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selftests/bpf: verifier/var_off.c converted to inline assembly
Test verifier/var_off.c automatically converted to use inline assembly. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20230325025524.144043-41-eddyz87@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Eduard Zingerman
Alexei Starovoitov
parent
d330528617
commit
d15f5b68b6
@ -37,6 +37,7 @@
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#include "verifier_value_adj_spill.skel.h"
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#include "verifier_value.skel.h"
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#include "verifier_value_or_null.skel.h"
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#include "verifier_var_off.skel.h"
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__maybe_unused
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static void run_tests_aux(const char *skel_name, skel_elf_bytes_fn elf_bytes_factory)
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@ -96,3 +97,4 @@ void test_verifier_uninit(void) { RUN(verifier_uninit); }
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void test_verifier_value_adj_spill(void) { RUN(verifier_value_adj_spill); }
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void test_verifier_value(void) { RUN(verifier_value); }
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void test_verifier_value_or_null(void) { RUN(verifier_value_or_null); }
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void test_verifier_var_off(void) { RUN(verifier_var_off); }
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349
tools/testing/selftests/bpf/progs/verifier_var_off.c
Normal file
349
tools/testing/selftests/bpf/progs/verifier_var_off.c
Normal file
@ -0,0 +1,349 @@
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// SPDX-License-Identifier: GPL-2.0
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/* Converted from tools/testing/selftests/bpf/verifier/var_off.c */
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 1);
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__type(key, long long);
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__type(value, long long);
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} map_hash_8b SEC(".maps");
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SEC("lwt_in")
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__description("variable-offset ctx access")
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__failure __msg("variable ctx access var_off=(0x0; 0x4)")
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__naked void variable_offset_ctx_access(void)
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{
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asm volatile (" \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned */ \
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r2 &= 4; \
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/* add it to skb. We now have either &skb->len or\
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* &skb->pkt_type, but we don't know which \
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*/ \
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r1 += r2; \
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/* dereference it */ \
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r0 = *(u32*)(r1 + 0); \
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exit; \
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" ::: __clobber_all);
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}
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SEC("cgroup/skb")
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__description("variable-offset stack read, priv vs unpriv")
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__success __failure_unpriv
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__msg_unpriv("R2 variable stack access prohibited for !root")
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__retval(0)
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__naked void stack_read_priv_vs_unpriv(void)
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{
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asm volatile (" \
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/* Fill the top 8 bytes of the stack */ \
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r0 = 0; \
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*(u64*)(r10 - 8) = r0; \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned */ \
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r2 &= 4; \
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r2 -= 8; \
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/* add it to fp. We now have either fp-4 or fp-8, but\
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* we don't know which \
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*/ \
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r2 += r10; \
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/* dereference it for a stack read */ \
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r0 = *(u32*)(r2 + 0); \
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r0 = 0; \
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exit; \
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" ::: __clobber_all);
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}
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SEC("lwt_in")
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__description("variable-offset stack read, uninitialized")
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__failure __msg("invalid variable-offset read from stack R2")
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__naked void variable_offset_stack_read_uninitialized(void)
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{
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asm volatile (" \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned */ \
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r2 &= 4; \
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r2 -= 8; \
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/* add it to fp. We now have either fp-4 or fp-8, but\
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* we don't know which \
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*/ \
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r2 += r10; \
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/* dereference it for a stack read */ \
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r0 = *(u32*)(r2 + 0); \
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r0 = 0; \
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exit; \
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" ::: __clobber_all);
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}
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SEC("socket")
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__description("variable-offset stack write, priv vs unpriv")
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__success __failure_unpriv
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/* Variable stack access is rejected for unprivileged.
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*/
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__msg_unpriv("R2 variable stack access prohibited for !root")
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__retval(0)
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__naked void stack_write_priv_vs_unpriv(void)
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{
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asm volatile (" \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 8-byte aligned */ \
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r2 &= 8; \
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r2 -= 16; \
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/* Add it to fp. We now have either fp-8 or fp-16, but\
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* we don't know which \
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*/ \
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r2 += r10; \
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/* Dereference it for a stack write */ \
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r0 = 0; \
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*(u64*)(r2 + 0) = r0; \
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/* Now read from the address we just wrote. This shows\
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* that, after a variable-offset write, a priviledged\
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* program can read the slots that were in the range of\
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* that write (even if the verifier doesn't actually know\
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* if the slot being read was really written to or not.\
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*/ \
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r3 = *(u64*)(r2 + 0); \
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r0 = 0; \
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exit; \
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" ::: __clobber_all);
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}
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SEC("socket")
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__description("variable-offset stack write clobbers spilled regs")
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__failure
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/* In the priviledged case, dereferencing a spilled-and-then-filled
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* register is rejected because the previous variable offset stack
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* write might have overwritten the spilled pointer (i.e. we lose track
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* of the spilled register when we analyze the write).
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*/
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__msg("R2 invalid mem access 'scalar'")
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__failure_unpriv
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/* The unprivileged case is not too interesting; variable
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* stack access is rejected.
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*/
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__msg_unpriv("R2 variable stack access prohibited for !root")
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__naked void stack_write_clobbers_spilled_regs(void)
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{
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asm volatile (" \
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/* Dummy instruction; needed because we need to patch the next one\
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* and we can't patch the first instruction. \
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*/ \
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r6 = 0; \
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/* Make R0 a map ptr */ \
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r0 = %[map_hash_8b] ll; \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 8-byte aligned */ \
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r2 &= 8; \
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r2 -= 16; \
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/* Add it to fp. We now have either fp-8 or fp-16, but\
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* we don't know which. \
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*/ \
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r2 += r10; \
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/* Spill R0(map ptr) into stack */ \
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*(u64*)(r10 - 8) = r0; \
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/* Dereference the unknown value for a stack write */\
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r0 = 0; \
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*(u64*)(r2 + 0) = r0; \
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/* Fill the register back into R2 */ \
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r2 = *(u64*)(r10 - 8); \
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/* Try to dereference R2 for a memory load */ \
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r0 = *(u64*)(r2 + 8); \
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exit; \
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" :
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: __imm_addr(map_hash_8b)
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: __clobber_all);
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}
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SEC("sockops")
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__description("indirect variable-offset stack access, unbounded")
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__failure __msg("invalid unbounded variable-offset indirect access to stack R4")
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__naked void variable_offset_stack_access_unbounded(void)
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{
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asm volatile (" \
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r2 = 6; \
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r3 = 28; \
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/* Fill the top 16 bytes of the stack. */ \
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r4 = 0; \
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*(u64*)(r10 - 16) = r4; \
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r4 = 0; \
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*(u64*)(r10 - 8) = r4; \
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/* Get an unknown value. */ \
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r4 = *(u64*)(r1 + %[bpf_sock_ops_bytes_received]);\
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/* Check the lower bound but don't check the upper one. */\
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if r4 s< 0 goto l0_%=; \
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/* Point the lower bound to initialized stack. Offset is now in range\
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* from fp-16 to fp+0x7fffffffffffffef, i.e. max value is unbounded.\
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*/ \
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r4 -= 16; \
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r4 += r10; \
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r5 = 8; \
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/* Dereference it indirectly. */ \
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call %[bpf_getsockopt]; \
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l0_%=: r0 = 0; \
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exit; \
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" :
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: __imm(bpf_getsockopt),
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__imm_const(bpf_sock_ops_bytes_received, offsetof(struct bpf_sock_ops, bytes_received))
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: __clobber_all);
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}
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SEC("lwt_in")
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__description("indirect variable-offset stack access, max out of bound")
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__failure __msg("invalid variable-offset indirect access to stack R2")
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__naked void access_max_out_of_bound(void)
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{
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asm volatile (" \
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/* Fill the top 8 bytes of the stack */ \
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r2 = 0; \
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*(u64*)(r10 - 8) = r2; \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned */ \
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r2 &= 4; \
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r2 -= 8; \
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/* add it to fp. We now have either fp-4 or fp-8, but\
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* we don't know which \
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*/ \
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r2 += r10; \
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/* dereference it indirectly */ \
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r1 = %[map_hash_8b] ll; \
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call %[bpf_map_lookup_elem]; \
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r0 = 0; \
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exit; \
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" :
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: __imm(bpf_map_lookup_elem),
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__imm_addr(map_hash_8b)
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: __clobber_all);
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}
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SEC("lwt_in")
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__description("indirect variable-offset stack access, min out of bound")
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__failure __msg("invalid variable-offset indirect access to stack R2")
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__naked void access_min_out_of_bound(void)
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{
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asm volatile (" \
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/* Fill the top 8 bytes of the stack */ \
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r2 = 0; \
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*(u64*)(r10 - 8) = r2; \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned */ \
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r2 &= 4; \
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r2 -= 516; \
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/* add it to fp. We now have either fp-516 or fp-512, but\
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* we don't know which \
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*/ \
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r2 += r10; \
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/* dereference it indirectly */ \
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r1 = %[map_hash_8b] ll; \
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call %[bpf_map_lookup_elem]; \
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r0 = 0; \
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exit; \
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" :
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: __imm(bpf_map_lookup_elem),
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__imm_addr(map_hash_8b)
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: __clobber_all);
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}
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SEC("lwt_in")
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__description("indirect variable-offset stack access, min_off < min_initialized")
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__failure __msg("invalid indirect read from stack R2 var_off")
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__naked void access_min_off_min_initialized(void)
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{
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asm volatile (" \
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/* Fill only the top 8 bytes of the stack. */ \
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r2 = 0; \
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*(u64*)(r10 - 8) = r2; \
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/* Get an unknown value */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned. */ \
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r2 &= 4; \
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r2 -= 16; \
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/* Add it to fp. We now have either fp-12 or fp-16, but we don't know\
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* which. fp-16 size 8 is partially uninitialized stack.\
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*/ \
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r2 += r10; \
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/* Dereference it indirectly. */ \
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r1 = %[map_hash_8b] ll; \
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call %[bpf_map_lookup_elem]; \
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r0 = 0; \
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exit; \
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" :
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: __imm(bpf_map_lookup_elem),
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__imm_addr(map_hash_8b)
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: __clobber_all);
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}
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SEC("cgroup/skb")
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__description("indirect variable-offset stack access, priv vs unpriv")
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__success __failure_unpriv
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__msg_unpriv("R2 variable stack access prohibited for !root")
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__retval(0)
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__naked void stack_access_priv_vs_unpriv(void)
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{
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asm volatile (" \
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/* Fill the top 16 bytes of the stack. */ \
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r2 = 0; \
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*(u64*)(r10 - 16) = r2; \
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r2 = 0; \
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*(u64*)(r10 - 8) = r2; \
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/* Get an unknown value. */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned. */ \
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r2 &= 4; \
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r2 -= 16; \
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/* Add it to fp. We now have either fp-12 or fp-16, we don't know\
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* which, but either way it points to initialized stack.\
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*/ \
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r2 += r10; \
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/* Dereference it indirectly. */ \
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r1 = %[map_hash_8b] ll; \
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call %[bpf_map_lookup_elem]; \
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r0 = 0; \
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exit; \
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" :
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: __imm(bpf_map_lookup_elem),
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__imm_addr(map_hash_8b)
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: __clobber_all);
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}
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SEC("lwt_in")
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__description("indirect variable-offset stack access, ok")
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__success __retval(0)
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__naked void variable_offset_stack_access_ok(void)
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{
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asm volatile (" \
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/* Fill the top 16 bytes of the stack. */ \
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r2 = 0; \
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*(u64*)(r10 - 16) = r2; \
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r2 = 0; \
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*(u64*)(r10 - 8) = r2; \
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/* Get an unknown value. */ \
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r2 = *(u32*)(r1 + 0); \
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/* Make it small and 4-byte aligned. */ \
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r2 &= 4; \
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r2 -= 16; \
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/* Add it to fp. We now have either fp-12 or fp-16, we don't know\
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* which, but either way it points to initialized stack.\
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*/ \
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r2 += r10; \
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/* Dereference it indirectly. */ \
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r1 = %[map_hash_8b] ll; \
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call %[bpf_map_lookup_elem]; \
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r0 = 0; \
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exit; \
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" :
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: __imm(bpf_map_lookup_elem),
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__imm_addr(map_hash_8b)
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: __clobber_all);
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}
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char _license[] SEC("license") = "GPL";
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@ -1,291 +0,0 @@
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{
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"variable-offset ctx access",
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.insns = {
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/* Get an unknown value */
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BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
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/* Make it small and 4-byte aligned */
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BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
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/* add it to skb. We now have either &skb->len or
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* &skb->pkt_type, but we don't know which
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*/
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BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_2),
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/* dereference it */
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 0),
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BPF_EXIT_INSN(),
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},
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.errstr = "variable ctx access var_off=(0x0; 0x4)",
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.result = REJECT,
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.prog_type = BPF_PROG_TYPE_LWT_IN,
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},
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{
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"variable-offset stack read, priv vs unpriv",
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.insns = {
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/* Fill the top 8 bytes of the stack */
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BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
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/* Get an unknown value */
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BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
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/* Make it small and 4-byte aligned */
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BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
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BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
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/* add it to fp. We now have either fp-4 or fp-8, but
|
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* we don't know which
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*/
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BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
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/* dereference it for a stack read */
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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.result_unpriv = REJECT,
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.errstr_unpriv = "R2 variable stack access prohibited for !root",
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"variable-offset stack read, uninitialized",
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.insns = {
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/* Get an unknown value */
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BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
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/* Make it small and 4-byte aligned */
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BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
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BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
|
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/* add it to fp. We now have either fp-4 or fp-8, but
|
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* we don't know which
|
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*/
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BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
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/* dereference it for a stack read */
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_2, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
|
||||
.result = REJECT,
|
||||
.errstr = "invalid variable-offset read from stack R2",
|
||||
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||||
},
|
||||
{
|
||||
"variable-offset stack write, priv vs unpriv",
|
||||
.insns = {
|
||||
/* Get an unknown value */
|
||||
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||||
/* Make it small and 8-byte aligned */
|
||||
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 8),
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||||
/* Add it to fp. We now have either fp-8 or fp-16, but
|
||||
* we don't know which
|
||||
*/
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||||
/* Dereference it for a stack write */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
|
||||
/* Now read from the address we just wrote. This shows
|
||||
* that, after a variable-offset write, a priviledged
|
||||
* program can read the slots that were in the range of
|
||||
* that write (even if the verifier doesn't actually know
|
||||
* if the slot being read was really written to or not.
|
||||
*/
|
||||
BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_2, 0),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
/* Variable stack access is rejected for unprivileged.
|
||||
*/
|
||||
.errstr_unpriv = "R2 variable stack access prohibited for !root",
|
||||
.result_unpriv = REJECT,
|
||||
.result = ACCEPT,
|
||||
},
|
||||
{
|
||||
"variable-offset stack write clobbers spilled regs",
|
||||
.insns = {
|
||||
/* Dummy instruction; needed because we need to patch the next one
|
||||
* and we can't patch the first instruction.
|
||||
*/
|
||||
BPF_MOV64_IMM(BPF_REG_6, 0),
|
||||
/* Make R0 a map ptr */
|
||||
BPF_LD_MAP_FD(BPF_REG_0, 0),
|
||||
/* Get an unknown value */
|
||||
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||||
/* Make it small and 8-byte aligned */
|
||||
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 8),
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||||
/* Add it to fp. We now have either fp-8 or fp-16, but
|
||||
* we don't know which.
|
||||
*/
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||||
/* Spill R0(map ptr) into stack */
|
||||
BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
|
||||
/* Dereference the unknown value for a stack write */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
|
||||
/* Fill the register back into R2 */
|
||||
BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -8),
|
||||
/* Try to dereference R2 for a memory load */
|
||||
BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 8),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.fixup_map_hash_8b = { 1 },
|
||||
/* The unprivileged case is not too interesting; variable
|
||||
* stack access is rejected.
|
||||
*/
|
||||
.errstr_unpriv = "R2 variable stack access prohibited for !root",
|
||||
.result_unpriv = REJECT,
|
||||
/* In the priviledged case, dereferencing a spilled-and-then-filled
|
||||
* register is rejected because the previous variable offset stack
|
||||
* write might have overwritten the spilled pointer (i.e. we lose track
|
||||
* of the spilled register when we analyze the write).
|
||||
*/
|
||||
.errstr = "R2 invalid mem access 'scalar'",
|
||||
.result = REJECT,
|
||||
},
|
||||
{
|
||||
"indirect variable-offset stack access, unbounded",
|
||||
.insns = {
|
||||
BPF_MOV64_IMM(BPF_REG_2, 6),
|
||||
BPF_MOV64_IMM(BPF_REG_3, 28),
|
||||
/* Fill the top 16 bytes of the stack. */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||||
/* Get an unknown value. */
|
||||
BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_1, offsetof(struct bpf_sock_ops,
|
||||
bytes_received)),
|
||||
/* Check the lower bound but don't check the upper one. */
|
||||
BPF_JMP_IMM(BPF_JSLT, BPF_REG_4, 0, 4),
|
||||
/* Point the lower bound to initialized stack. Offset is now in range
|
||||
* from fp-16 to fp+0x7fffffffffffffef, i.e. max value is unbounded.
|
||||
*/
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_4, 16),
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_4, BPF_REG_10),
|
||||
BPF_MOV64_IMM(BPF_REG_5, 8),
|
||||
/* Dereference it indirectly. */
|
||||
BPF_EMIT_CALL(BPF_FUNC_getsockopt),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.errstr = "invalid unbounded variable-offset indirect access to stack R4",
|
||||
.result = REJECT,
|
||||
.prog_type = BPF_PROG_TYPE_SOCK_OPS,
|
||||
},
|
||||
{
|
||||
"indirect variable-offset stack access, max out of bound",
|
||||
.insns = {
|
||||
/* Fill the top 8 bytes of the stack */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||||
/* Get an unknown value */
|
||||
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||||
/* Make it small and 4-byte aligned */
|
||||
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 8),
|
||||
/* add it to fp. We now have either fp-4 or fp-8, but
|
||||
* we don't know which
|
||||
*/
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||||
/* dereference it indirectly */
|
||||
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||||
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.fixup_map_hash_8b = { 5 },
|
||||
.errstr = "invalid variable-offset indirect access to stack R2",
|
||||
.result = REJECT,
|
||||
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||||
},
|
||||
{
|
||||
"indirect variable-offset stack access, min out of bound",
|
||||
.insns = {
|
||||
/* Fill the top 8 bytes of the stack */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||||
/* Get an unknown value */
|
||||
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||||
/* Make it small and 4-byte aligned */
|
||||
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 516),
|
||||
/* add it to fp. We now have either fp-516 or fp-512, but
|
||||
* we don't know which
|
||||
*/
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||||
/* dereference it indirectly */
|
||||
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||||
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.fixup_map_hash_8b = { 5 },
|
||||
.errstr = "invalid variable-offset indirect access to stack R2",
|
||||
.result = REJECT,
|
||||
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||||
},
|
||||
{
|
||||
"indirect variable-offset stack access, min_off < min_initialized",
|
||||
.insns = {
|
||||
/* Fill only the top 8 bytes of the stack. */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||||
/* Get an unknown value */
|
||||
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||||
/* Make it small and 4-byte aligned. */
|
||||
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||||
/* Add it to fp. We now have either fp-12 or fp-16, but we don't know
|
||||
* which. fp-16 size 8 is partially uninitialized stack.
|
||||
*/
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||||
/* Dereference it indirectly. */
|
||||
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||||
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.fixup_map_hash_8b = { 5 },
|
||||
.errstr = "invalid indirect read from stack R2 var_off",
|
||||
.result = REJECT,
|
||||
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||||
},
|
||||
{
|
||||
"indirect variable-offset stack access, priv vs unpriv",
|
||||
.insns = {
|
||||
/* Fill the top 16 bytes of the stack. */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||||
/* Get an unknown value. */
|
||||
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||||
/* Make it small and 4-byte aligned. */
|
||||
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||||
/* Add it to fp. We now have either fp-12 or fp-16, we don't know
|
||||
* which, but either way it points to initialized stack.
|
||||
*/
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||||
/* Dereference it indirectly. */
|
||||
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||||
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.fixup_map_hash_8b = { 6 },
|
||||
.errstr_unpriv = "R2 variable stack access prohibited for !root",
|
||||
.result_unpriv = REJECT,
|
||||
.result = ACCEPT,
|
||||
.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
|
||||
},
|
||||
{
|
||||
"indirect variable-offset stack access, ok",
|
||||
.insns = {
|
||||
/* Fill the top 16 bytes of the stack. */
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
|
||||
BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
|
||||
/* Get an unknown value. */
|
||||
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
|
||||
/* Make it small and 4-byte aligned. */
|
||||
BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 4),
|
||||
BPF_ALU64_IMM(BPF_SUB, BPF_REG_2, 16),
|
||||
/* Add it to fp. We now have either fp-12 or fp-16, we don't know
|
||||
* which, but either way it points to initialized stack.
|
||||
*/
|
||||
BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_10),
|
||||
/* Dereference it indirectly. */
|
||||
BPF_LD_MAP_FD(BPF_REG_1, 0),
|
||||
BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
|
||||
BPF_MOV64_IMM(BPF_REG_0, 0),
|
||||
BPF_EXIT_INSN(),
|
||||
},
|
||||
.fixup_map_hash_8b = { 6 },
|
||||
.result = ACCEPT,
|
||||
.prog_type = BPF_PROG_TYPE_LWT_IN,
|
||||
},
|
||||
Loading…
Reference in New Issue
Block a user