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// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
/* Read an uninitialized value from stack at a fixed offset */
SEC("socket")
__naked int read_uninit_stack_fixed_off(void *ctx)
{
asm volatile (" \
r0 = 0; \
/* force stack depth to be 128 */ \
*(u64*)(r10 - 128) = r1; \
r1 = *(u8 *)(r10 - 8 ); \
r0 += r1; \
r1 = *(u8 *)(r10 - 11); \
r1 = *(u8 *)(r10 - 13); \
r1 = *(u8 *)(r10 - 15); \
r1 = *(u16*)(r10 - 16); \
r1 = *(u32*)(r10 - 32); \
r1 = *(u64*)(r10 - 64); \
/* read from a spill of a wrong size, it is a separate \
* branch in check_stack_read_fixed_off() \
*/ \
*(u32*)(r10 - 72) = r1; \
r1 = *(u64*)(r10 - 72); \
r0 = 0; \
exit; \
"
::: __clobber_all);
}
/* Read an uninitialized value from stack at a variable offset */
SEC("socket")
__naked int read_uninit_stack_var_off(void *ctx)
{
asm volatile (" \
call %[bpf_get_prandom_u32]; \
/* force stack depth to be 64 */ \
*(u64*)(r10 - 64) = r0; \
r0 = -r0; \
/* give r0 a range [-31, -1] */ \
if r0 s<= -32 goto exit_%=; \
if r0 s>= 0 goto exit_%=; \
/* access stack using r0 */ \
r1 = r10; \
r1 += r0; \
r2 = *(u8*)(r1 + 0); \
exit_%=: r0 = 0; \
exit; \
"
:
: __imm(bpf_get_prandom_u32)
: __clobber_all);
}
static __noinline void dummy(void) {}
/* Pass a pointer to uninitialized stack memory to a helper.
* Passed memory block should be marked as STACK_MISC after helper call.
*/
SEC("socket")
__log_level(7) __msg("fp-104=mmmmmmmm")
__naked int helper_uninit_to_misc(void *ctx)
{
asm volatile (" \
/* force stack depth to be 128 */ \
*(u64*)(r10 - 128) = r1; \
r1 = r10; \
r1 += -128; \
r2 = 32; \
call %[bpf_trace_printk]; \
/* Call to dummy() forces print_verifier_state(..., true), \
* thus showing the stack state, matched by __msg(). \
*/ \
call %[dummy]; \
r0 = 0; \
exit; \
"
:
: __imm(bpf_trace_printk),
__imm(dummy)
: __clobber_all);
}
char _license[] SEC("license") = "GPL";
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