From eb141ba81158feb74118da4e7a3f2266b11ffe10 Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>

Date: Mon, 9 Jul 2018 08:06:28 +0200

Subject: [PATCH] sd-bus: unify three code-paths which free struct

 bus_container

We didn't free one of the fields in two of the places.

$ valgrind --show-leak-kinds=all --leak-check=full \

  build/fuzz-bus-message \

  test/fuzz/fuzz-bus-message/leak-c09c0e2256d43bc5e2d02748c8d8760e7bc25d20

...

==14457== HEAP SUMMARY:

==14457==     in use at exit: 3 bytes in 1 blocks

==14457==   total heap usage: 509 allocs, 508 frees, 51,016 bytes allocated

==14457==

==14457== 3 bytes in 1 blocks are definitely lost in loss record 1 of 1

==14457==    at 0x4C2EBAB: malloc (vg_replace_malloc.c:299)

==14457==    by 0x53AFE79: strndup (in /usr/lib64/libc-2.27.so)

==14457==    by 0x4F52EB8: free_and_strndup (string-util.c:1039)

==14457==    by 0x4F8E1AB: sd_bus_message_peek_type (bus-message.c:4193)

==14457==    by 0x4F76CB5: bus_message_dump (bus-dump.c:144)

==14457==    by 0x108F12: LLVMFuzzerTestOneInput (fuzz-bus-message.c:24)

==14457==    by 0x1090F7: main (fuzz-main.c:34)

==14457==

==14457== LEAK SUMMARY:

==14457==    definitely lost: 3 bytes in 1 blocks

(cherry picked from commit 6d1e0f4fcba8d6f425da3dc91805db95399b3c8b)

Resolves: #1635435

---

 src/libsystemd/sd-bus/bus-message.c           |  64 +++++++++---------

 ...k-c09c0e2256d43bc5e2d02748c8d8760e7bc25d20 | Bin 0 -> 534 bytes

 2 files changed, 32 insertions(+), 32 deletions(-)

 create mode 100644 test/fuzz/fuzz-bus-message/leak-c09c0e2256d43bc5e2d02748c8d8760e7bc25d20

diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c

index 7c8bad2bdd..d55cb14843 100644

--- a/src/libsystemd/sd-bus/bus-message.c

+++ b/src/libsystemd/sd-bus/bus-message.c

@@ -77,19 +77,38 @@ static void message_reset_parts(sd_bus_message *m) {

         m->cached_rindex_part_begin = 0;

 }

-static void message_reset_containers(sd_bus_message *m) {

-        unsigned i;

+static struct bus_container *message_get_container(sd_bus_message *m) {

+        assert(m);

+

+        if (m->n_containers == 0)

+                return &m->root_container;

+

+        assert(m->containers);

+        return m->containers + m->n_containers - 1;

+}

+

+static void message_free_last_container(sd_bus_message *m) {

+        struct bus_container *c;

+

+        c = message_get_container(m);

+

+        free(c->signature);

+        free(c->peeked_signature);

+        free(c->offsets);

+

+        /* Move to previous container, but not if we are on root container */

+        if (m->n_containers > 0)

+                m->n_containers--;

+}

+static void message_reset_containers(sd_bus_message *m) {

         assert(m);

-        for (i = 0; i < m->n_containers; i++) {

-                free(m->containers[i].signature);

-                free(m->containers[i].offsets);

-        }

+        while (m->n_containers > 0)

+                message_free_last_container(m);

         m->containers = mfree(m->containers);

-

-        m->n_containers = m->containers_allocated = 0;

+        m->containers_allocated = 0;

         m->root_container.index = 0;

 }

@@ -112,10 +131,8 @@ static sd_bus_message* message_free(sd_bus_message *m) {

                 free(m->iovec);

         message_reset_containers(m);

-        free(m->root_container.signature);

-        free(m->root_container.offsets);

-

-        free(m->root_container.peeked_signature);

+        assert(m->n_containers == 0);

+        message_free_last_container(m);

         bus_creds_done(&m->creds);

         return mfree(m);

@@ -1113,16 +1130,6 @@ _public_ int sd_bus_message_set_allow_interactive_authorization(sd_bus_message *

         return 0;

 }

-static struct bus_container *message_get_container(sd_bus_message *m) {

-        assert(m);

-

-        if (m->n_containers == 0)

-                return &m->root_container;

-

-        assert(m->containers);

-        return m->containers + m->n_containers - 1;

-}

-

 struct bus_body_part *message_append_part(sd_bus_message *m) {

         struct bus_body_part *part;

@@ -4108,13 +4115,9 @@ _public_ int sd_bus_message_exit_container(sd_bus_message *m) {

                         return -EBUSY;

         }

-        free(c->signature);

-        free(c->peeked_signature);

-        free(c->offsets);

-        m->n_containers--;

+        message_free_last_container(m);

         c = message_get_container(m);

-

         saved = c->index;

         c->index = c->saved_index;

         r = container_next_item(m, c, &m->rindex);

@@ -4132,16 +4135,13 @@ static void message_quit_container(sd_bus_message *m) {

         assert(m->sealed);

         assert(m->n_containers > 0);

-        c = message_get_container(m);

-

         /* Undo seeks */

+        c = message_get_container(m);

         assert(m->rindex >= c->before);

         m->rindex = c->before;

         /* Free container */

-        free(c->signature);

-        free(c->offsets);

-        m->n_containers--;

+        message_free_last_container(m);

         /* Correct index of new top-level container */

         c = message_get_container(m);

diff --git a/test/fuzz/fuzz-bus-message/leak-c09c0e2256d43bc5e2d02748c8d8760e7bc25d20 b/test/fuzz/fuzz-bus-message/leak-c09c0e2256d43bc5e2d02748c8d8760e7bc25d20

new file mode 100644

index 0000000000000000000000000000000000000000..c371824ffb604708619fd0713e8fca609bac18f7

GIT binary patch

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