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-rw-r--r--arch/arm/include/asm/thread_info.h15
-rw-r--r--arch/arm/include/asm/uaccess.h2
-rw-r--r--arch/arm/kernel/entry-common.S9
-rw-r--r--arch/arm/kernel/signal.c5
-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
-rw-r--r--arch/x86/entry/common.c3
-rw-r--r--arch/x86/include/asm/thread_info.h5
-rw-r--r--arch/x86/include/asm/uaccess.h7
-rw-r--r--include/linux/syscalls.h16
11 files changed, 63 insertions, 11 deletions
diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h
index 776757d1604a..1d468b527b7b 100644
--- a/arch/arm/include/asm/thread_info.h
+++ b/arch/arm/include/asm/thread_info.h
@@ -139,10 +139,11 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
#define TIF_NEED_RESCHED 1 /* rescheduling necessary */
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
#define TIF_UPROBE 3 /* breakpointed or singlestepping */
-#define TIF_SYSCALL_TRACE 4 /* syscall trace active */
-#define TIF_SYSCALL_AUDIT 5 /* syscall auditing active */
-#define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */
-#define TIF_SECCOMP 7 /* seccomp syscall filtering active */
+#define TIF_FSCHECK 4 /* Check FS is USER_DS on return */
+#define TIF_SYSCALL_TRACE 5 /* syscall trace active */
+#define TIF_SYSCALL_AUDIT 6 /* syscall auditing active */
+#define TIF_SYSCALL_TRACEPOINT 7 /* syscall tracepoint instrumentation */
+#define TIF_SECCOMP 8 /* seccomp syscall filtering active */
#define TIF_NOHZ 12 /* in adaptive nohz mode */
#define TIF_USING_IWMMXT 17
@@ -153,6 +154,7 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_UPROBE (1 << TIF_UPROBE)
+#define _TIF_FSCHECK (1 << TIF_FSCHECK)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
@@ -166,8 +168,9 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *,
/*
* Change these and you break ASM code in entry-common.S
*/
-#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
- _TIF_NOTIFY_RESUME | _TIF_UPROBE)
+#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
+ _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
+ _TIF_FSCHECK)
#endif /* __KERNEL__ */
#endif /* __ASM_ARM_THREAD_INFO_H */
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 0bf2347495f1..87936dd5d151 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -70,6 +70,8 @@ static inline void set_fs(mm_segment_t fs)
{
current_thread_info()->addr_limit = fs;
modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
+ /* On user-mode return, check fs is correct */
+ set_thread_flag(TIF_FSCHECK);
}
#define segment_eq(a, b) ((a) == (b))
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index eb5cd77bf1d8..e33c32d56193 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -41,7 +41,9 @@ ret_fast_syscall:
UNWIND(.cantunwind )
disable_irq_notrace @ disable interrupts
ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
- tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+ tst r1, #_TIF_SYSCALL_WORK
+ bne fast_work_pending
+ tst r1, #_TIF_WORK_MASK
bne fast_work_pending
/* perform architecture specific actions before user return */
@@ -67,12 +69,15 @@ ret_fast_syscall:
str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
disable_irq_notrace @ disable interrupts
ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
- tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+ tst r1, #_TIF_SYSCALL_WORK
+ bne fast_work_pending
+ tst r1, #_TIF_WORK_MASK
beq no_work_pending
UNWIND(.fnend )
ENDPROC(ret_fast_syscall)
/* Slower path - fall through to work_pending */
+fast_work_pending:
#endif
tst r1, #_TIF_SYSCALL_WORK
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 5814298ef0b7..e2de50bf8742 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -14,6 +14,7 @@
#include <linux/uaccess.h>
#include <linux/tracehook.h>
#include <linux/uprobes.h>
+#include <linux/syscalls.h>
#include <asm/elf.h>
#include <asm/cacheflush.h>
@@ -613,6 +614,10 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
* Update the trace code with the current status.
*/
trace_hardirqs_off();
+
+ /* Check valid user FS if needed */
+ addr_limit_user_check();
+
do {
if (likely(thread_flags & _TIF_NEED_RESCHED)) {
schedule();
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();
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index cdefcfdd9e63..03505ffbe1b6 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -23,6 +23,7 @@
#include <linux/user-return-notifier.h>
#include <linux/uprobes.h>
#include <linux/livepatch.h>
+#include <linux/syscalls.h>
#include <asm/desc.h>
#include <asm/traps.h>
@@ -183,6 +184,8 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
struct thread_info *ti = current_thread_info();
u32 cached_flags;
+ addr_limit_user_check();
+
if (IS_ENABLED(CONFIG_PROVE_LOCKING) && WARN_ON(!irqs_disabled()))
local_irq_disable();
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index e00e1bd6e7b3..5161da1a0fa0 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -98,6 +98,7 @@ struct thread_info {
#define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
#define TIF_ADDR32 29 /* 32-bit address space on 64 bits */
#define TIF_X32 30 /* 32-bit native x86-64 binary */
+#define TIF_FSCHECK 31 /* Check FS is USER_DS on return */
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
@@ -122,6 +123,7 @@ struct thread_info {
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
#define _TIF_ADDR32 (1 << TIF_ADDR32)
#define _TIF_X32 (1 << TIF_X32)
+#define _TIF_FSCHECK (1 << TIF_FSCHECK)
/*
* work to do in syscall_trace_enter(). Also includes TIF_NOHZ for
@@ -137,7 +139,8 @@ struct thread_info {
(_TIF_SYSCALL_TRACE | _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \
_TIF_NEED_RESCHED | _TIF_SINGLESTEP | _TIF_SYSCALL_EMU | \
_TIF_SYSCALL_AUDIT | _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE | \
- _TIF_PATCH_PENDING | _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT)
+ _TIF_PATCH_PENDING | _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT | \
+ _TIF_FSCHECK)
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW \
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 30269dafec47..184eb9894dae 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -26,7 +26,12 @@
#define get_ds() (KERNEL_DS)
#define get_fs() (current->thread.addr_limit)
-#define set_fs(x) (current->thread.addr_limit = (x))
+static inline void set_fs(mm_segment_t fs)
+{
+ current->thread.addr_limit = fs;
+ /* On user-mode return, check fs is correct */
+ set_thread_flag(TIF_FSCHECK);
+}
#define segment_eq(a, b) ((a).seg == (b).seg)
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 138c94535864..d4dfac878fab 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -207,6 +207,22 @@ extern struct trace_event_functions exit_syscall_print_funcs;
} \
static inline long SYSC##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+#ifdef TIF_FSCHECK
+/*
+ * Called before coming back to user-mode. Returning to user-mode with an
+ * address limit different than USER_DS can allow to overwrite kernel memory.
+ */
+static inline void addr_limit_user_check(void)
+{
+
+ if (!test_thread_flag(TIF_FSCHECK))
+ return;
+
+ BUG_ON(!segment_eq(get_fs(), USER_DS));
+ clear_thread_flag(TIF_FSCHECK);
+}
+#endif
+
asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
qid_t id, void __user *addr);
asmlinkage long sys_time(time_t __user *tloc);
generated by cgit v1.2.3 (git 2.39.0) at 2024-12-01 14:00:03 +0300