Do not free pointer when you are going to use it

small patch that fixes potential crash in xdg_mime_get_mime_type_for_file() - use of pointer after being freed.

BUG=

Committed: https://crrev.com/c432cac0a0beb77c63081536fc9d53b40e642cbf
Cr-Commit-Position: refs/heads/master@{#326352}

[gburanov, 2015-03-27 08:30:54]

gburanov@gmail.com changed reviewers:
+ willchan@chromium.org

[gburanov, 2015-03-27 08:32:12]

gburanov@gmail.com changed reviewers:
+ danakj@chromium.org
- willchan@chromium.org

[danakj, 2015-04-08 16:59:49]

danakj@chromium.org changed reviewers:
+ thestig@chromium.org

[danakj, 2015-04-08 16:59:50]

-danakj +thestig

[gburanov, 2015-04-08 17:18:55]

On 2015/04/08 16:59:50, danakj wrote:
> -danakj +thestig

I have created a bug for original rep already
https://bugs.freedesktop.org/show_bug.cgi?id=89955

[Lei Zhang, 2015-04-08 19:21:01]

You are welcome to fix the bug, but it has no real effect because Chromium does
not call xdg_mime_get_mime_type_for_file().

If you choose to update upstream first, then you should probably just update
Chromium's copy to the latest xdg_mime.

If you choose to patch Chromium's copy first, then you need to add a .patch file
and update README.chromium.

BTW, others have fixed this in their copy of xdgmime.c. I'm not sure why the
change never got upstreamed.
http://repo.or.cz/w/rox-filer.git/commitdiff/97f32448e491de3a824ce7e3723d3db9...

[Lei Zhang, 2015-04-08 19:21:16]

Also, there's a typo in the CL description.

[gburanov, 2015-04-09 08:49:50]

The CQ bit was checked by gburanov@gmail.com

[gburanov, 2015-04-09 08:49:54]

The CQ bit was unchecked by gburanov@gmail.com

[gburanov, 2015-04-15 16:17:54]

On 2015/04/08 19:21:16, Lei Zhang (slow to respond) wrote:
> Also, there's a typo in the CL description.

Hi, Lei. I have
1. Added patch
2. Modified README
3. Fixed typo

[Lei Zhang, 2015-04-16 18:31:35]

https://codereview.chromium.org/1037023002/diff/60001/base/third_party/xdg_mi...
File base/third_party/xdg_mime/README.chromium (right):

https://codereview.chromium.org/1037023002/diff/60001/base/third_party/xdg_mi...
base/third_party/xdg_mime/README.chromium:11: - free_pointer_later.patch: small
patch that fixes potential crash - use pointer after being freed
one more space in front

https://codereview.chromium.org/1037023002/diff/60001/base/third_party/xdg_mi...
File base/third_party/xdg_mime/xdgmime.c (right):

https://codereview.chromium.org/1037023002/diff/60001/base/third_party/xdg_mi...
base/third_party/xdg_mime/xdgmime.c:563: if (mime_type) {
So how about:

if (!mime_type)
  mime_type = _xdg_binary_or_text_fallback(data, bytes_read);

free (data);
return mime_type;

[gburanov, 2015-04-20 09:50:07]

Added all fixes according to suggestions

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
File base/third_party/xdg_mime/README.chromium (right):

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
base/third_party/xdg_mime/README.chromium:10: - compile.patch: small tweaks to
make the code compile.
Added spaces exactly as in base/third_party/dmg_fp/README.chromium

[danakj, 2015-04-20 17:09:07]

danakj@chromium.org changed reviewers:
- danakj@chromium.org

[Lei Zhang, 2015-04-20 19:14:02]

- The file "free_poiner_later.patch" has a typo in the name.
- Please write a more descriptive CL description. e.g. "Fix foo in bar()"
instead of just "Fix foo".

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
File base/third_party/xdg_mime/README.chromium (right):

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
base/third_party/xdg_mime/README.chromium:11: - free_pointer_later.patch: small
patch that fixes potential crash - use pointer after being freed.
Would you mind not going over 80 chars / line?

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
File base/third_party/xdg_mime/xdgmime.c (right):

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
base/third_party/xdg_mime/xdgmime.c:563: if (!mime_type) {
No need for braces. The rest of the code only use braces when necessary. You
should too.

[gburanov, 2015-04-22 14:21:56]

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
File base/third_party/xdg_mime/README.chromium (right):

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
base/third_party/xdg_mime/README.chromium:11: - free_pointer_later.patch: small
patch that fixes potential crash - use pointer after being freed.
On 2015/04/20 19:14:02, Lei Zhang wrote:
> Would you mind not going over 80 chars / line?

done!

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
File base/third_party/xdg_mime/xdgmime.c (right):

https://codereview.chromium.org/1037023002/diff/80001/base/third_party/xdg_mi...
base/third_party/xdg_mime/xdgmime.c:563: if (!mime_type) {
On 2015/04/20 19:14:02, Lei Zhang wrote:
> No need for braces. The rest of the code only use braces when necessary. You
> should too.

Done.

[Lei Zhang, 2015-04-22 17:30:12]

lgtm

[gburanov, 2015-04-22 17:39:59]

The CQ bit was checked by gburanov@gmail.com

[commit-bot: I haz the power, 2015-04-22 17:42:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1037023002/100001

[commit-bot: I haz the power, 2015-04-22 19:07:01]

Committed patchset #6 (id:100001)

[commit-bot: I haz the power, 2015-04-22 19:08:03]

Patchset 6 (id:??) landed as
https://crrev.com/c432cac0a0beb77c63081536fc9d53b40e642cbf
Cr-Commit-Position: refs/heads/master@{#326352}