| 1 |
On Saturday 17 February 2007, Brian Harring wrote: |
| 2 |
> On Sat, Feb 17, 2007 at 09:39:58AM -0500, Mike Frysinger wrote: |
| 3 |
> > On Saturday 17 February 2007, Brian Harring wrote: |
| 4 |
> > > Security impact is from a pkg potentially dragging along old libs; if |
| 5 |
> > > you've got a stable pkg that gets an update once every blue moon, it |
| 6 |
> > > can hold onto the lib for a *long* time while still using the lib; |
| 7 |
> > > thus if a vuln. in the lib, said pkg still is screwed. |
| 8 |
> > |
| 9 |
> > umm, no ... the package itself is updated against the new copy while the |
| 10 |
> > old copy exists for other packages that have already been built |
| 11 |
> |
| 12 |
> Suspect you're ignoring soname changes, which is about all this patch |
| 13 |
> would address- for example, ssl's old form of breakage. In that case, |
| 14 |
> *yes* the package gets updated, anything recompiled should get the |
| 15 |
> correct lib |
| 16 |
|
| 17 |
i'm not ignoring soname changes, those are exactly what i'm talking about |
| 18 |
|
| 19 |
> (assuming the code knows the appropriate linker args) |
| 20 |
|
| 21 |
there is no such thing ... it's always "-lfoo" |
| 22 |
|
| 23 |
> the old vuln. lib still will hang around as long as anything refs it. |
| 24 |
|
| 25 |
of course and this is the desired behavior ... people need to run |
| 26 |
revdep-rebuild, there's no two ways about it |
| 27 |
|
| 28 |
> > > Other angle is someone intentionally forcing usage of a known bad |
| 29 |
> > > library that is still dangling. Corner case, but doable. |
| 30 |
> > |
| 31 |
> > as i said, this is the "invalid" syntax: |
| 32 |
> > ... /usr/lib/libfoo.so.3 ... |
| 33 |
> |
| 34 |
> Not to LD_PRELOAD :) |
| 35 |
> |
| 36 |
> Haven't tried anything crazy, but suspect it can be abused to override |
| 37 |
> to the old. |
| 38 |
|
| 39 |
again, not in any scenario that actually matters ... so this too is a |
| 40 |
pointless line of thought to pursue as it has no real security impact |
| 41 |
|
| 42 |
> > > Bit curious how this is going to behave if via linked in libs, new loc |
| 43 |
> > > and old get loaded alongside... |
| 44 |
> > |
| 45 |
> > this would require multiple libraries to be involved in the equation and |
| 46 |
> > the answer is undefined behavior which most certainly result in runtime |
| 47 |
> > failures ... |
| 48 |
> |
| 49 |
> Point there was that instead of just bailing with "lib is missing", |
| 50 |
> suspect it'll manage to run, then segfault at potentially crappy |
| 51 |
> times. |
| 52 |
|
| 53 |
this is really an outside case and not worth worrying over |
| 54 |
-mike |
Archives