generic ...copy_..._user primitives
provide raw_copy_..._user() and select ARCH_HAS_RAW_COPY_USER to use those. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
parent
c1aad8dcc4
commit
d597580d37
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@ -847,4 +847,7 @@ config STRICT_MODULE_RWX
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config ARCH_WANT_RELAX_ORDER
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config ARCH_WANT_RELAX_ORDER
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bool
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bool
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config ARCH_HAS_RAW_COPY_USER
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bool
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source "kernel/gcov/Kconfig"
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source "kernel/gcov/Kconfig"
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@ -86,7 +86,11 @@ static inline int __access_ok(unsigned long addr, unsigned long size)
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static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
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static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
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{
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{
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#ifdef CONFIG_ARCH_HAS_RAW_COPY_USER
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return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0;
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#else
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return unlikely(__copy_to_user(ptr, x, size)) ? -EFAULT : 0;
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return unlikely(__copy_to_user(ptr, x, size)) ? -EFAULT : 0;
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#endif
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}
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}
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#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
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#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
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@ -147,7 +151,11 @@ extern int __put_user_bad(void) __attribute__((noreturn));
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#ifndef __get_user_fn
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#ifndef __get_user_fn
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static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
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static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
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{
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{
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#ifdef CONFIG_ARCH_HAS_RAW_COPY_USER
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return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0;
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#else
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return unlikely(__copy_from_user(x, ptr, size)) ? -EFAULT : 0;
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return unlikely(__copy_from_user(x, ptr, size)) ? -EFAULT : 0;
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#endif
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}
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}
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#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
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#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
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@ -156,6 +164,8 @@ static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
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extern int __get_user_bad(void) __attribute__((noreturn));
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extern int __get_user_bad(void) __attribute__((noreturn));
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#ifndef CONFIG_ARCH_HAS_RAW_COPY_USER
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#ifndef __copy_from_user_inatomic
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#ifndef __copy_from_user_inatomic
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#define __copy_from_user_inatomic __copy_from_user
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#define __copy_from_user_inatomic __copy_from_user
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#endif
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#endif
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@ -185,6 +195,7 @@ static inline long copy_to_user(void __user *to,
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else
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else
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return n;
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return n;
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}
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}
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#endif
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/*
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/*
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* Copy a null terminated string from userspace.
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* Copy a null terminated string from userspace.
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@ -3,6 +3,7 @@
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#include <linux/sched.h>
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#include <linux/sched.h>
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#include <linux/thread_info.h>
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#include <linux/thread_info.h>
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#include <linux/kasan-checks.h>
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#define VERIFY_READ 0
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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#define VERIFY_WRITE 1
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@ -11,6 +12,192 @@
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#include <asm/uaccess.h>
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#include <asm/uaccess.h>
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#ifdef CONFIG_ARCH_HAS_RAW_COPY_USER
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/*
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* Architectures should provide two primitives (raw_copy_{to,from}_user())
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* select ARCH_HAS_RAW_COPY_FROM_USER and get rid of their private instances
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* of copy_{to,from}_user() and __copy_{to,from}_user{,_inatomic}(). Once
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* all of them switch, this part of linux/uaccess.h will become unconditional.
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*
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* raw_copy_{to,from}_user(to, from, size) should copy up to size bytes and
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* return the amount left to copy. They should assume that access_ok() has
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* already been checked (and succeeded); they should *not* zero-pad anything.
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* No KASAN or object size checks either - those belong here.
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*
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* Both of these functions should attempt to copy size bytes starting at from
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* into the area starting at to. They must not fetch or store anything
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* outside of those areas. Return value must be between 0 (everything
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* copied successfully) and size (nothing copied).
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*
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* If raw_copy_{to,from}_user(to, from, size) returns N, size - N bytes starting
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* at to must become equal to the bytes fetched from the corresponding area
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* starting at from. All data past to + size - N must be left unmodified.
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*
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* If copying succeeds, the return value must be 0. If some data cannot be
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* fetched, it is permitted to copy less than had been fetched; the only
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* hard requirement is that not storing anything at all (i.e. returning size)
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* should happen only when nothing could be copied. In other words, you don't
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* have to squeeze as much as possible - it is allowed, but not necessary.
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*
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* For raw_copy_from_user() to always points to kernel memory and no faults
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* on store should happen. Interpretation of from is affected by set_fs().
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* For raw_copy_to_user() it's the other way round.
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*
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* Both can be inlined - it's up to architectures whether it wants to bother
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* with that. They should not be used directly; they are used to implement
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* the 6 functions (copy_{to,from}_user(), __copy_{to,from}_user_inatomic())
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* that are used instead. Out of those, __... ones are inlined. Plain
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* copy_{to,from}_user() might or might not be inlined. If you want them
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* inlined, have asm/uaccess.h define INLINE_COPY_{TO,FROM}_USER.
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*
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* NOTE: only copy_from_user() zero-pads the destination in case of short copy.
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* Neither __copy_from_user() nor __copy_from_user_inatomic() zero anything
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* at all; their callers absolutely must check the return value.
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*
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* Biarch ones should also provide raw_copy_in_user() - similar to the above,
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* but both source and destination are __user pointers (affected by set_fs()
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* as usual) and both source and destination can trigger faults.
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*/
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static __always_inline unsigned long
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__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
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{
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kasan_check_write(to, n);
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check_object_size(to, n, false);
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return raw_copy_from_user(to, from, n);
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}
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static __always_inline unsigned long
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__copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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might_fault();
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kasan_check_write(to, n);
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check_object_size(to, n, false);
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return raw_copy_from_user(to, from, n);
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}
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/**
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* __copy_to_user_inatomic: - Copy a block of data into user space, with less checking.
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* @to: Destination address, in user space.
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* @from: Source address, in kernel space.
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* @n: Number of bytes to copy.
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*
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* Context: User context only.
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*
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* Copy data from kernel space to user space. Caller must check
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* the specified block with access_ok() before calling this function.
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* The caller should also make sure he pins the user space address
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* so that we don't result in page fault and sleep.
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*/
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static __always_inline unsigned long
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__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
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{
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kasan_check_read(from, n);
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check_object_size(from, n, true);
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return raw_copy_to_user(to, from, n);
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}
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static __always_inline unsigned long
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__copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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might_fault();
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kasan_check_read(from, n);
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check_object_size(from, n, true);
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return raw_copy_to_user(to, from, n);
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}
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#ifdef INLINE_COPY_FROM_USER
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static inline unsigned long
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_copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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unsigned long res = n;
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if (likely(access_ok(VERIFY_READ, from, n)))
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res = raw_copy_from_user(to, from, n);
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if (unlikely(res))
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memset(to + (n - res), 0, res);
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return res;
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}
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#else
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extern unsigned long
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_copy_from_user(void *, const void __user *, unsigned long);
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#endif
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#ifdef INLINE_COPY_TO_USER
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static inline unsigned long
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_copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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if (access_ok(VERIFY_WRITE, to, n))
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n = raw_copy_to_user(to, from, n);
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return n;
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}
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#else
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extern unsigned long
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_copy_to_user(void __user *, const void *, unsigned long);
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#endif
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extern void __compiletime_error("usercopy buffer size is too small")
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__bad_copy_user(void);
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static inline void copy_user_overflow(int size, unsigned long count)
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{
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WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
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}
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static __always_inline unsigned long __must_check
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copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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int sz = __compiletime_object_size(to);
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might_fault();
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kasan_check_write(to, n);
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if (likely(sz < 0 || sz >= n)) {
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check_object_size(to, n, false);
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n = _copy_from_user(to, from, n);
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} else if (!__builtin_constant_p(n))
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copy_user_overflow(sz, n);
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else
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__bad_copy_user();
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return n;
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}
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static __always_inline unsigned long __must_check
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copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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int sz = __compiletime_object_size(from);
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kasan_check_read(from, n);
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might_fault();
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if (likely(sz < 0 || sz >= n)) {
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check_object_size(from, n, true);
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n = _copy_to_user(to, from, n);
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} else if (!__builtin_constant_p(n))
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copy_user_overflow(sz, n);
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else
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__bad_copy_user();
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return n;
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}
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#ifdef CONFIG_COMPAT
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static __always_inline unsigned long __must_check
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__copy_in_user(void __user *to, const void *from, unsigned long n)
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{
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might_fault();
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return raw_copy_in_user(to, from, n);
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}
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static __always_inline unsigned long __must_check
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copy_in_user(void __user *to, const void *from, unsigned long n)
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{
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might_fault();
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if (access_ok(VERIFY_WRITE, to, n) && access_ok(VERIFY_READ, from, n))
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n = raw_copy_in_user(to, from, n);
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return n;
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}
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#endif
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#endif
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static __always_inline void pagefault_disabled_inc(void)
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static __always_inline void pagefault_disabled_inc(void)
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{
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{
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current->pagefault_disabled++;
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current->pagefault_disabled++;
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@ -242,3 +242,5 @@ UBSAN_SANITIZE_ubsan.o := n
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obj-$(CONFIG_SBITMAP) += sbitmap.o
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obj-$(CONFIG_SBITMAP) += sbitmap.o
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obj-$(CONFIG_PARMAN) += parman.o
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obj-$(CONFIG_PARMAN) += parman.o
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obj-$(CONFIG_ARCH_HAS_RAW_COPY_USER) += usercopy.o
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@ -0,0 +1,26 @@
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#include <linux/uaccess.h>
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/* out-of-line parts */
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#ifndef INLINE_COPY_FROM_USER
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unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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unsigned long res = n;
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if (likely(access_ok(VERIFY_READ, from, n)))
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res = raw_copy_from_user(to, from, n);
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if (unlikely(res))
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memset(to + (n - res), 0, res);
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return res;
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}
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EXPORT_SYMBOL(_copy_from_user);
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#endif
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#ifndef INLINE_COPY_TO_USER
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unsigned long _copy_to_user(void *to, const void __user *from, unsigned long n)
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{
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if (likely(access_ok(VERIFY_WRITE, to, n)))
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n = raw_copy_to_user(to, from, n);
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return n;
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}
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EXPORT_SYMBOL(_copy_to_user);
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#endif
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