2009-09-26 16:37:58

by Steve Grubb

[permalink] [raw]
Subject: [PATCH] init and extra checking fixups

Hello,

I was doing some code reviews of the 4.54 release and found a couple
things that should be fixed up. This patch is looking at things that may not
have been initialized or is doing value checks that are unnecessary.

In audio/avdtp.c, the avdtp_setconf_cmd function has an exit jump for failed.
There are several calls to the goto that do not set err to something, meaning
that the stack contents are what's used. I set err =0 in the beginning so that
we no longer use the stack contents, but it seems like there should be some
general error code that says we failed for an unspecified reason.

In audio/control.c, the function control_cb takes a variable cond and first
thing it or's G_IO_IN with it and uses the result for a test in an if
statement. I suspect it should be a '&' operator.

In audio/unix.c, the function a2dp_discovery_complete at line 659 has a
variable ca2dp. There is a check at line 661 to see that its not NULL. It can
never be NULL because its position in the unix_client structure will never
let it be NULL. So, this check should be dropped.

In compat/hidd.c, there is a function do_connect with a variable, name. It
could conceivably be uninitialized when used in a strcmp at line 473.

In lib/sdp.c, the function sdp_get_lang_attr has a variable pCode that is
being checked for non-NULL at line 2029. It gets its value from curr_data which
has to be non-NULL to enter the loop. So, checking pCode does nothing. It
should be dropped.

Same file, in the function sdp_service_attr_req there is a variable
rsp_concat_buf. If the allocations for reqbuf or rspbuf fail, it goes to end
where it will attempt to free rsp_concat_buf.data which is whatever the stack
contents are. This same issue pops up again in the function,
sdp_service_search_attr_req a little farther down.

NOT FIXED - In src/sdpd-service.c, the function create_ext_inquiry_response
has a variable uuid that is used at line 223 in an equality test without
having been initialized. No idea what the right code for that is.

In tools/hcitool.c, around line 687, handle could conceivably be used without
being initialized. I set it to 0.

Signed-off-by: Steve Grubb <[email protected]>


diff -urp bluez-4.54.orig/audio/avdtp.c bluez-4.54/audio/avdtp.c
--- bluez-4.54.orig/audio/avdtp.c 2009-09-26 08:43:56.000000000 -0400
+++ bluez-4.54/audio/avdtp.c 2009-09-26 11:17:07.000000000 -0400
@@ -1248,7 +1248,7 @@ static gboolean avdtp_setconf_cmd(struct
struct conf_rej rej;
struct avdtp_local_sep *sep;
struct avdtp_stream *stream;
- uint8_t err, category = 0x00;
+ uint8_t err = 0, category = 0x00;
struct audio_device *dev;
bdaddr_t src, dst;
GSList *l;
diff -urp bluez-4.54.orig/audio/control.c bluez-4.54/audio/control.c
--- bluez-4.54.orig/audio/control.c 2009-09-26 08:43:56.000000000 -0400
+++ bluez-4.54/audio/control.c 2009-09-26 11:24:04.000000000 -0400
@@ -472,7 +472,7 @@ static gboolean control_cb(GIOChannel *c
struct avrcp_header *avrcp;
int ret, packet_size, operand_count, sock;

- if (!(cond | G_IO_IN))
+ if (!(cond & G_IO_IN))
goto failed;

sock = g_io_channel_unix_get_fd(control->io);
diff -urp bluez-4.54.orig/audio/gsta2dpsink.c bluez-4.54/audio/gsta2dpsink.c
--- bluez-4.54.orig/audio/gsta2dpsink.c 2009-09-26 08:43:56.000000000 -0400
+++ bluez-4.54/audio/gsta2dpsink.c 2009-09-26 11:47:40.000000000 -0400
@@ -143,8 +143,7 @@ remove_element_and_fail:
return NULL;

cleanup_and_fail:
- if (element != NULL)
- g_object_unref(G_OBJECT(element));
+ g_object_unref(G_OBJECT(element));

return NULL;
}
diff -urp bluez-4.54.orig/audio/unix.c bluez-4.54/audio/unix.c
--- bluez-4.54.orig/audio/unix.c 2009-09-26 08:43:56.000000000 -0400
+++ bluez-4.54/audio/unix.c 2009-09-26 12:03:47.000000000 -0400
@@ -658,8 +658,7 @@ static void a2dp_discovery_complete(stru
struct unix_client *c = cl->data;
struct a2dp_data *ca2dp = &c->d.a2dp;

- if (ca2dp && ca2dp->session == session &&
- c->seid == seid) {
+ if (ca2dp->session == session && c->seid == seid) {
lock = c->lock;
break;
}
diff -urp bluez-4.54.orig/compat/hidd.c bluez-4.54/compat/hidd.c
--- bluez-4.54.orig/compat/hidd.c 2009-09-26 08:43:56.000000000 -0400
+++ bluez-4.54/compat/hidd.c 2009-09-26 12:10:14.000000000 -0400
@@ -453,6 +453,7 @@ static void do_connect(int ctl, bdaddr_t
int csk, isk, err;

memset(&req, 0, sizeof(req));
+ name[0] = 0;

err = get_sdp_device_info(src, dst, &req);
if (err < 0 && fakehid)
diff -urp bluez-4.54.orig/lib/sdp.c bluez-4.54/lib/sdp.c
--- bluez-4.54.orig/lib/sdp.c 2009-09-26 08:43:56.000000000 -0400
+++ bluez-4.54/lib/sdp.c 2009-09-26 12:22:08.000000000 -0400
@@ -2026,7 +2026,7 @@ int sdp_get_lang_attr(const sdp_record_t
sdp_data_t *pCode = curr_data;
sdp_data_t *pEncoding = pCode->next;
sdp_data_t *pOffset = pEncoding->next;
- if (pCode && pEncoding && pOffset) {
+ if (pEncoding && pOffset) {
lang = malloc(sizeof(sdp_lang_attr_t));
lang->code_ISO639 = pCode->val.uint16;
lang->encoding = pEncoding->val.uint16;
@@ -3473,6 +3473,7 @@ sdp_record_t *sdp_service_attr_req(sdp_s
rspbuf = malloc(SDP_RSP_BUFFER_SIZE);
if (!reqbuf || !rspbuf) {
errno = ENOMEM;
+ rsp_concat_buf.data = NULL;
goto end;
}
memset((char *) &rsp_concat_buf, 0, sizeof(sdp_buf_t));
@@ -4293,6 +4294,7 @@ int sdp_service_search_attr_req(sdp_sess
if (!reqbuf || !rspbuf) {
errno = ENOMEM;
status = -1;
+ rsp_concat_buf.data = NULL;
goto end;
}

diff -urp bluez-4.54.orig/tools/hcitool.c bluez-4.54/tools/hcitool.c
--- bluez-4.54.orig/tools/hcitool.c 2009-09-26 08:43:56.000000000 -0400
+++ bluez-4.54/tools/hcitool.c 2009-09-26 12:31:28.000000000 -0400
@@ -505,7 +505,7 @@ static void cmd_scan(int dev_id, int arg
uint8_t lap[3] = { 0x33, 0x8b, 0x9e };
int num_rsp, length, flags;
uint8_t cls[3], features[8];
- uint16_t handle;
+ uint16_t handle = 0;
char addr[18], name[249], oui[9], *comp, *tmp;
struct hci_version version;
struct hci_dev_info di;


2009-09-27 08:41:51

by Johan Hedberg

[permalink] [raw]
Subject: Re: [PATCH] init and extra checking fixups

Hi Steve,

On Sat, Sep 26, 2009, Steve Grubb wrote:
> In audio/avdtp.c, the avdtp_setconf_cmd function has an exit jump for failed.
> There are several calls to the goto that do not set err to something, meaning
> that the stack contents are what's used. I set err =0 in the beginning so that
> we no longer use the stack contents, but it seems like there should be some
> general error code that says we failed for an unspecified reason.

> diff -urp bluez-4.54.orig/audio/avdtp.c bluez-4.54/audio/avdtp.c
> --- bluez-4.54.orig/audio/avdtp.c 2009-09-26 08:43:56.000000000 -0400
> +++ bluez-4.54/audio/avdtp.c 2009-09-26 11:17:07.000000000 -0400
> @@ -1248,7 +1248,7 @@ static gboolean avdtp_setconf_cmd(struct
> struct conf_rej rej;
> struct avdtp_local_sep *sep;
> struct avdtp_stream *stream;
> - uint8_t err, category = 0x00;
> + uint8_t err = 0, category = 0x00;
> struct audio_device *dev;
> bdaddr_t src, dst;
> GSList *l;

The right error for the two places is AVDTP_BAD_STATE. Setting that error
before jumping to failed also means that we avoid the initialization upon
declaration for the err variable.

David and Luiz commented already on a few other issues which would be good
to fix too. Furthermore, don't be afraid to split your patches into
smaller logical chunks. That way some of them could have been already
applied and pushed upstream. And please leave out the Signed-off-by line
since we don't use it in bluez.

Johan

2009-09-27 03:01:08

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: Re: [PATCH] init and extra checking fixups

Hi Steve,

On Sat, Sep 26, 2009 at 1:37 PM, Steve Grubb <[email protected].com> wrote:
> diff -urp bluez-4.54.orig/audio/control.c bluez-4.54/audio/control.c
> --- bluez-4.54.orig/audio/control.c ? ? 2009-09-26 08:43:56.000000000 -0400
> +++ bluez-4.54/audio/control.c ?2009-09-26 11:24:04.000000000 -0400
> @@ -472,7 +472,7 @@ static gboolean control_cb(GIOChannel *c
> ? ? ? ?struct avrcp_header *avrcp;
> ? ? ? ?int ret, packet_size, operand_count, sock;
>
> - ? ? ? if (!(cond | G_IO_IN))
> + ? ? ? if (!(cond & G_IO_IN))
> ? ? ? ? ? ? ? ?goto failed;

I don't think this is actually right, if we change it to AND operation
it would mean we won't process any other error condition if it happens
together with G_IO_IN, but still the OR seems wrong here, normally we
use the following check which I believe is more appropriate:


if (cond & (G_IO_HUP | G_IO_ERR))
goto failed;

--
Luiz Augusto von Dentz
Engenheiro de Computa??o

2009-09-27 00:00:39

by David Sainty

[permalink] [raw]
Subject: Re: [PATCH] init and extra checking fixups

Steve Grubb wrote:
> In tools/hcitool.c, around line 687, handle could conceivably be used without
> being initialized. I set it to 0.
>
>

Modern gcc is great at telling you when uninitialised variables might be
used. But it can't do that job if you just initialise the variable at
the start. The error code patch probably falls into the same category.

At the very least for this specific case, handle should be reset at the
start of the loop it's used in, not just at the start of the function.

But it probably makes sense to tidy the code up a bit instead. cc is a
boolean that is true iff handle is valid, so maybe some of those (handle
> 0) tests should go away and be replaced by (cc).

Though this code would be a bit simpler if it didn't try to survive and
continue after malloc() failures, which seems a bit excessive. An error
and exit seems more reasonable from hcitool.

> diff -urp bluez-4.54.orig/tools/hcitool.c bluez-4.54/tools/hcitool.c
> --- bluez-4.54.orig/tools/hcitool.c 2009-09-26 08:43:56.000000000 -0400
> +++ bluez-4.54/tools/hcitool.c 2009-09-26 12:31:28.000000000 -0400
> @@ -505,7 +505,7 @@ static void cmd_scan(int dev_id, int arg
> uint8_t lap[3] = { 0x33, 0x8b, 0x9e };
> int num_rsp, length, flags;
> uint8_t cls[3], features[8];
> - uint16_t handle;
> + uint16_t handle = 0;
> char addr[18], name[249], oui[9], *comp, *tmp;
> struct hci_version version;
> struct hci_dev_info di;
>


2009-10-02 15:26:19

by Steve Grubb

[permalink] [raw]
Subject: Re: [PATCH] init and extra checking fixups

On Friday 02 October 2009 05:30:05 am Johan Hedberg wrote:
> I went ahead and split up this patch myself and also did the few necessary
> fixups to it. The changes are now upstream.

Thanks for fixing up all 3 patches. I apologize for not being able to get to it
this week.

-Steve

2009-10-02 09:30:05

by Johan Hedberg

[permalink] [raw]
Subject: Re: [PATCH] init and extra checking fixups

Hi,

On Sat, Sep 26, 2009, Steve Grubb wrote:
> I was doing some code reviews of the 4.54 release and found a couple
> things that should be fixed up. This patch is looking at things that may not
> have been initialized or is doing value checks that are unnecessary.
>
> In audio/avdtp.c, the avdtp_setconf_cmd function has an exit jump for failed.
> There are several calls to the goto that do not set err to something, meaning
> that the stack contents are what's used. I set err =0 in the beginning so that
> we no longer use the stack contents, but it seems like there should be some
> general error code that says we failed for an unspecified reason.
>
> In audio/control.c, the function control_cb takes a variable cond and first
> thing it or's G_IO_IN with it and uses the result for a test in an if
> statement. I suspect it should be a '&' operator.
>
> In audio/unix.c, the function a2dp_discovery_complete at line 659 has a
> variable ca2dp. There is a check at line 661 to see that its not NULL. It can
> never be NULL because its position in the unix_client structure will never
> let it be NULL. So, this check should be dropped.
>
> In compat/hidd.c, there is a function do_connect with a variable, name. It
> could conceivably be uninitialized when used in a strcmp at line 473.
>
> In lib/sdp.c, the function sdp_get_lang_attr has a variable pCode that is
> being checked for non-NULL at line 2029. It gets its value from curr_data which
> has to be non-NULL to enter the loop. So, checking pCode does nothing. It
> should be dropped.
>
> Same file, in the function sdp_service_attr_req there is a variable
> rsp_concat_buf. If the allocations for reqbuf or rspbuf fail, it goes to end
> where it will attempt to free rsp_concat_buf.data which is whatever the stack
> contents are. This same issue pops up again in the function,
> sdp_service_search_attr_req a little farther down.
>
> NOT FIXED - In src/sdpd-service.c, the function create_ext_inquiry_response
> has a variable uuid that is used at line 223 in an equality test without
> having been initialized. No idea what the right code for that is.
>
> In tools/hcitool.c, around line 687, handle could conceivably be used without
> being initialized. I set it to 0.
>
> Signed-off-by: Steve Grubb <[email protected]>

I went ahead and split up this patch myself and also did the few necessary
fixups to it. The changes are now upstream.

Johan