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authorLinus Torvalds <torvalds@linux-foundation.org>2017-09-04 11:18:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-04 11:18:17 -0700
commit6c51e67b64d169419fb13318035bb442f9176612 (patch)
treeae6c64a9d703983f9df5f72e74419de2e388e32b /arch/arm64
parente0a195b5225e1285806622cc146dc5c3312fb392 (diff)
parentcf7de27ab35172a9240f079477cae3146a182998 (diff)
downloadlinux-6c51e67b64d169419fb13318035bb442f9176612.tar.bz2
Merge branch 'x86-syscall-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull syscall updates from Ingo Molnar: "Improve the security of set_fs(): we now check the address limit on a number of key platforms (x86, arm, arm64) before returning to user-space - without adding overhead to the typical system call fast path" * 'x86-syscall-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: arm64/syscalls: Check address limit on user-mode return arm/syscalls: Check address limit on user-mode return x86/syscalls: Check address limit on user-mode return
Diffstat (limited to 'arch/arm64')
-rw-r--r--arch/arm64/include/asm/thread_info.h4
-rw-r--r--arch/arm64/include/asm/uaccess.h3
-rw-r--r--arch/arm64/kernel/signal.c5
3 files changed, 11 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 46c3b93cf865..c5ba565544ee 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -86,6 +86,7 @@ struct thread_info {
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
#define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */
#define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */
+#define TIF_FSCHECK 5 /* Check FS is USER_DS on return */
#define TIF_NOHZ 7
#define TIF_SYSCALL_TRACE 8
#define TIF_SYSCALL_AUDIT 9
@@ -107,11 +108,12 @@ struct thread_info {
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_UPROBE (1 << TIF_UPROBE)
+#define _TIF_FSCHECK (1 << TIF_FSCHECK)
#define _TIF_32BIT (1 << TIF_32BIT)
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
_TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
- _TIF_UPROBE)
+ _TIF_UPROBE | _TIF_FSCHECK)
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index fab46a0ea223..a801a48a7972 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -45,6 +45,9 @@ static inline void set_fs(mm_segment_t fs)
{
current_thread_info()->addr_limit = fs;
+ /* On user-mode return, check fs is correct */
+ set_thread_flag(TIF_FSCHECK);
+
/*
* Enable/disable UAO so that copy_to_user() etc can access
* kernel memory with the unprivileged instructions.
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 089c3747995d..e3e3293d1123 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -29,6 +29,7 @@
#include <linux/string.h>
#include <linux/tracehook.h>
#include <linux/ratelimit.h>
+#include <linux/syscalls.h>
#include <asm/debug-monitors.h>
#include <asm/elf.h>
@@ -749,6 +750,10 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
* Update the trace code with the current status.
*/
trace_hardirqs_off();
+
+ /* Check valid user FS if needed */
+ addr_limit_user_check();
+
do {
if (thread_flags & _TIF_NEED_RESCHED) {
schedule();