On Thu, Nov 24, 2016 at 02:50:23PM -0200, Henrique de Moraes Holschuh wrote: > On Thu, 24 Nov 2016, Adrian Bunk wrote: > > On Wed, Nov 23, 2016 at 11:50:12PM -0200, Henrique de Moraes Holschuh wrote: > > > On Thu, 24 Nov 2016, Kurt Roeckx wrote: > > >... > > > > > So, if Qt *ever* exposes its use of openssl anywere in its APIs, it > > > > > might not be safe. If it doesn't (i.e. at most you have a qt flag > > > > > that > > > > > says "use SSL", etc), then it should be fine. > > > > > > > > It seems to be doing this in qtbase5-private-dev. Not sure if > > > > there are actually any users of it. > > > > > > If it does, all reverse *build* dependencies would need to be inspected, > > > then. > > > > > > AFAIK, that means they must not link to anything that could link to a > > > different libssl than the one used by qt5. If they do, everything needs > > > to be inspected down to the details to ensure nothing will ever leak > > > openssl contextes and data structures across a library boundary > > > (including the application). > > > > If inspection is not easily possible, then adding a dependency on > > libssl1.0-dev to qtbase5-private-dev should be sufficient to > > ensure that this is not leaked to a different OpenSSL version. > > How so? > > Consider the flattened tree (app is the root, - denotes a branch). > > A - B - App - C - D > > Where A and D are two versions of openssl. B and C are libs (suppose B > comes from qtbase5-private-dev) from different source packages.
Where does App get the definitions/declarations for the contextes and data structures it could leak between A and D? If they are part of the B API and part of the C API, then they are used in the header files shipped in b-dev and c-dev. If both b-dev and c-dev would depend on the libssl*-dev they use, then App cannot be compiled with both B and C unless these use the same OpenSSL. Any mismatch would very quickly be reported as a FTBFS bug. cu Adrian -- "Is there not promise of rain?" Ling Tan asked suddenly out of the darkness. There had been need of rain for many days. "Only a promise," Lao Er said. Pearl S. Buck - Dragon Seed