Merge tag 'kvm-x86-generic-6.5' of https://github.com/kvm-x86/linux into HEAD
[linux-2.6-microblaze.git] / lib / iov_iter.c
index 274014e..960223e 100644 (file)
@@ -126,13 +126,13 @@ __out:                                                            \
                        iterate_buf(i, n, base, len, off,       \
                                                i->ubuf, (I))   \
                } else if (likely(iter_is_iovec(i))) {          \
-                       const struct iovec *iov = i->iov;       \
+                       const struct iovec *iov = iter_iov(i);  \
                        void __user *base;                      \
                        size_t len;                             \
                        iterate_iovec(i, n, base, len, off,     \
                                                iov, (I))       \
-                       i->nr_segs -= iov - i->iov;             \
-                       i->iov = iov;                           \
+                       i->nr_segs -= iov - iter_iov(i);        \
+                       i->__iov = iov;                         \
                } else if (iov_iter_is_bvec(i)) {               \
                        const struct bio_vec *bvec = i->bvec;   \
                        void *base;                             \
@@ -172,6 +172,18 @@ static int copyout(void __user *to, const void *from, size_t n)
        return n;
 }
 
+static int copyout_nofault(void __user *to, const void *from, size_t n)
+{
+       long res;
+
+       if (should_fail_usercopy())
+               return n;
+
+       res = copy_to_user_nofault(to, from, n);
+
+       return res < 0 ? n : res;
+}
+
 static int copyin(void *to, const void __user *from, size_t n)
 {
        size_t res = n;
@@ -355,7 +367,7 @@ size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size)
                size_t skip;
 
                size -= count;
-               for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) {
+               for (p = iter_iov(i), skip = i->iov_offset; count; p++, skip = 0) {
                        size_t len = min(count, p->iov_len - skip);
                        size_t ret;
 
@@ -398,7 +410,7 @@ size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size)
                size_t skip;
 
                size -= count;
-               for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) {
+               for (p = iter_iov(i), skip = i->iov_offset; count; p++, skip = 0) {
                        size_t len = min(count, p->iov_len - skip);
                        size_t ret;
 
@@ -422,10 +434,11 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction,
        WARN_ON(direction & ~(READ | WRITE));
        *i = (struct iov_iter) {
                .iter_type = ITER_IOVEC,
+               .copy_mc = false,
                .nofault = false,
                .user_backed = true,
                .data_source = direction,
-               .iov = iov,
+               .__iov = iov,
                .nr_segs = nr_segs,
                .iov_offset = 0,
                .count = count
@@ -618,6 +631,14 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 EXPORT_SYMBOL_GPL(_copy_mc_to_iter);
 #endif /* CONFIG_ARCH_HAS_COPY_MC */
 
+static void *memcpy_from_iter(struct iov_iter *i, void *to, const void *from,
+                                size_t size)
+{
+       if (iov_iter_is_copy_mc(i))
+               return (void *)copy_mc_to_kernel(to, from, size);
+       return memcpy(to, from, size);
+}
+
 size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
        if (WARN_ON_ONCE(!i->data_source))
@@ -627,7 +648,7 @@ size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
                might_fault();
        iterate_and_advance(i, bytes, base, len, off,
                copyin(addr + off, base, len),
-               memcpy(addr + off, base, len)
+               memcpy_from_iter(i, addr + off, base, len)
        )
 
        return bytes;
@@ -734,6 +755,42 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
 }
 EXPORT_SYMBOL(copy_page_to_iter);
 
+size_t copy_page_to_iter_nofault(struct page *page, unsigned offset, size_t bytes,
+                                struct iov_iter *i)
+{
+       size_t res = 0;
+
+       if (!page_copy_sane(page, offset, bytes))
+               return 0;
+       if (WARN_ON_ONCE(i->data_source))
+               return 0;
+       if (unlikely(iov_iter_is_pipe(i)))
+               return copy_page_to_iter_pipe(page, offset, bytes, i);
+       page += offset / PAGE_SIZE; // first subpage
+       offset %= PAGE_SIZE;
+       while (1) {
+               void *kaddr = kmap_local_page(page);
+               size_t n = min(bytes, (size_t)PAGE_SIZE - offset);
+
+               iterate_and_advance(i, n, base, len, off,
+                       copyout_nofault(base, kaddr + offset + off, len),
+                       memcpy(base, kaddr + offset + off, len)
+               )
+               kunmap_local(kaddr);
+               res += n;
+               bytes -= n;
+               if (!bytes || !n)
+                       break;
+               offset += n;
+               if (offset == PAGE_SIZE) {
+                       page++;
+                       offset = 0;
+               }
+       }
+       return res;
+}
+EXPORT_SYMBOL(copy_page_to_iter_nofault);
+
 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
                         struct iov_iter *i)
 {
@@ -814,7 +871,7 @@ size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t byt
        }
        iterate_and_advance(i, bytes, base, len, off,
                copyin(p + off, base, len),
-               memcpy(p + off, base, len)
+               memcpy_from_iter(i, p + off, base, len)
        )
        kunmap_atomic(kaddr);
        return bytes;
@@ -876,14 +933,14 @@ static void iov_iter_iovec_advance(struct iov_iter *i, size_t size)
        i->count -= size;
 
        size += i->iov_offset; // from beginning of current segment
-       for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) {
+       for (iov = iter_iov(i), end = iov + i->nr_segs; iov < end; iov++) {
                if (likely(size < iov->iov_len))
                        break;
                size -= iov->iov_len;
        }
        i->iov_offset = size;
-       i->nr_segs -= iov - i->iov;
-       i->iov = iov;
+       i->nr_segs -= iov - iter_iov(i);
+       i->__iov = iov;
 }
 
 void iov_iter_advance(struct iov_iter *i, size_t size)
@@ -958,12 +1015,12 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
                        unroll -= n;
                }
        } else { /* same logics for iovec and kvec */
-               const struct iovec *iov = i->iov;
+               const struct iovec *iov = iter_iov(i);
                while (1) {
                        size_t n = (--iov)->iov_len;
                        i->nr_segs++;
                        if (unroll <= n) {
-                               i->iov = iov;
+                               i->__iov = iov;
                                i->iov_offset = n - unroll;
                                return;
                        }
@@ -980,7 +1037,7 @@ size_t iov_iter_single_seg_count(const struct iov_iter *i)
 {
        if (i->nr_segs > 1) {
                if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i)))
-                       return min(i->count, i->iov->iov_len - i->iov_offset);
+                       return min(i->count, iter_iov(i)->iov_len - i->iov_offset);
                if (iov_iter_is_bvec(i))
                        return min(i->count, i->bvec->bv_len - i->iov_offset);
        }
@@ -995,6 +1052,7 @@ void iov_iter_kvec(struct iov_iter *i, unsigned int direction,
        WARN_ON(direction & ~(READ | WRITE));
        *i = (struct iov_iter){
                .iter_type = ITER_KVEC,
+               .copy_mc = false,
                .data_source = direction,
                .kvec = kvec,
                .nr_segs = nr_segs,
@@ -1011,6 +1069,7 @@ void iov_iter_bvec(struct iov_iter *i, unsigned int direction,
        WARN_ON(direction & ~(READ | WRITE));
        *i = (struct iov_iter){
                .iter_type = ITER_BVEC,
+               .copy_mc = false,
                .data_source = direction,
                .bvec = bvec,
                .nr_segs = nr_segs,
@@ -1057,6 +1116,7 @@ void iov_iter_xarray(struct iov_iter *i, unsigned int direction,
        BUG_ON(direction & ~1);
        *i = (struct iov_iter) {
                .iter_type = ITER_XARRAY,
+               .copy_mc = false,
                .data_source = direction,
                .xarray = xarray,
                .xarray_start = start,
@@ -1080,6 +1140,7 @@ void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count)
        BUG_ON(direction != READ);
        *i = (struct iov_iter){
                .iter_type = ITER_DISCARD,
+               .copy_mc = false,
                .data_source = false,
                .count = count,
                .iov_offset = 0
@@ -1095,13 +1156,14 @@ static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask,
        unsigned k;
 
        for (k = 0; k < i->nr_segs; k++, skip = 0) {
-               size_t len = i->iov[k].iov_len - skip;
+               const struct iovec *iov = iter_iov(i) + k;
+               size_t len = iov->iov_len - skip;
 
                if (len > size)
                        len = size;
                if (len & len_mask)
                        return false;
-               if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask)
+               if ((unsigned long)(iov->iov_base + skip) & addr_mask)
                        return false;
 
                size -= len;
@@ -1194,9 +1256,10 @@ static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i)
        unsigned k;
 
        for (k = 0; k < i->nr_segs; k++, skip = 0) {
-               size_t len = i->iov[k].iov_len - skip;
+               const struct iovec *iov = iter_iov(i) + k;
+               size_t len = iov->iov_len - skip;
                if (len) {
-                       res |= (unsigned long)i->iov[k].iov_base + skip;
+                       res |= (unsigned long)iov->iov_base + skip;
                        if (len > size)
                                len = size;
                        res |= len;
@@ -1273,14 +1336,15 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
                return ~0U;
 
        for (k = 0; k < i->nr_segs; k++) {
-               if (i->iov[k].iov_len) {
-                       unsigned long base = (unsigned long)i->iov[k].iov_base;
+               const struct iovec *iov = iter_iov(i) + k;
+               if (iov->iov_len) {
+                       unsigned long base = (unsigned long)iov->iov_base;
                        if (v) // if not the first one
                                res |= base | v; // this start | previous end
-                       v = base + i->iov[k].iov_len;
-                       if (size <= i->iov[k].iov_len)
+                       v = base + iov->iov_len;
+                       if (size <= iov->iov_len)
                                break;
-                       size -= i->iov[k].iov_len;
+                       size -= iov->iov_len;
                }
        }
        return res;
@@ -1396,13 +1460,14 @@ static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size)
                return (unsigned long)i->ubuf + i->iov_offset;
 
        for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) {
-               size_t len = i->iov[k].iov_len - skip;
+               const struct iovec *iov = iter_iov(i) + k;
+               size_t len = iov->iov_len - skip;
 
                if (unlikely(!len))
                        continue;
                if (*size > len)
                        *size = len;
-               return (unsigned long)i->iov[k].iov_base + skip;
+               return (unsigned long)iov->iov_base + skip;
        }
        BUG(); // if it had been empty, we wouldn't get called
 }
@@ -1614,7 +1679,7 @@ static int iov_npages(const struct iov_iter *i, int maxpages)
        const struct iovec *p;
        int npages = 0;
 
-       for (p = i->iov; size; skip = 0, p++) {
+       for (p = iter_iov(i); size; skip = 0, p++) {
                unsigned offs = offset_in_page(p->iov_base + skip);
                size_t len = min(p->iov_len - skip, size);
 
@@ -1691,14 +1756,14 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
                                    flags);
        else if (iov_iter_is_kvec(new) || iter_is_iovec(new))
                /* iovec and kvec have identical layout */
-               return new->iov = kmemdup(new->iov,
+               return new->__iov = kmemdup(new->__iov,
                                   new->nr_segs * sizeof(struct iovec),
                                   flags);
        return NULL;
 }
 EXPORT_SYMBOL(dup_iter);
 
-static int copy_compat_iovec_from_user(struct iovec *iov,
+static __noclone int copy_compat_iovec_from_user(struct iovec *iov,
                const struct iovec __user *uvec, unsigned long nr_segs)
 {
        const struct compat_iovec __user *uiov =
@@ -1731,18 +1796,35 @@ uaccess_end:
 }
 
 static int copy_iovec_from_user(struct iovec *iov,
-               const struct iovec __user *uvec, unsigned long nr_segs)
+               const struct iovec __user *uiov, unsigned long nr_segs)
 {
-       unsigned long seg;
+       int ret = -EFAULT;
 
-       if (copy_from_user(iov, uvec, nr_segs * sizeof(*uvec)))
+       if (!user_access_begin(uiov, nr_segs * sizeof(*uiov)))
                return -EFAULT;
-       for (seg = 0; seg < nr_segs; seg++) {
-               if ((ssize_t)iov[seg].iov_len < 0)
-                       return -EINVAL;
-       }
 
-       return 0;
+       do {
+               void __user *buf;
+               ssize_t len;
+
+               unsafe_get_user(len, &uiov->iov_len, uaccess_end);
+               unsafe_get_user(buf, &uiov->iov_base, uaccess_end);
+
+               /* check for size_t not fitting in ssize_t .. */
+               if (unlikely(len < 0)) {
+                       ret = -EINVAL;
+                       goto uaccess_end;
+               }
+               iov->iov_base = buf;
+               iov->iov_len = len;
+
+               uiov++; iov++;
+       } while (--nr_segs);
+
+       ret = 0;
+uaccess_end:
+       user_access_end();
+       return ret;
 }
 
 struct iovec *iovec_from_user(const struct iovec __user *uvec,
@@ -1767,7 +1849,7 @@ struct iovec *iovec_from_user(const struct iovec __user *uvec,
                        return ERR_PTR(-ENOMEM);
        }
 
-       if (compat)
+       if (unlikely(compat))
                ret = copy_compat_iovec_from_user(iov, uvec, nr_segs);
        else
                ret = copy_iovec_from_user(iov, uvec, nr_segs);
@@ -1780,6 +1862,30 @@ struct iovec *iovec_from_user(const struct iovec __user *uvec,
        return iov;
 }
 
+/*
+ * Single segment iovec supplied by the user, import it as ITER_UBUF.
+ */
+static ssize_t __import_iovec_ubuf(int type, const struct iovec __user *uvec,
+                                  struct iovec **iovp, struct iov_iter *i,
+                                  bool compat)
+{
+       struct iovec *iov = *iovp;
+       ssize_t ret;
+
+       if (compat)
+               ret = copy_compat_iovec_from_user(iov, uvec, 1);
+       else
+               ret = copy_iovec_from_user(iov, uvec, 1);
+       if (unlikely(ret))
+               return ret;
+
+       ret = import_ubuf(type, iov->iov_base, iov->iov_len, i);
+       if (unlikely(ret))
+               return ret;
+       *iovp = NULL;
+       return i->count;
+}
+
 ssize_t __import_iovec(int type, const struct iovec __user *uvec,
                 unsigned nr_segs, unsigned fast_segs, struct iovec **iovp,
                 struct iov_iter *i, bool compat)
@@ -1788,6 +1894,9 @@ ssize_t __import_iovec(int type, const struct iovec __user *uvec,
        unsigned long seg;
        struct iovec *iov;
 
+       if (nr_segs == 1)
+               return __import_iovec_ubuf(type, uvec, iovp, i, compat);
+
        iov = iovec_from_user(uvec, nr_segs, fast_segs, *iovp, compat);
        if (IS_ERR(iov)) {
                *iovp = NULL;
@@ -1866,9 +1975,7 @@ int import_single_range(int rw, void __user *buf, size_t len,
        if (unlikely(!access_ok(buf, len)))
                return -EFAULT;
 
-       iov->iov_base = buf;
-       iov->iov_len = len;
-       iov_iter_init(i, rw, iov, 1, len);
+       iov_iter_ubuf(i, rw, buf, len);
        return 0;
 }
 EXPORT_SYMBOL(import_single_range);
@@ -1918,7 +2025,7 @@ void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state)
        if (iov_iter_is_bvec(i))
                i->bvec -= state->nr_segs - i->nr_segs;
        else
-               i->iov -= state->nr_segs - i->nr_segs;
+               i->__iov -= state->nr_segs - i->nr_segs;
        i->nr_segs = state->nr_segs;
 }