rt_tos; + unsigned char rt_class; + short rt_pad4; + short rt_metric; /* +1 for binary compatibility! */ + compat_uptr_t rt_dev; /* forcing the device at add */ + u32 rt_mtu; /* per route MTU/Window */ + u32 rt_window; /* Window clamping */ + unsigned short rt_irtt; /* Initial RTT */ +}; + +int __get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr *msg, + struct sockaddr __user **save_addr); +int get_compat_msghdr(struct msghdr *, struct compat_msghdr __user *, + struct sockaddr __user **, struct iovec **); +int put_cmsg_compat(struct msghdr*, int, int, int, void *); + +int cmsghdr_from_user_compat_to_kern(struct msghdr *, struct sock *, + unsigned char *, int); + +struct compat_group_req { + __u32 gr_interface; + struct __kernel_sockaddr_storage gr_group + __aligned(4); +} __packed; + +struct compat_group_source_req { + __u32 gsr_interface; + struct __kernel_sockaddr_storage gsr_group + __aligned(4); + struct __kernel_sockaddr_storage gsr_source + __aligned(4); +} __packed; + +struct compat_group_filter { + union { + struct { + __u32 gf_interface_aux; + struct __kernel_sockaddr_storage gf_group_aux + __aligned(4); + __u32 gf_fmode_aux; + __u32 gf_numsrc_aux; + struct __kernel_sockaddr_storage gf_slist[1] + __aligned(4); + } __packed; + struct { + __u32 gf_interface; + struct __kernel_sockaddr_storage gf_group + __aligned(4); + __u32 gf_fmode; + __u32 gf_numsrc; + struct __kernel_sockaddr_storage gf_slist_flex[] + __aligned(4); + } __packed; + }; +} __packed; + +#endif /* NET_COMPAT_H */ -- cgit v1.3.1