* [Bug libdw/23301] New: free on unitialized value
@ 2018-06-17 8:45 luizluca at gmail dot com
2018-06-18 11:32 ` [Bug libdw/23301] " mark at klomp dot org
0 siblings, 1 reply; 2+ messages in thread
From: luizluca at gmail dot com @ 2018-06-17 8:45 UTC (permalink / raw)
To: elfutils-devel
https://sourceware.org/bugzilla/show_bug.cgi?id=23301
Bug ID: 23301
Summary: free on unitialized value
Product: elfutils
Version: unspecified
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: libdw
Assignee: unassigned at sourceware dot org
Reporter: luizluca at gmail dot com
CC: elfutils-devel at sourceware dot org
Target Milestone: ---
Created attachment 11075
--> https://sourceware.org/bugzilla/attachment.cgi?id=11075&action=edit
patch: dwarf_getsrclines.c: Fix unitialized usage of filelist
I'm getting this error with 0.172:
dwarf_getsrclines.c: In function 'read_srclines':
dwarf_getsrclines.c:1074:7: error: 'filelist' may be used uninitialized in this
function [-Werror=maybe-uninitialized]
free (filelist);
^~~~~~~~~~~~~~~
It seems that gcc is right here as there is "ifs" that go to "out" (where
filelist is freed) before freelist is initialized. I fixed by just moving
filelist initialization to before the first usage of "goto out;". Maybe there
is a more elegant approach.
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* [Bug libdw/23301] free on unitialized value
2018-06-17 8:45 [Bug libdw/23301] New: free on unitialized value luizluca at gmail dot com
@ 2018-06-18 11:32 ` mark at klomp dot org
0 siblings, 0 replies; 2+ messages in thread
From: mark at klomp dot org @ 2018-06-18 11:32 UTC (permalink / raw)
To: elfutils-devel
https://sourceware.org/bugzilla/show_bug.cgi?id=23301
Mark Wielaard <mark at klomp dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2018-06-17
CC| |mark at klomp dot org
Assignee|unassigned at sourceware dot org |mark at klomp dot org
Ever confirmed|0 |1
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #1 from Mark Wielaard <mark at klomp dot org> ---
Created attachment 11076
--> https://sourceware.org/bugzilla/attachment.cgi?id=11076&action=edit
libdw: Initialize filelist earlier in dwarf_getsrclines.c read_srclines.
Hi,
gcc is wrong, filelist will not be used/freed if nfilelist == 0, and filelist
will be initialized if nfilelist != 0. But this might be hard to see for the
compiler. BTW which gcc version is this, any special CFLAGS used?
Instead of moving the whole block of code around I think just explicitly
setting filelist to NULL when we initialize nfilelist = 0 should do the trick.
Could you test the slightly changed patch attached?
Also would it me OK to add a Signed-off-by: Luiz Angelo Daros de Luca
<luizluca@gmail.com> line as described in
https://sourceware.org/git/?p=elfutils.git;a=blob_plain;f=CONTRIBUTING;hb=HEAD
Thanks,
Mark
--- Comment #2 from Luiz Angelo Daros de Luca <luizluca at gmail dot com> ---
Mark,
It works. Gcc does not blame me anymore.
Thanks.
--- Comment #3 from Mark Wielaard <mark at klomp dot org> ---
commit 9e16a100bf8e0d43415253fe8cfd3ba1d8e637d1
Author: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Date: Sun Jun 17 11:34:08 2018 +0200
libdw: Initialize filelist earlier in dwarf_getsrclines.c read_srclines.
I'm getting this error with 0.172:
dwarf_getsrclines.c: In function 'read_srclines':
dwarf_getsrclines.c:1074:7: error: 'filelist' may be used uninitialized in
t
free (filelist);
^~~~~~~~~~~~~~~
It seems that gcc is right here as there is "ifs" that go to "out"
(where filelist is freed) before freelist is initialized.
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
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