From c07f0f872d21c891ec351eccf996f445a63a30e7 Mon Sep 17 00:00:00 2001 From: delphij Date: Wed, 27 Jan 2016 07:20:55 +0000 Subject: Implement AT_SECURE properly. AT_SECURE auxv entry has been added to the Linux 2.5 kernel to pass a boolean flag indicating whether secure mode should be enabled. 1 means that the program has changes its credentials during the execution. Being exported AT_SECURE used by glibc issetugid() call. Submitted by: imp, dchagin Security: FreeBSD-SA-16:10.linux Security: CVE-2016-1883 --- sys/amd64/linux/linux_sysvec.c | 4 +++- sys/amd64/linux32/linux32_sysvec.c | 4 +++- sys/i386/linux/linux_sysvec.c | 4 +++- 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c index d49ca79..0bdcba0 100644 --- a/sys/amd64/linux/linux_sysvec.c +++ b/sys/amd64/linux/linux_sysvec.c @@ -271,6 +271,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) Elf_Addr *pos; struct ps_strings *arginfo; struct proc *p; + int issetugid; p = imgp->proc; arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; @@ -281,6 +282,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) args = (Elf64_Auxargs *)imgp->auxargs; pos = base + (imgp->args->argc + imgp->args->envc + 2); + issetugid = p->p_flag & P_SUGID ? 1 : 0; AUXARGS_ENTRY(pos, LINUX_AT_SYSINFO_EHDR, imgp->proc->p_sysent->sv_shared_page_base); AUXARGS_ENTRY(pos, LINUX_AT_HWCAP, cpu_feature); @@ -296,7 +298,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid); AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid); AUXARGS_ENTRY(pos, AT_EGID, imgp->proc->p_ucred->cr_svgid); - AUXARGS_ENTRY(pos, LINUX_AT_SECURE, 0); + AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid); AUXARGS_ENTRY(pos, LINUX_AT_PLATFORM, PTROUT(linux_platform)); AUXARGS_ENTRY(pos, LINUX_AT_RANDOM, imgp->canary); if (imgp->execpathp != 0) diff --git a/sys/amd64/linux32/linux32_sysvec.c b/sys/amd64/linux32/linux32_sysvec.c index 7d3615e..f89b8fa 100644 --- a/sys/amd64/linux32/linux32_sysvec.c +++ b/sys/amd64/linux32/linux32_sysvec.c @@ -230,6 +230,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) Elf32_Addr *base; Elf32_Addr *pos; struct linux32_ps_strings *arginfo; + int issetugid; arginfo = (struct linux32_ps_strings *)LINUX32_PS_STRINGS; @@ -239,6 +240,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) args = (Elf32_Auxargs *)imgp->auxargs; pos = base + (imgp->args->argc + imgp->args->envc + 2); + issetugid = imgp->proc->p_flag & P_SUGID ? 1 : 0; AUXARGS_ENTRY_32(pos, LINUX_AT_SYSINFO_EHDR, imgp->proc->p_sysent->sv_shared_page_base); AUXARGS_ENTRY_32(pos, LINUX_AT_SYSINFO, linux32_vsyscall); @@ -261,7 +263,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) AUXARGS_ENTRY_32(pos, AT_FLAGS, args->flags); AUXARGS_ENTRY_32(pos, AT_ENTRY, args->entry); AUXARGS_ENTRY_32(pos, AT_BASE, args->base); - AUXARGS_ENTRY_32(pos, LINUX_AT_SECURE, 0); + AUXARGS_ENTRY_32(pos, LINUX_AT_SECURE, issetugid); AUXARGS_ENTRY_32(pos, AT_UID, imgp->proc->p_ucred->cr_ruid); AUXARGS_ENTRY_32(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid); AUXARGS_ENTRY_32(pos, AT_GID, imgp->proc->p_ucred->cr_rgid); diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c index cc5fcaa..c4a5ee5 100644 --- a/sys/i386/linux/linux_sysvec.c +++ b/sys/i386/linux/linux_sysvec.c @@ -238,11 +238,13 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) Elf32_Addr *uplatform; struct ps_strings *arginfo; register_t *pos; + int issetugid; KASSERT(curthread->td_proc == imgp->proc, ("unsafe elf_linux_fixup(), should be curproc")); p = imgp->proc; + issetugid = imgp->proc->p_flag & P_SUGID ? 1 : 0; arginfo = (struct ps_strings *)p->p_sysent->sv_psstrings; uplatform = (Elf32_Addr *)((caddr_t)arginfo - linux_szplatform); args = (Elf32_Auxargs *)imgp->auxargs; @@ -270,7 +272,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp) AUXARGS_ENTRY(pos, AT_FLAGS, args->flags); AUXARGS_ENTRY(pos, AT_ENTRY, args->entry); AUXARGS_ENTRY(pos, AT_BASE, args->base); - AUXARGS_ENTRY(pos, LINUX_AT_SECURE, 0); + AUXARGS_ENTRY(pos, LINUX_AT_SECURE, issetugid); AUXARGS_ENTRY(pos, AT_UID, imgp->proc->p_ucred->cr_ruid); AUXARGS_ENTRY(pos, AT_EUID, imgp->proc->p_ucred->cr_svuid); AUXARGS_ENTRY(pos, AT_GID, imgp->proc->p_ucred->cr_rgid); -- cgit v1.1