Re: git: 800da341bc4a - main - thread: Simplify sanitizer integration with thread creation
Date: Mon, 22 Apr 2024 17:06:31 UTC
Am Mon, 22 Apr 2024 15:54:27 GMT
Mark Johnston <markj@FreeBSD.org> schrieb:
> The branch main has been updated by markj:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=800da341bc4a35f4b4d82d104b130825d9a42ffa
>
> commit 800da341bc4a35f4b4d82d104b130825d9a42ffa
> Author: Mark Johnston <markj@FreeBSD.org>
> AuthorDate: 2024-04-22 15:43:17 +0000
> Commit: Mark Johnston <markj@FreeBSD.org>
> CommitDate: 2024-04-22 15:46:59 +0000
>
> thread: Simplify sanitizer integration with thread creation
>
> fork() may allocate a new thread in one of two ways: from UMA, or cached
> in a freed proc that was just allocated from UMA. In either case, KASAN
> and KMSAN need to initialize some state; in particular they need to
> initialize the shadow mapping of the new thread's stack.
>
> This is done differently between KASAN and KMSAN, which is confusing.
> This patch improves things a bit:
> - Add a new thread_recycle() function, which moves all kernel stack
> handling out of kern_fork.c, since it doesn't really belong there.
> - Then, thread_alloc_stack() has only one local caller, so just inline
> it.
> - Avoid redundant shadow stack initialization: thread_alloc()
> initializes the KMSAN shadow stack (via kmsan_thread_alloc()) even
> through vm_thread_new() already did that.
> - Add kasan_thread_alloc(), for consistency with kmsan_thread_alloc().
>
> No functional change intended.
>
> Reviewed by: khng
> MFC after: 1 week
> Differential Revision: https://reviews.freebsd.org/D44891
> ---
> sys/kern/kern_fork.c | 17 +++--------------
> sys/kern/kern_thread.c | 20 ++++++++++++--------
> sys/kern/subr_asan.c | 10 ++++++++++
> sys/sys/asan.h | 4 ++++
> sys/sys/proc.h | 2 +-
> sys/vm/vm_glue.c | 9 ++++-----
> 6 files changed, 34 insertions(+), 28 deletions(-)
>
> diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
> index d0044dfc19a0..41f6a76c4fa1 100644
> --- a/sys/kern/kern_fork.c
> +++ b/sys/kern/kern_fork.c
> @@ -40,7 +40,6 @@
>
> #include <sys/param.h>
> #include <sys/systm.h>
> -#include <sys/asan.h>
> #include <sys/bitstring.h>
> #include <sys/sysproto.h>
> #include <sys/eventhandler.h>
> @@ -1019,19 +1018,9 @@ fork1(struct thread *td, struct fork_req *fr)
> }
> proc_linkup(newproc, td2);
> } else {
> - kmsan_thread_alloc(td2);
> - if (td2->td_kstack == 0 || td2->td_kstack_pages != pages) {
> - if (td2->td_kstack != 0)
> - vm_thread_dispose(td2);
> - if (!thread_alloc_stack(td2, pages)) {
> - error = ENOMEM;
> - goto fail2;
> - }
> - } else {
> - kasan_mark((void *)td2->td_kstack,
> - ptoa(td2->td_kstack_pages),
> - ptoa(td2->td_kstack_pages), 0);
> - }
> + error = thread_recycle(td2, pages);
> + if (error != 0)
> + goto fail2;
> }
>
> if ((flags & RFMEM) == 0) {
> diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c
> index 0bcd5c2f2add..725791769ac3 100644
> --- a/sys/kern/kern_thread.c
> +++ b/sys/kern/kern_thread.c
> @@ -798,6 +798,7 @@ thread_alloc(int pages)
> }
> td->td_tid = tid;
> bzero(&td->td_sa.args, sizeof(td->td_sa.args));
> + kasan_thread_alloc(td);
> kmsan_thread_alloc(td);
> cpu_thread_alloc(td);
> EVENTHANDLER_DIRECT_INVOKE(thread_ctor, td);
> @@ -805,15 +806,18 @@ thread_alloc(int pages)
> }
>
> int
> -thread_alloc_stack(struct thread *td, int pages)
> +thread_recycle(struct thread *td, int pages)
> {
> -
> - KASSERT(td->td_kstack == 0,
> - ("thread_alloc_stack called on a thread with kstack"));
> - if (!vm_thread_new(td, pages))
> - return (0);
> - cpu_thread_alloc(td);
> - return (1);
> + if (td->td_kstack == 0 || td->td_kstack_pages != pages) {
> + if (td->td_kstack != 0)
> + vm_thread_dispose(td);
> + if (!vm_thread_new(td, pages))
> + return (ENOMEM);
> + cpu_thread_alloc(td);
> + }
> + kasan_thread_alloc(td);
> + kmsan_thread_alloc(td);
> + return (0);
> }
>
> /*
> diff --git a/sys/kern/subr_asan.c b/sys/kern/subr_asan.c
> index c3664d9cf6c2..75d9e75c531a 100644
> --- a/sys/kern/subr_asan.c
> +++ b/sys/kern/subr_asan.c
> @@ -39,6 +39,7 @@ __KERNEL_RCSID(0, "$NetBSD: subr_asan.c,v 1.26 2020/09/10 14:10:46 maxv
> Exp $"); #include <sys/systm.h>
> #include <sys/asan.h>
> #include <sys/kernel.h>
> +#include <sys/proc.h>
> #include <sys/stack.h>
> #include <sys/sysctl.h>
>
> @@ -294,6 +295,15 @@ kasan_mark(const void *addr, size_t size, size_t redzsize, uint8_t code)
> }
> }
>
> +void
> +kasan_thread_alloc(struct thread *td)
> +{
> + if (td->td_kstack != 0) {
> + kasan_mark((void *)td->td_kstack, ptoa(td->td_kstack_pages),
> + ptoa(td->td_kstack_pages), 0);
> + }
> +}
> +
> /* -------------------------------------------------------------------------- */
>
> #define ADDR_CROSSES_SCALE_BOUNDARY(addr, size) \
> diff --git a/sys/sys/asan.h b/sys/sys/asan.h
> index a3becdef5f57..6a01d0531725 100644
> --- a/sys/sys/asan.h
> +++ b/sys/sys/asan.h
> @@ -53,14 +53,18 @@
> #define KASAN_KSTACK_FREED 0xFE
> #define KASAN_EXEC_ARGS_FREED 0xFF
>
> +struct thread;
> +
> void kasan_init(void);
> void kasan_init_early(vm_offset_t, size_t);
> void kasan_shadow_map(vm_offset_t, size_t);
> void kasan_mark(const void *, size_t, size_t, uint8_t);
> +void kasan_thread_alloc(struct thread *);
> #else /* KASAN */
> #define kasan_init()
> #define kasan_shadow_map(a, s)
> #define kasan_mark(p, s, l, c)
> +#define kasan_thread_alloc(t)
> #endif /* !KASAN */
>
> #endif /* !_SYS_ASAN_H_ */
> diff --git a/sys/sys/proc.h b/sys/sys/proc.h
> index 33b836f4150e..1b542d1374b4 100644
> --- a/sys/sys/proc.h
> +++ b/sys/sys/proc.h
> @@ -1262,7 +1262,6 @@ void cpu_thread_free(struct thread *);
> void cpu_thread_swapin(struct thread *);
> void cpu_thread_swapout(struct thread *);
> struct thread *thread_alloc(int pages);
> -int thread_alloc_stack(struct thread *, int pages);
> int thread_check_susp(struct thread *td, bool sleep);
> void thread_cow_get_proc(struct thread *newtd, struct proc *p);
> void thread_cow_get(struct thread *newtd, struct thread *td);
> @@ -1275,6 +1274,7 @@ void thread_exit(void) __dead2;
> void thread_free(struct thread *td);
> void thread_link(struct thread *td, struct proc *p);
> void thread_reap_barrier(void);
> +int thread_recycle(struct thread *, int pages);
> int thread_single(struct proc *p, int how);
> void thread_single_end(struct proc *p, int how);
> void thread_stash(struct thread *td);
> diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c
> index 4292a7533503..f9235fe03fab 100644
> --- a/sys/vm/vm_glue.c
> +++ b/sys/vm/vm_glue.c
> @@ -543,8 +543,6 @@ vm_thread_new(struct thread *td, int pages)
> td->td_kstack = ks;
> td->td_kstack_pages = pages;
> td->td_kstack_domain = ks_domain;
> - kasan_mark((void *)ks, ptoa(pages), ptoa(pages), 0);
> - kmsan_mark((void *)ks, ptoa(pages), KMSAN_STATE_UNINIT);
> return (1);
> }
>
> @@ -562,11 +560,12 @@ vm_thread_dispose(struct thread *td)
> td->td_kstack = 0;
> td->td_kstack_pages = 0;
> td->td_kstack_domain = MAXMEMDOM;
> - kasan_mark((void *)ks, 0, ptoa(pages), KASAN_KSTACK_FREED);
> - if (pages == kstack_pages)
> + if (pages == kstack_pages) {
> + kasan_mark((void *)ks, 0, ptoa(pages), KASAN_KSTACK_FREED);
> uma_zfree(kstack_cache, (void *)ks);
> - else
> + } else {
> vm_thread_stack_dispose(ks, pages);
> + }
> }
>
> /*
>
It seems to me that this commit breaks make buildkernel:
[...]
===> accf_dns (all)
--- kern_thread.o ---
/usr/src/sys/kern/kern_thread.c:801:2: error: call to undeclared function
'kasan_thread_alloc'; ISO C99 and later do not support implicit function declarations
[-Werror,-Wimplicit-function-declaration] 801 | kasan_thread_alloc(td); | ^
/usr/src/sys/kern/kern_thread.c:818:2: error: call to undeclared function
'kasan_thread_alloc'; ISO C99 and later do not support implicit function declarations
[-Werror,-Wimplicit-function-declaration] --- modules-all --- --- all_subdir_accf_http ---
===> accf_http (all)
--- kern_thread.o ---
818 | kasan_thread_alloc(td);
| ^
2 errors generated.
Kind regards,
oh
--
O. Hartmann