From bc3d7bf61a9eaecccc84dc2ecc2a9a3fa4f5ec47 Mon Sep 17 00:00:00 2001 From: Gabriel Krisman Bertazi <krisman@collabora.com> Date: Sat, 3 Oct 2020 23:25:31 -0400 Subject: elf: Expose ELF header in compat_start_thread() Like it is done for SET_PERSONALITY with x86, which requires the ELF header to select correct personality parameters, x86 requires the headers on compat_start_thread() to choose starting CS for ELF32 binaries, instead of relying on the going-away TIF_IA32/X32 flags. Add an indirection macro to ELF invocations of START_THREAD, that x86 can reimplement to receive the extra parameter just for ELF files. This requires no changes to other architectures who don't need the header information, they can continue to use the original start_thread for ELF and non-ELF binaries, and it prevents affecting non-ELF code paths for x86. Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201004032536.1229030-6-krisman@collabora.com --- fs/binfmt_elf.c | 2 +- fs/compat_binfmt_elf.c | 9 +++++++-- include/linux/elf.h | 5 +++++ 3 files changed, 13 insertions(+), 3 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index b6b3d052ca86..b23f7553fe9b 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1307,7 +1307,7 @@ out_free_interp: #endif finalize_exec(bprm); - start_thread(regs, elf_entry, bprm->p); + START_THREAD(elf_ex, regs, elf_entry, bprm->p); retval = 0; out: return retval; diff --git a/fs/compat_binfmt_elf.c b/fs/compat_binfmt_elf.c index 2d24c765cbd7..12b991368f0a 100644 --- a/fs/compat_binfmt_elf.c +++ b/fs/compat_binfmt_elf.c @@ -106,8 +106,13 @@ #endif #ifdef compat_start_thread -#undef start_thread -#define start_thread compat_start_thread +#define COMPAT_START_THREAD(ex, regs, new_ip, new_sp) \ + compat_start_thread(regs, new_ip, new_sp) +#endif + +#ifdef COMPAT_START_THREAD +#undef START_THREAD +#define START_THREAD COMPAT_START_THREAD #endif #ifdef compat_arch_setup_additional_pages diff --git a/include/linux/elf.h b/include/linux/elf.h index 5d5b0321da0b..6dbcfe7a3fd7 100644 --- a/include/linux/elf.h +++ b/include/linux/elf.h @@ -22,6 +22,11 @@ SET_PERSONALITY(ex) #endif +#ifndef START_THREAD +#define START_THREAD(elf_ex, regs, elf_entry, start_stack) \ + start_thread(regs, elf_entry, start_stack) +#endif + #define ELF32_GNU_PROPERTY_ALIGN 4 #define ELF64_GNU_PROPERTY_ALIGN 8 -- cgit v1.2.3