Bug 31138 – Uninitialized memory read in WebCore::Page::userStyleSheetLocationChanged()

• Status: RESOLVED
• Resolution: FIXED
• Component: WebCore Misc.

[Dan Kegel]

Found via chromium linux layout valgrind bot on
LayoutTests/platform/mac/fast/loader/user-stylesheet-fast-path.html .
Valgrind complains

Invalid read of size 1
   at strlen (mc_replace_strmem.c:275)
   by WebCore::String::fromUTF8(char const*) (String.cpp:682)
   by WebCore::Page::userStyleSheetLocationChanged() (Page.cpp:545)
 Address 0xd60f4af is 0 bytes after a block of size 31 alloc'd
   at malloc (vg_replace_malloc.c:195)
   ...
   by WebCore::base64Decode(WTF::Vector<char, 0ul> const&, WTF::Vector<char, 0ul>&) (Base64.cpp:134)
   by WebCore::Page::userStyleSheetLocationChanged() (Page.cpp:544)

Looks like someone forgot to specify a length.  I'll attach a fix.

[Dan Kegel]

Created attachment 42510 [details]
Supply missing length argument to avoid buffer overrun

le voilà!

[Alexey Proskuryakov]

Comment on attachment 42510 [details]
Supply missing length argument to avoid buffer overrun

+        * page/Page.cpp:
+        (WebCore::Page::userStyleSheetLocationChanged):

Ideally, there should be per-function comments explaining changes.

r=me as is.

[Eric Seidel (no email)]

Comment on attachment 42510 [details]
Supply missing length argument to avoid buffer overrun

I wonder if there are other places we call from UTF8 and need fixes? Since dan's not a committer, adding this to the cq.

[WebKit Commit Bot]

Comment on attachment 42510 [details]
Supply missing length argument to avoid buffer overrun

Clearing flags on attachment: 42510

Committed r50545: <http://trac.webkit.org/changeset/50545>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.