[4/4] checkpolicy: do not leak memory when a class is not found in an avrule

Commit Message

Nicolas Iooss Jan. 21, 2017, 2:26 p.m. UTC

While checkmodule tries to compile the following policy file and fails
because class "process" is not found, it does not free some allocated
memory:

    module ckpol_leaktest 1.0.0;
    require {type TYPE1;}
    allow TYPE1 self:process fork;

clang memory sanitier output is:

Patch

=================================================================
==16050==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 136 byte(s) in 1 object(s) allocated from:
    #0 0x7f8bd8127608 in malloc (/usr/lib/clang/3.9.1/lib/linux/libclang_rt.asan-x86_64.so+0xf6608)
    #1 0x41a620 in define_te_avtab_helper /usr/src/selinux/checkpolicy/policy_define.c:2450:24
    #2 0x41b6c8 in define_te_avtab /usr/src/selinux/checkpolicy/policy_define.c:2621:6
    #3 0x40522b in yyparse /usr/src/selinux/checkpolicy/policy_parse.y:470:10
    #4 0x411816 in read_source_policy /usr/src/selinux/checkpolicy/parse_util.c:64:6
    #5 0x7f8bd7cb3290 in __libc_start_main (/usr/lib/libc.so.6+0x20290)

Direct leak of 8 byte(s) in 1 object(s) allocated from:
    #0 0x7f8bd8127608 in malloc (/usr/lib/clang/3.9.1/lib/linux/libclang_rt.asan-x86_64.so+0xf6608)
    #1 0x411c87 in insert_id /usr/src/selinux/checkpolicy/policy_define.c:120:18

Indirect leak of 24 byte(s) in 1 object(s) allocated from:
    #0 0x7f8bd8127608 in malloc (/usr/lib/clang/3.9.1/lib/linux/libclang_rt.asan-x86_64.so+0xf6608)
    #1 0x43133c in ebitmap_set_bit /usr/src/selinux/libsepol/src/ebitmap.c:321:27

Indirect leak of 18 byte(s) in 1 object(s) allocated from:
    #0 0x7f8bd80b5eb0 in __interceptor___strdup (/usr/lib/clang/3.9.1/lib/linux/libclang_rt.asan-x86_64.so+0x84eb0)
    #1 0x41a6e5 in define_te_avtab_helper /usr/src/selinux/checkpolicy/policy_define.c:2460:28
    #2 0x41b6c8 in define_te_avtab /usr/src/selinux/checkpolicy/policy_define.c:2621:6
    #3 0x40522b in yyparse /usr/src/selinux/checkpolicy/policy_parse.y:470:10
    #4 0x411816 in read_source_policy /usr/src/selinux/checkpolicy/parse_util.c:64:6
    #5 0x7f8bd7cb3290 in __libc_start_main (/usr/lib/libc.so.6+0x20290)

SUMMARY: AddressSanitizer: 186 byte(s) leaked in 4 allocation(s).

Signed-off-by: Nicolas Iooss <[e-mail]>
---
 checkpolicy/policy_define.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/checkpolicy/policy_define.c b/checkpolicy/policy_define.c
index e2e384d4599b..dbafadb01e21 100644
--- a/checkpolicy/policy_define.c
+++ b/checkpolicy/policy_define.c
@@ -348,13 +348,14 @@  static int read_classes(ebitmap_t *e_classes)
 		cladatum = hashtab_search(policydbp->p_classes.table, id);
 		if (!cladatum) {
 			yyerror2("unknown class %s", id);
+			free(id);
 			return -1;
 		}
+		free(id);
 		if (ebitmap_set_bit(e_classes, cladatum->s.value - 1, TRUE)) {
 			yyerror("Out of memory");
 			return -1;
 		}
-		free(id);
 	}
 	return 0;
 }
@@ -2552,6 +2553,10 @@  int define_te_avtab_helper(int which, avrule_t ** rule)
 	*rule = avrule;
 
       out:
+	if (ret) {
+		avrule_destroy(avrule);
+		free(avrule);
+	}
 	return ret;
 
 }