On Tue, Dec 16, 2025 at 4:26 PM H. Peter Anvin <[email protected]> wrote: > > Currently the vdso doesn't include .note.gnu.property or a GNU noexec > stack annotation (the -z noexecstack in the linker script is > ineffective because we specify PHDRs explicitly.) > > The motivation is that the dynamic linker currently do not check > these. > > However, this is a weak excuse: the vdso*.so are also supposed to be > usable at link libraries, and there is no reason why the dynamic > linker might not want or need to check these in the future, so add > them back in -- it is trivial enough. > > Use symbolic constants for the PHDR permission flags. > > [ v4: drop unrelated formatting changes ] > > Signed-off-by: H. Peter Anvin (Intel) <[email protected]> > --- > arch/x86/entry/vdso/common/vdso-layout.lds.S | 38 ++++++++++++-------- > 1 file changed, 23 insertions(+), 15 deletions(-) > > diff --git a/arch/x86/entry/vdso/common/vdso-layout.lds.S > b/arch/x86/entry/vdso/common/vdso-layout.lds.S > index ec1ac191a057..a1e30be3e83d 100644 > --- a/arch/x86/entry/vdso/common/vdso-layout.lds.S > +++ b/arch/x86/entry/vdso/common/vdso-layout.lds.S > @@ -47,18 +47,18 @@ SECTIONS > *(.gnu.linkonce.b.*) > } :text > > - /* > - * Discard .note.gnu.property sections which are unused and have > - * different alignment requirement from vDSO note sections. > - */ > - /DISCARD/ : { > + .note.gnu.property : { > *(.note.gnu.property) > - } > - .note : { *(.note.*) } :text :note > - > - .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr > - .eh_frame : { KEEP (*(.eh_frame)) } :text > + } :text :note :gnu_property > + .note : { > + *(.note*) > + } :text :note > > + .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr > + .eh_frame : { > + KEEP (*(.eh_frame)) > + *(.eh_frame.*) > + } :text > > /* > * Text is well-separated from actual data: there's plenty of > @@ -87,15 +87,23 @@ SECTIONS > * Very old versions of ld do not recognize this name token; use the > constant. > */ > #define PT_GNU_EH_FRAME 0x6474e550 > +#define PT_GNU_STACK 0x6474e551 > +#define PT_GNU_PROPERTY 0x6474e553
Do we even still support the old linkers that need these constants? Brian Gerst
