From fb27a570adc18419ea185eeeb82333ba2c643cdb Mon Sep 17 00:00:00 2001 From: Leandro Lupori Date: Mon, 24 Aug 2020 13:40:35 +0000 Subject: [PATCH] [PowerPC] Make new auxv format default Assume ELF images without OSREL use the new auxv format. This is specially important for rtld, that is not tagged. Using direct exec mode with new (ELFv2) binaries that expect the new auxv format would result in crashes otherwise. Unfortunately, this may break direct exec'ing old binaries, but it seems better to correctly support new binaries by default, considering the transition to ELFv2 happened quite some time ago. If needed, a sysctl may be added to allow old auxv format to be used when OSREL is not found. Reviewed by: bdragon Sponsored by: Eldorado Research Institute (eldorado.org.br) Differential Revision: https://reviews.freebsd.org/D25651 --- sys/powerpc/powerpc/elf_common.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/sys/powerpc/powerpc/elf_common.c b/sys/powerpc/powerpc/elf_common.c index f9d2dec624e..c7460848b89 100644 --- a/sys/powerpc/powerpc/elf_common.c +++ b/sys/powerpc/powerpc/elf_common.c @@ -36,7 +36,22 @@ __elfN(powerpc_copyout_auxargs)(struct image_params *imgp, uintptr_t base) Elf_Auxinfo *argarray, *pos; int error; - if (imgp->proc->p_osrel >= P_OSREL_POWERPC_NEW_AUX_ARGS) + /* + * XXX If we can't find image's OSREL, assume it uses the new auxv + * format. + * + * This is specially important for rtld, that is not tagged. Using + * direct exec mode with new (ELFv2) binaries that expect the new auxv + * format would result in crashes otherwise. + * + * Unfortunately, this may break direct exec'ing old binaries, + * but it seems better to correctly support new binaries by default, + * considering the transition to ELFv2 happened quite some time + * ago. If needed, a sysctl may be added to allow old auxv format to + * be used when OSREL is not found. + */ + if (imgp->proc->p_osrel >= P_OSREL_POWERPC_NEW_AUX_ARGS || + imgp->proc->p_osrel == 0) return (__elfN(freebsd_copyout_auxargs)(imgp, base)); args = (Elf_Auxargs *)imgp->auxargs;