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| author | Thomas Garnier <thgarnie@google.com> | 2017-06-14 18:12:03 -0700 |
|---|---|---|
| committer | Amit Pundir <amit.pundir@linaro.org> | 2018-10-04 14:20:05 +0530 |
| commit | 335f7b933d66e29a512f952880c52bd4e0f50a62 (patch) | |
| tree | 22595a696d7b025036b0a93c6fa3f6ac5842daa3 | |
| parent | 4ac94c62b18065514a02c0664da92a6832014c80 (diff) | |
| download | linaro-android-335f7b933d66e29a512f952880c52bd4e0f50a62.tar.gz | |
BACKPORT: arm64/syscalls: Check address limit on user-mode return
(cherry-picked from cf7de27ab35172a9240f079477cae3146a182998)
Ensure the address limit is a user-mode segment before returning to
user-mode. Otherwise a process can corrupt kernel-mode memory and
elevate privileges [1].
The set_fs function sets the TIF_SETFS flag to force a slow path on
return. In the slow path, the address limit is checked to be USER_DS if
needed.
[1] https://bugs.chromium.org/p/project-zero/issues/detail?id=990
Change-Id: Ic0e917286d7378cb26c15a7e553ef56fabb2f543
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: kernel-hardening@lists.openwall.com
Cc: Will Deacon <will.deacon@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Pratyush Anand <panand@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Drewry <wad@chromium.org>
Cc: linux-api@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Link: http://lkml.kernel.org/r/20170615011203.144108-3-thgarnie@google.com
Signed-off-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
| -rw-r--r-- | arch/arm64/include/asm/thread_info.h | 5 | ||||
| -rw-r--r-- | arch/arm64/include/asm/uaccess.h | 3 | ||||
| -rw-r--r-- | arch/arm64/kernel/signal.c | 4 |
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 67dd228c3f17..8c22d1618260 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -120,6 +120,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_NEED_RESCHED 1 #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_FSCHECK 4 /* Check FS is USER_DS on return */ #define TIF_NOHZ 7 #define TIF_SYSCALL_TRACE 8 #define TIF_SYSCALL_AUDIT 9 @@ -140,10 +141,12 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) #define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT) #define _TIF_SECCOMP (1 << TIF_SECCOMP) +#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_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \ + _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 d39d8bde42d7..d0919bcb1953 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -73,6 +73,9 @@ 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 a8eafdbc7cb8..0bed9a899850 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -25,6 +25,7 @@ #include <linux/uaccess.h> #include <linux/tracehook.h> #include <linux/ratelimit.h> +#include <linux/syscalls.h> #include <asm/debug-monitors.h> #include <asm/elf.h> @@ -402,6 +403,9 @@ static void do_signal(struct pt_regs *regs) asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int thread_flags) { + /* Check valid user FS if needed */ + addr_limit_user_check(); + if (thread_flags & _TIF_SIGPENDING) do_signal(regs); |