Date: Thu, 30 Dec 2021 15:36:37 GMT From: Marcin Wojtas <mw@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: 16a900ae0242 - stable/13 - setrlimit: Take stack gap into account. Message-ID: <202112301536.1BUFabno011016@gitrepo.freebsd.org>
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The branch stable/13 has been updated by mw: URL: https://cgit.FreeBSD.org/src/commit/?id=16a900ae02427e6ab3c91282847eba553f4dcd89 commit 16a900ae02427e6ab3c91282847eba553f4dcd89 Author: Dawid Gorecki <dgr@semihalf.com> AuthorDate: 2021-10-13 19:01:08 +0000 Commit: Marcin Wojtas <mw@FreeBSD.org> CommitDate: 2021-12-30 15:24:59 +0000 setrlimit: Take stack gap into account. Calling setrlimit with stack gap enabled and with low values of stack resource limit often caused the program to abort immediately after exiting the syscall. This happened due to the fact that the resource limit was calculated assuming that the stack started at sv_usrstack, while with stack gap enabled the stack is moved by a random number of bytes. Save information about stack size in struct vmspace and adjust the rlim_cur value. If the rlim_cur and stack gap is bigger than rlim_max, then the value is truncated to rlim_max. PR: 253208 Reviewed by: kib Obtained from: Semihalf Sponsored by: Stormshield MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D31516 (cherry picked from commit 889b56c8cd84c9a9f2d9e3b019c154d6f14d9021) --- sys/kern/imgact_elf.c | 5 +++-- sys/kern/kern_exec.c | 11 ++++++++--- sys/kern/kern_resource.c | 3 +++ sys/sys/imgact_elf.h | 2 +- sys/sys/sysent.h | 2 +- sys/vm/vm_map.c | 2 ++ sys/vm/vm_map.h | 1 + 7 files changed, 19 insertions(+), 7 deletions(-) diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c index 567c1094bfdc..102863026a9a 100644 --- a/sys/kern/imgact_elf.c +++ b/sys/kern/imgact_elf.c @@ -2892,7 +2892,7 @@ __elfN(untrans_prot)(vm_prot_t prot) return (flags); } -void +vm_size_t __elfN(stackgap)(struct image_params *imgp, uintptr_t *stack_base) { uintptr_t range, rbase, gap; @@ -2900,7 +2900,7 @@ __elfN(stackgap)(struct image_params *imgp, uintptr_t *stack_base) pct = __elfN(aslr_stack_gap); if (pct == 0) - return; + return (0); if (pct > 50) pct = 50; range = imgp->eff_stack_sz * pct / 100; @@ -2908,4 +2908,5 @@ __elfN(stackgap)(struct image_params *imgp, uintptr_t *stack_base) gap = rbase % range; gap &= ~(sizeof(u_long) - 1); *stack_base -= gap; + return (gap); } diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c index 246d72234a29..a6f333eec9e2 100644 --- a/sys/kern/kern_exec.c +++ b/sys/kern/kern_exec.c @@ -1224,6 +1224,7 @@ exec_new_vmspace(struct image_params *imgp, struct sysentvec *sv) stack_prot, error, vm_mmap_to_errno(error)); return (vm_mmap_to_errno(error)); } + vmspace->vm_stkgap = 0; /* * vm_ssize and vm_maxsaddr are somewhat antiquated concepts, but they @@ -1634,12 +1635,16 @@ exec_args_get_begin_envv(struct image_args *args) void exec_stackgap(struct image_params *imgp, uintptr_t *dp) { + struct proc *p = imgp->proc; + if (imgp->sysent->sv_stackgap == NULL || - (imgp->proc->p_fctl0 & (NT_FREEBSD_FCTL_ASLR_DISABLE | + (p->p_fctl0 & (NT_FREEBSD_FCTL_ASLR_DISABLE | NT_FREEBSD_FCTL_ASG_DISABLE)) != 0 || - (imgp->map_flags & MAP_ASLR) == 0) + (imgp->map_flags & MAP_ASLR) == 0) { + p->p_vmspace->vm_stkgap = 0; return; - imgp->sysent->sv_stackgap(imgp, dp); + } + p->p_vmspace->vm_stkgap = imgp->sysent->sv_stackgap(imgp, dp); } /* diff --git a/sys/kern/kern_resource.c b/sys/kern/kern_resource.c index 0ea863917727..ed15f02eedbc 100644 --- a/sys/kern/kern_resource.c +++ b/sys/kern/kern_resource.c @@ -672,6 +672,9 @@ kern_proc_setrlimit(struct thread *td, struct proc *p, u_int which, if (limp->rlim_max < 0) limp->rlim_max = RLIM_INFINITY; + if (which == RLIMIT_STACK && limp->rlim_cur != RLIM_INFINITY) + limp->rlim_cur += p->p_vmspace->vm_stkgap; + oldssiz.rlim_cur = 0; newlim = lim_alloc(); PROC_LOCK(p); diff --git a/sys/sys/imgact_elf.h b/sys/sys/imgact_elf.h index ca95798c7288..b4e8d8d42980 100644 --- a/sys/sys/imgact_elf.h +++ b/sys/sys/imgact_elf.h @@ -106,7 +106,7 @@ int __elfN(remove_brand_entry)(Elf_Brandinfo *entry); int __elfN(freebsd_fixup)(uintptr_t *, struct image_params *); int __elfN(coredump)(struct thread *, struct vnode *, off_t, int); size_t __elfN(populate_note)(int, void *, void *, size_t, void **); -void __elfN(stackgap)(struct image_params *, uintptr_t *); +vm_size_t __elfN(stackgap)(struct image_params *, uintptr_t *); int __elfN(freebsd_copyout_auxargs)(struct image_params *, uintptr_t); /* Machine specific function to dump per-thread information. */ diff --git a/sys/sys/sysent.h b/sys/sys/sysent.h index 3e87bc7c3744..d95ea5cd9038 100644 --- a/sys/sys/sysent.h +++ b/sys/sys/sysent.h @@ -114,7 +114,7 @@ struct sysentvec { int (*sv_coredump)(struct thread *, struct vnode *, off_t, int); /* function to dump core, or NULL */ int (*sv_imgact_try)(struct image_params *); - void (*sv_stackgap)(struct image_params *, uintptr_t *); + vm_size_t (*sv_stackgap)(struct image_params *, uintptr_t *); int (*sv_copyout_auxargs)(struct image_params *, uintptr_t); int sv_minsigstksz; /* minimum signal stack size */ diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c index 1ac4ccf72f11..87a290b998b9 100644 --- a/sys/vm/vm_map.c +++ b/sys/vm/vm_map.c @@ -343,6 +343,7 @@ vmspace_alloc(vm_offset_t min, vm_offset_t max, pmap_pinit_t pinit) vm->vm_taddr = 0; vm->vm_daddr = 0; vm->vm_maxsaddr = 0; + vm->vm_stkgap = 0; return (vm); } @@ -4265,6 +4266,7 @@ vmspace_fork(struct vmspace *vm1, vm_ooffset_t *fork_charge) vm2->vm_taddr = vm1->vm_taddr; vm2->vm_daddr = vm1->vm_daddr; vm2->vm_maxsaddr = vm1->vm_maxsaddr; + vm2->vm_stkgap = vm1->vm_stkgap; vm_map_lock(old_map); if (old_map->busy) vm_map_wait_busy(old_map); diff --git a/sys/vm/vm_map.h b/sys/vm/vm_map.h index ace205b21b42..873ff62eec4a 100644 --- a/sys/vm/vm_map.h +++ b/sys/vm/vm_map.h @@ -293,6 +293,7 @@ struct vmspace { caddr_t vm_taddr; /* (c) user virtual address of text */ caddr_t vm_daddr; /* (c) user virtual address of data */ caddr_t vm_maxsaddr; /* user VA at max stack growth */ + vm_size_t vm_stkgap; /* stack gap size in bytes */ u_int vm_refcnt; /* number of references */ /* * Keep the PMAP last, so that CPU-specific variations of that
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