search for: executablestacks

...> > > Where does fstype come from there? I am going to guess it is either > > busybox or linked against klibc? > > > > klibc has known problems with executable stacks due to its trampoline > > implementation: > > https://wiki.ubuntu.com/SecurityTeam/Roadmap/ExecutableStacks > > Yeah. It comes from klibc-utils. This is exactly what I was worried about back in Feb: https://lore.kernel.org/lkml/202002251341.48BC06E at keescook/ This warning, combined with klibc-based initrds, makes the whole thing pointless because it will always warn once on boot for the klibc...

With latest kernel (Linus tree as of 5.6 merge window), I get the following warning in the kernel 'dmesg': [ 5.746588] process '/bin/sh' started with executable stack This comes from commit https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/fs/exec.c?id=47a2ebb7f5053387f5753b524f4920b9b829f922 "execve: warn if process starts with executable

...unexpected. And it is the case for all > > klibc tools. > > > > How can we fix that ? > > klibc uses trampolines for its setjmp implementation. I ran into this > years ago when eradicating executable stacks from Ubuntu: > https://wiki.ubuntu.com/SecurityTeam/Roadmap/ExecutableStacks I've looked at all the setjmp() implementations and didn't spot any use of trampolines. Ben. -- Ben Hutchings If more than one person is responsible for a bug, no one is at fault. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: a...

...Indeed, the stack is rwx, which is unexpected. And it is the case for all > klibc tools. > > How can we fix that ? klibc uses trampolines for its setjmp implementation. I ran into this years ago when eradicating executable stacks from Ubuntu: https://wiki.ubuntu.com/SecurityTeam/Roadmap/ExecutableStacks -- Kees Cook

...es fstype come from there? I am going to guess it is either > > > busybox or linked against klibc? > > > > > > klibc has known problems with executable stacks due to its trampoline > > > implementation: > > > https://wiki.ubuntu.com/SecurityTeam/Roadmap/ExecutableStacks > > > > Yeah. It comes from klibc-utils. > > This is exactly what I was worried about back in Feb: > https://lore.kernel.org/lkml/202002251341.48BC06E at keescook/ > > This warning, combined with klibc-based initrds, makes the whole thing > pointless because it wil...