| Message ID | 20211011162533.53404-23-cgzones@googlemail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | libsepol: add fuzzer for reading binary policies | expand |
On Mon, Oct 11, 2021 at 12:41 PM Christian Göttsche <cgzones@googlemail.com> wrote: > > Check a class has not more than the supported 32 permissions. > > ==28413==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f74ec3341a3 bp 0x7ffd0b7e5030 sp 0x7ffd0b7e47e8 T0) > ==28413==The signal is caused by a READ memory access. > ==28413==Hint: address points to the zero page. > #0 0x7f74ec3341a3 string/../sysdeps/x86_64/multiarch/../strchr.S:32 > #1 0x4bfc78 in strchr (./out/binpolicy-fuzzer+0x4bfc78) > #2 0x55b7f2 in class_constraint_rules_to_strs ./libsepol/src/kernel_to_conf.c:288:7 > #3 0x55b7f2 in constraint_rules_to_strs ./libsepol/src/kernel_to_conf.c:364:9 > #4 0x55ac80 in sepol_kernel_policydb_to_conf ./libsepol/src/kernel_to_conf.c:3071:7 > #5 0x55a34f in LLVMFuzzerTestOneInput ./libsepol/fuzz/binpolicy-fuzzer.c:38:9 > #6 0x45aed3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) fuzzer.o > #7 0x446a12 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) fuzzer.o > #8 0x44c93b in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) fuzzer.o > #9 0x475dd2 in main (./out/binpolicy-fuzzer+0x475dd2) > #10 0x7f74ec2be7ec in __libc_start_main csu/../csu/libc-start.c:332:16 > #11 0x423689 in _start (./out/binpolicy-fuzzer+0x423689) > > Signed-off-by: Christian Göttsche <cgzones@googlemail.com> > --- > libsepol/src/policydb_validate.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c > index c9700399..7ec0675c 100644 > --- a/libsepol/src/policydb_validate.c > +++ b/libsepol/src/policydb_validate.c > @@ -203,6 +203,8 @@ static int validate_class_datum(sepol_handle_t *handle, class_datum_t *class, va > goto bad; > if (validate_constraint_nodes(handle, class->validatetrans, flavors)) > goto bad; > + if (class->permissions.nprim > PERM_SYMTAB_SIZE) > + goto bad; > This is good, but it also needs to be done for commons. See comments for patch 13. Thanks, Jim > return 0; > > -- > 2.33.0 >
diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c index c9700399..7ec0675c 100644 --- a/libsepol/src/policydb_validate.c +++ b/libsepol/src/policydb_validate.c @@ -203,6 +203,8 @@ static int validate_class_datum(sepol_handle_t *handle, class_datum_t *class, va goto bad; if (validate_constraint_nodes(handle, class->validatetrans, flavors)) goto bad; + if (class->permissions.nprim > PERM_SYMTAB_SIZE) + goto bad; return 0;
Check a class has not more than the supported 32 permissions. ==28413==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f74ec3341a3 bp 0x7ffd0b7e5030 sp 0x7ffd0b7e47e8 T0) ==28413==The signal is caused by a READ memory access. ==28413==Hint: address points to the zero page. #0 0x7f74ec3341a3 string/../sysdeps/x86_64/multiarch/../strchr.S:32 #1 0x4bfc78 in strchr (./out/binpolicy-fuzzer+0x4bfc78) #2 0x55b7f2 in class_constraint_rules_to_strs ./libsepol/src/kernel_to_conf.c:288:7 #3 0x55b7f2 in constraint_rules_to_strs ./libsepol/src/kernel_to_conf.c:364:9 #4 0x55ac80 in sepol_kernel_policydb_to_conf ./libsepol/src/kernel_to_conf.c:3071:7 #5 0x55a34f in LLVMFuzzerTestOneInput ./libsepol/fuzz/binpolicy-fuzzer.c:38:9 #6 0x45aed3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) fuzzer.o #7 0x446a12 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) fuzzer.o #8 0x44c93b in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) fuzzer.o #9 0x475dd2 in main (./out/binpolicy-fuzzer+0x475dd2) #10 0x7f74ec2be7ec in __libc_start_main csu/../csu/libc-start.c:332:16 #11 0x423689 in _start (./out/binpolicy-fuzzer+0x423689) Signed-off-by: Christian Göttsche <cgzones@googlemail.com> --- libsepol/src/policydb_validate.c | 2 ++ 1 file changed, 2 insertions(+)