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// SPDX-License-Identifier: GPL-2.0
/* Bounds checks for PTR_TO_FLOW_KEYS pointer arithmetic. */
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
/* sizeof(struct bpf_flow_keys) is well under 4096, so +0x1000 is OOB. */
SEC("flow_dissector")
__description("flow_keys: in-bounds constant pointer arithmetic accepted")
__success
__naked void flow_keys_const_inbounds(void)
{
asm volatile (" \
r1 = *(u64 *)(r1 + %[flow_keys]); \
r1 += 8; \
r0 = *(u64 *)(r1 + 0); \
r0 = 0; \
exit; \
" :
: __imm_const(flow_keys, offsetof(struct __sk_buff, flow_keys))
: __clobber_all);
}
SEC("flow_dissector")
__description("flow_keys: OOB via constant pointer arithmetic rejected")
__failure __msg("invalid access to flow keys off=4096 size=8")
__naked void flow_keys_const_oob_read(void)
{
asm volatile (" \
r1 = *(u64 *)(r1 + %[flow_keys]); \
r1 += 4096; \
r0 = *(u64 *)(r1 + 0); \
r0 = 0; \
exit; \
" :
: __imm_const(flow_keys, offsetof(struct __sk_buff, flow_keys))
: __clobber_all);
}
SEC("flow_dissector")
__description("flow_keys: OOB write via constant pointer arithmetic rejected")
__failure __msg("invalid access to flow keys off=4096 size=8")
__naked void flow_keys_const_oob_write(void)
{
asm volatile (" \
r1 = *(u64 *)(r1 + %[flow_keys]); \
r1 += 4096; \
r2 = 0; \
*(u64 *)(r1 + 0) = r2; \
r0 = 0; \
exit; \
" :
: __imm_const(flow_keys, offsetof(struct __sk_buff, flow_keys))
: __clobber_all);
}
/* Equivalent OOB expressed directly in insn->off; this form was always
* rejected and is kept to show both forms now share one diagnostic.
*/
SEC("flow_dissector")
__description("flow_keys: OOB via insn->off rejected")
__failure __msg("invalid access to flow keys off=4096 size=8")
__naked void flow_keys_insn_off_oob(void)
{
asm volatile (" \
r1 = *(u64 *)(r1 + %[flow_keys]); \
r0 = *(u64 *)(r1 + 4096); \
r0 = 0; \
exit; \
" :
: __imm_const(flow_keys, offsetof(struct __sk_buff, flow_keys))
: __clobber_all);
}
SEC("flow_dissector")
__description("flow_keys: variable pointer arithmetic rejected")
__failure __msg("R1 pointer arithmetic on flow_keys prohibited")
__naked void flow_keys_var_read(void)
{
asm volatile (" \
r6 = r1; \
call %[bpf_get_prandom_u32]; \
r0 &= 0xFFFF; \
r1 = *(u64 *)(r6 + %[flow_keys]); \
r1 += r0; \
r0 = *(u64 *)(r1 + 0); \
r0 = 0; \
exit; \
" :
: __imm_const(flow_keys, offsetof(struct __sk_buff, flow_keys)),
__imm(bpf_get_prandom_u32)
: __clobber_all);
}
char _license[] SEC("license") = "GPL";
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