Check if the sid value is saturated to guard dependent allocations.
==19967== ERROR: libFuzzer: out-of-memory (malloc(7784628224))
#0 0x52dc61 in __sanitizer_print_stack_trace (./out/binpolicy-fuzzer+0x52dc61)
#1 0x475618 in fuzzer::PrintStackTrace() fuzzer.o
#2 0x458855 in fuzzer::Fuzzer::HandleMalloc(unsigned long) fuzzer.o
#3 0x45876a in fuzzer::MallocHook(void const volatile*, unsigned long) fuzzer.o
#4 0x534557 in __sanitizer::RunMallocHooks(void const*, unsigned long) (./out/binpolicy-fuzzer+0x534557)
#5 0x4aa7d7 in __asan::Allocator::Allocate(unsigned long, unsigned long, __sanitizer::BufferedStackTrace*, __asan::AllocType, bool) (./out/binpolicy-fuzzer+0x4aa7d7)
#6 0x4aabe3 in __asan::Allocator::Reallocate(void*, unsigned long, __sanitizer::BufferedStackTrace*) (./out/binpolicy-fuzzer+0x4aabe3)
#7 0x4aaa32 in __asan::asan_reallocarray(void*, unsigned long, unsigned long, __sanitizer::BufferedStackTrace*) (./out/binpolicy-fuzzer+0x4aaa32)
#8 0x525f8e in __interceptor_reallocarray (./out/binpolicy-fuzzer+0x525f8e)
#9 0x5ebad3 in strs_add_at_index ./libsepol/src/kernel_to_common.c:224:9
#10 0x5680eb in write_sids_to_conf ./libsepol/src/kernel_to_conf.c:466:8
#11 0x55c1c0 in write_sid_decl_rules_to_conf ./libsepol/src/kernel_to_conf.c:498:8
#12 0x55ad36 in sepol_kernel_policydb_to_conf ./libsepol/src/kernel_to_conf.c:3083:7
#13 0x55a34f in LLVMFuzzerTestOneInput ./libsepol/fuzz/binpolicy-fuzzer.c:38:9
#14 0x45aed3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) fuzzer.o
#15 0x446a12 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) fuzzer.o
#16 0x44c93b in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) fuzzer.o
#17 0x475dd2 in main (./out/binpolicy-fuzzer+0x475dd2)
#18 0x7f085ac657ec in __libc_start_main csu/../csu/libc-start.c:332:16
#19 0x423689 in _start (./out/binpolicy-fuzzer+0x423689)
Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
---
libsepol/src/policydb.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
index 5e8b4a3f..51fbd7c8 100644
--- a/libsepol/src/policydb.c
+++ b/libsepol/src/policydb.c
@@ -2921,6 +2921,8 @@ static int ocontext_read_xen(const struct policydb_compat_info *info,
if (rc < 0)
return -1;
c->sid[0] = le32_to_cpu(buf[0]);
+ if (is_saturated(c->sid[0]))
+ return -1;
if (context_read_and_validate
(&c->context[0], p, fp))
return -1;
@@ -3032,6 +3034,8 @@ static int ocontext_read_selinux(const struct policydb_compat_info *info,
if (rc < 0)
return -1;
c->sid[0] = le32_to_cpu(buf[0]);
+ if (is_saturated(c->sid[0]))
+ return -1;
if (context_read_and_validate
(&c->context[0], p, fp))
return -1;
--
2.33.0
