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-rw-r--r--arch/arm64/kernel/sdei.c2
-rw-r--r--arch/m68k/include/asm/tlbflush.h6
-rw-r--r--arch/mips/kernel/unaligned.c27
-rw-r--r--arch/nds32/mm/alignment.c7
-rw-r--r--arch/sh/kernel/traps_32.c12
-rw-r--r--drivers/firmware/arm_sdei.c5
-rw-r--r--include/linux/uaccess.h18
-rw-r--r--kernel/events/callchain.c5
-rw-r--r--kernel/events/core.c5
-rw-r--r--kernel/kthread.c5
-rw-r--r--kernel/stacktrace.c5
-rw-r--r--mm/maccess.c22
12 files changed, 63 insertions, 56 deletions
diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
index dab88260b137..7689f2031c0c 100644
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c
@@ -180,7 +180,7 @@ static __kprobes unsigned long _sdei_handler(struct pt_regs *regs,
/*
* We didn't take an exception to get here, set PAN. UAO will be cleared
- * by sdei_event_handler()s set_fs(USER_DS) call.
+ * by sdei_event_handler()s force_uaccess_begin() call.
*/
__uaccess_enable_hw_pan();
diff --git a/arch/m68k/include/asm/tlbflush.h b/arch/m68k/include/asm/tlbflush.h
index 191e75a6bb24..5337bc2c262f 100644
--- a/arch/m68k/include/asm/tlbflush.h
+++ b/arch/m68k/include/asm/tlbflush.h
@@ -85,10 +85,10 @@ static inline void flush_tlb_mm(struct mm_struct *mm)
static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
{
if (vma->vm_mm == current->active_mm) {
- mm_segment_t old_fs = get_fs();
- set_fs(USER_DS);
+ mm_segment_t old_fs = force_uaccess_begin();
+
__flush_tlb_one(addr);
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
}
}
diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c
index 0adce604fa44..126a5f3f4e4c 100644
--- a/arch/mips/kernel/unaligned.c
+++ b/arch/mips/kernel/unaligned.c
@@ -191,17 +191,16 @@ static void emulate_load_store_insn(struct pt_regs *regs,
* memory, so we need to "switch" the address limit to
* user space, so that address check can work properly.
*/
- seg = get_fs();
- set_fs(USER_DS);
+ seg = force_uaccess_begin();
switch (insn.spec3_format.func) {
case lhe_op:
if (!access_ok(addr, 2)) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto sigbus;
}
LoadHWE(addr, value, res);
if (res) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto fault;
}
compute_return_epc(regs);
@@ -209,12 +208,12 @@ static void emulate_load_store_insn(struct pt_regs *regs,
break;
case lwe_op:
if (!access_ok(addr, 4)) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto sigbus;
}
LoadWE(addr, value, res);
if (res) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto fault;
}
compute_return_epc(regs);
@@ -222,12 +221,12 @@ static void emulate_load_store_insn(struct pt_regs *regs,
break;
case lhue_op:
if (!access_ok(addr, 2)) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto sigbus;
}
LoadHWUE(addr, value, res);
if (res) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto fault;
}
compute_return_epc(regs);
@@ -235,35 +234,35 @@ static void emulate_load_store_insn(struct pt_regs *regs,
break;
case she_op:
if (!access_ok(addr, 2)) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto sigbus;
}
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreHWE(addr, value, res);
if (res) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto fault;
}
break;
case swe_op:
if (!access_ok(addr, 4)) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto sigbus;
}
compute_return_epc(regs);
value = regs->regs[insn.spec3_format.rt];
StoreWE(addr, value, res);
if (res) {
- set_fs(seg);
+ force_uaccess_end(seg);
goto fault;
}
break;
default:
- set_fs(seg);
+ force_uaccess_end(seg);
goto sigill;
}
- set_fs(seg);
+ force_uaccess_end(seg);
}
#endif
break;
diff --git a/arch/nds32/mm/alignment.c b/arch/nds32/mm/alignment.c
index c8b9061a2ee3..1eb7ded6992b 100644
--- a/arch/nds32/mm/alignment.c
+++ b/arch/nds32/mm/alignment.c
@@ -512,7 +512,7 @@ int do_unaligned_access(unsigned long addr, struct pt_regs *regs)
{
unsigned long inst;
int ret = -EFAULT;
- mm_segment_t seg = get_fs();
+ mm_segment_t seg;
inst = get_inst(regs->ipc);
@@ -520,13 +520,12 @@ int do_unaligned_access(unsigned long addr, struct pt_regs *regs)
"Faulting addr: 0x%08lx, pc: 0x%08lx [inst: 0x%08lx ]\n", addr,
regs->ipc, inst);
- set_fs(USER_DS);
-
+ seg = force_uaccess_begin();
if (inst & NDS32_16BIT_INSTRUCTION)
ret = do_16((inst >> 16) & 0xffff, regs);
else
ret = do_32(inst, regs);
- set_fs(seg);
+ force_uaccess_end(seg);
return ret;
}
diff --git a/arch/sh/kernel/traps_32.c b/arch/sh/kernel/traps_32.c
index 058c6181bb30..b62ad0ba2395 100644
--- a/arch/sh/kernel/traps_32.c
+++ b/arch/sh/kernel/traps_32.c
@@ -482,8 +482,6 @@ asmlinkage void do_address_error(struct pt_regs *regs,
error_code = lookup_exception_vector();
#endif
- oldfs = get_fs();
-
if (user_mode(regs)) {
int si_code = BUS_ADRERR;
unsigned int user_action;
@@ -491,13 +489,13 @@ asmlinkage void do_address_error(struct pt_regs *regs,
local_irq_enable();
inc_unaligned_user_access();
- set_fs(USER_DS);
+ oldfs = force_uaccess_begin();
if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
sizeof(instruction))) {
- set_fs(oldfs);
+ force_uaccess_end(oldfs);
goto uspace_segv;
}
- set_fs(oldfs);
+ force_uaccess_end(oldfs);
/* shout about userspace fixups */
unaligned_fixups_notify(current, instruction, regs);
@@ -520,11 +518,11 @@ fixup:
goto uspace_segv;
}
- set_fs(USER_DS);
+ oldfs = force_uaccess_begin();
tmp = handle_unaligned_access(instruction, regs,
&user_mem_access, 0,
address);
- set_fs(oldfs);
+ force_uaccess_end(oldfs);
if (tmp == 0)
return; /* sorted */
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
index e7e36aab2386..b4b9ce97f415 100644
--- a/drivers/firmware/arm_sdei.c
+++ b/drivers/firmware/arm_sdei.c
@@ -1136,15 +1136,14 @@ int sdei_event_handler(struct pt_regs *regs,
* access kernel memory.
* Do the same here because this doesn't come via the same entry code.
*/
- orig_addr_limit = get_fs();
- set_fs(USER_DS);
+ orig_addr_limit = force_uaccess_begin();
err = arg->callback(event_num, regs, arg->callback_arg);
if (err)
pr_err_ratelimited("event %u on CPU %u failed with error: %d\n",
event_num, smp_processor_id(), err);
- set_fs(orig_addr_limit);
+ force_uaccess_end(orig_addr_limit);
return err;
}
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 5c62d0c6f15b..94b285411659 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -9,6 +9,24 @@
#include <asm/uaccess.h>
/*
+ * Force the uaccess routines to be wired up for actual userspace access,
+ * overriding any possible set_fs(KERNEL_DS) still lingering around. Undone
+ * using force_uaccess_end below.
+ */
+static inline mm_segment_t force_uaccess_begin(void)
+{
+ mm_segment_t fs = get_fs();
+
+ set_fs(USER_DS);
+ return fs;
+}
+
+static inline void force_uaccess_end(mm_segment_t oldfs)
+{
+ set_fs(oldfs);
+}
+
+/*
* Architectures should provide two primitives (raw_copy_{to,from}_user())
* and get rid of their private instances of copy_{to,from}_user() and
* __copy_{to,from}_user{,_inatomic}().
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index c6ce894e4ce9..58cbe357fb2b 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -217,10 +217,9 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
if (add_mark)
perf_callchain_store_context(&ctx, PERF_CONTEXT_USER);
- fs = get_fs();
- set_fs(USER_DS);
+ fs = force_uaccess_begin();
perf_callchain_user(&ctx, regs);
- set_fs(fs);
+ force_uaccess_end(fs);
}
}
diff --git a/kernel/events/core.c b/kernel/events/core.c
index d1f0a7e5b182..6961333ebad5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6453,10 +6453,9 @@ perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
/* Data. */
sp = perf_user_stack_pointer(regs);
- fs = get_fs();
- set_fs(USER_DS);
+ fs = force_uaccess_begin();
rem = __output_copy_user(handle, (void *) sp, dump_size);
- set_fs(fs);
+ force_uaccess_end(fs);
dyn_size = dump_size - rem;
perf_output_skip(handle, rem);
diff --git a/kernel/kthread.c b/kernel/kthread.c
index b2807e7be772..3edaa380dc7b 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -1258,8 +1258,7 @@ void kthread_use_mm(struct mm_struct *mm)
if (active_mm != mm)
mmdrop(active_mm);
- to_kthread(tsk)->oldfs = get_fs();
- set_fs(USER_DS);
+ to_kthread(tsk)->oldfs = force_uaccess_begin();
}
EXPORT_SYMBOL_GPL(kthread_use_mm);
@@ -1274,7 +1273,7 @@ void kthread_unuse_mm(struct mm_struct *mm)
WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD));
WARN_ON_ONCE(!tsk->mm);
- set_fs(to_kthread(tsk)->oldfs);
+ force_uaccess_end(to_kthread(tsk)->oldfs);
task_lock(tsk);
sync_mm_rss(mm);
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 2af66e449aa6..946f44a9e86a 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -233,10 +233,9 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
if (current->flags & PF_KTHREAD)
return 0;
- fs = get_fs();
- set_fs(USER_DS);
+ fs = force_uaccess_begin();
arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
- set_fs(fs);
+ force_uaccess_end(fs);
return c.len;
}
diff --git a/mm/maccess.c b/mm/maccess.c
index f98ff91e32c6..3bd70405f2d8 100644
--- a/mm/maccess.c
+++ b/mm/maccess.c
@@ -205,15 +205,14 @@ long strncpy_from_kernel_nofault(char *dst, const void *unsafe_addr, long count)
long copy_from_user_nofault(void *dst, const void __user *src, size_t size)
{
long ret = -EFAULT;
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs = force_uaccess_begin();
- set_fs(USER_DS);
if (access_ok(src, size)) {
pagefault_disable();
ret = __copy_from_user_inatomic(dst, src, size);
pagefault_enable();
}
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
if (ret)
return -EFAULT;
@@ -233,15 +232,14 @@ EXPORT_SYMBOL_GPL(copy_from_user_nofault);
long copy_to_user_nofault(void __user *dst, const void *src, size_t size)
{
long ret = -EFAULT;
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs = force_uaccess_begin();
- set_fs(USER_DS);
if (access_ok(dst, size)) {
pagefault_disable();
ret = __copy_to_user_inatomic(dst, src, size);
pagefault_enable();
}
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
if (ret)
return -EFAULT;
@@ -270,17 +268,17 @@ EXPORT_SYMBOL_GPL(copy_to_user_nofault);
long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
long count)
{
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs;
long ret;
if (unlikely(count <= 0))
return 0;
- set_fs(USER_DS);
+ old_fs = force_uaccess_begin();
pagefault_disable();
ret = strncpy_from_user(dst, unsafe_addr, count);
pagefault_enable();
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
if (ret >= count) {
ret = count;
@@ -310,14 +308,14 @@ long strncpy_from_user_nofault(char *dst, const void __user *unsafe_addr,
*/
long strnlen_user_nofault(const void __user *unsafe_addr, long count)
{
- mm_segment_t old_fs = get_fs();
+ mm_segment_t old_fs;
int ret;
- set_fs(USER_DS);
+ old_fs = force_uaccess_begin();
pagefault_disable();
ret = strnlen_user(unsafe_addr, count);
pagefault_enable();
- set_fs(old_fs);
+ force_uaccess_end(old_fs);
return ret;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-28 23:05:02 +0000