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On Thursday 12 April 2012 13:30:38 Mike Frysinger wrote: > The current tftp structure does not work when fortification is enabled. > Starting with gcc-4.5, more size checking was added to trigger these. > Older versions just didn't have enough information, so they returned -1 > as the sizes. > > First, the tu_stuff field is declared as 1 byte (when it's really an > arbitrary length C string), so attempting to strcpy() with it results > in crashes. This fails with _FORTIFY_SOURCE=1. > > Second, even if we change that to [0] (since gcc does not allow flexible > array members in an union), gcc is not smart enough to see that they are > two overlapping flexible arrays (tu_stuff and tu_data), so it will still > trigger an abort with _FORTIFY_SOURCE=2. This is because it thinks that > tu_stuff is 0 bytes and tu_data comes after it. > > Talking to upstream gcc, they don't seem terribly inclined to fix the > 2nd issue, but even if they did, we still have plenty of 4.5 and 4.6 > installs that would hit problems. > > So, let's re-order with a few more anonymous structs & unions so that > the fields are laid out with a zero-length array always as the last > field. This seems to fix things with gcc-4.6, and the tftp-hpa pkg > continues to build & work. any complaints on this version ? -mike
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