==91274==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f60b0afe8c6 bp 0x7ffd42edc990 sp 0x7ffd42edc148 T0)
==91274==The signal is caused by a READ memory access.
==91274==Hint: address points to the zero page.
#0 0x7f60b0afe8c6 string/../sysdeps/x86_64/multiarch/../strlen.S:120
#1 0x4bd128 in __interceptor_strlen (./out/binpolicy-fuzzer+0x4bd128)
#2 0x5eb387 in create_str_helper ./libsepol/src/kernel_to_common.c:69:10
#3 0x5eb11e in create_str ./libsepol/src/kernel_to_common.c:99:8
#4 0x56ad7b in context_to_str ./libsepol/src/kernel_to_conf.c:2408:9
#5 0x56a717 in write_sid_context_rules_to_conf ./libsepol/src/kernel_to_conf.c:2441:9
#6 0x55b26c in write_selinux_isid_rules_to_conf ./libsepol/src/kernel_to_conf.c:2476:9
#7 0x55b26c in sepol_kernel_policydb_to_conf ./libsepol/src/kernel_to_conf.c:3206:8
#8 0x55a34f in LLVMFuzzerTestOneInput ./libsepol/fuzz/binpolicy-fuzzer.c:38:9
#9 0x45aed3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) fuzzer.o
#10 0x446a12 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) fuzzer.o
#11 0x44c93b in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) fuzzer.o
#12 0x475dd2 in main (./out/binpolicy-fuzzer+0x475dd2)
#13 0x7f60b0a887ec in __libc_start_main csu/../csu/libc-start.c:332:16
#14 0x423689 in _start (./out/binpolicy-fuzzer+0x423689)
Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
---
libsepol/src/policydb_validate.c | 37 ++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c
index 9134e541..5c06e6f4 100644
--- a/libsepol/src/policydb_validate.c
+++ b/libsepol/src/policydb_validate.c
@@ -677,6 +677,41 @@ static int validate_filename_trans_hashtab(sepol_handle_t *handle, hashtab_t fil
return 0;
}
+static int validate_context(context_struct_t *con, validate_t flavors[], int mls)
+{
+ if (validate_value(con->user, &flavors[SYM_USERS]))
+ return -1;
+ if (validate_value(con->role, &flavors[SYM_ROLES]))
+ return -1;
+ if (validate_value(con->type, &flavors[SYM_TYPES]))
+ return -1;
+ if (mls && validate_mls_range(&con->range, &flavors[SYM_LEVELS], &flavors[SYM_CATS]))
+ return -1;
+
+ return 0;
+}
+
+static int validate_ocontexts(sepol_handle_t *handle, policydb_t *p, validate_t flavors[])
+{
+ ocontext_t *octx;
+ unsigned int i;
+
+ for (i = 0; i < OCON_NUM; i++) {
+ for (octx = p->ocontexts[i]; octx; octx = octx->next) {
+ if (validate_context(&octx->context[0], flavors, p->mls))
+ goto bad;
+ if ((i == OCON_FS || i == OCON_NETIF) && validate_context(&octx->context[1], flavors, p->mls))
+ goto bad;
+ }
+ }
+
+ return 0;
+
+bad:
+ ERR(handle, "Invalid ocontext");
+ return -1;
+}
+
/*
* Functions to validate a module policydb
*/
@@ -861,6 +896,8 @@ int validate_policydb(sepol_handle_t *handle, policydb_t *p)
goto bad;
if (validate_role_allows(handle, p->role_allow, flavors))
goto bad;
+ if (validate_ocontexts(handle, p, flavors))
+ goto bad;
if (p->policyvers >= POLICYDB_VERSION_FILENAME_TRANS)
if (validate_filename_trans_hashtab(handle, p->filename_trans, flavors))
goto bad;
--
2.33.0
