The `next` member might be checked against NULL and dereferenced before
it gets assigned, due to jumps from failure gotos to the cleanup
section.
==31017==ERROR: AddressSanitizer: SEGV on unknown address (pc 0x000000579654 bp 0x7ffd3a07d110 sp 0x7ffd3a07d000 T0)
==31017==The signal is caused by a READ memory access.
==31017==Hint: this fault was caused by a dereference of a high value address (see register values below). Disassemble the provided pc to learn which register was used.
#0 0x579654 in filename_trans_read_one ./libsepol/src/policydb.c:2874:55
#1 0x579654 in filename_trans_read ./libsepol/src/policydb.c:2902:9
#2 0x5771b7 in policydb_read ./libsepol/src/policydb.c:4509:7
#3 0x55a1f5 in LLVMFuzzerTestOneInput ./libsepol/fuzz/binpolicy-fuzzer.c:24:6
#4 0x45aed3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) fuzzer.o
#5 0x446a12 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) fuzzer.o
#6 0x44c93b in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) fuzzer.o
#7 0x475dd2 in main (./out/binpolicy-fuzzer+0x475dd2)
#8 0x7f2a4e7f97ec in __libc_start_main csu/../csu/libc-start.c:332:16
#9 0x423689 in _start (./out/binpolicy-fuzzer+0x423689)
Signed-off-by: Christian Göttsche <cgzones@xxxxxxxxxxxxxx>
---
libsepol/src/policydb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
index 25ffa07c..79aba3af 100644
--- a/libsepol/src/policydb.c
+++ b/libsepol/src/policydb.c
@@ -2780,6 +2780,7 @@ static int filename_trans_read_one(policydb_t *p, struct policy_file *fp)
if (!datum)
goto err;
+ datum->next = NULL;
*dst = datum;
/* ebitmap_read() will at least init the bitmap */
@@ -2797,7 +2798,6 @@ static int filename_trans_read_one(policydb_t *p, struct policy_file *fp)
dst = &datum->next;
}
- *dst = NULL;
if (ndatum > 1 && filename_trans_check_datum(first))
goto err;
--
2.34.1
