From: Todd Kjos tkjos@android.com
mainline inclusion from mainline-v5.1-rc1 commit 8ced0c6231ead26eca8cb416dcb7cc1c2cdd41d8 category: bugfix bugzilla: 188431, https://gitee.com/src-openeuler/kernel/issues/I6DKVG CVE: CVE-2023-20938
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Avoid vm_area when copying to or from binder buffers. Instead, new copy functions are added that copy from kernel space to binder buffer space. These use kmap_atomic() and kunmap_atomic() to create temporary mappings and then memcpy() is used to copy within that page.
Also, kmap_atomic() / kunmap_atomic() use the appropriate cache flushing to support VIVT cache architectures. Allow binder to build if CPU_CACHE_VIVT is defined.
Several uses of the new functions are added here. More to follow in subsequent patches.
Signed-off-by: Todd Kjos tkjos@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Li Huafei lihuafei1@huawei.com Reviewed-by: Zheng Yejian zhengyejian1@huawei.com Reviewed-by: Wang Weiyang wangweiyang2@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- drivers/android/Kconfig | 2 +- drivers/android/binder.c | 119 +++++++++++++++++++++------------ drivers/android/binder_alloc.c | 58 ++++++++++++++++ drivers/android/binder_alloc.h | 12 ++++ 4 files changed, 146 insertions(+), 45 deletions(-)
diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig index 51e8250d113f..432e9ad77070 100644 --- a/drivers/android/Kconfig +++ b/drivers/android/Kconfig @@ -10,7 +10,7 @@ if ANDROID
config ANDROID_BINDER_IPC bool "Android Binder IPC Driver" - depends on MMU && !CPU_CACHE_VIVT + depends on MMU default n ---help--- Binder is used in Android for both communication between processes, diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 8ce21a1019ef..1e5865e0e920 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2254,14 +2254,22 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, off_end = (void *)off_start + buffer->offsets_size; for (offp = off_start; offp < off_end; offp++) { struct binder_object_header *hdr; - size_t object_size = binder_validate_object(buffer, *offp); - + size_t object_size; + binder_size_t object_offset; + binder_size_t buffer_offset = (uintptr_t)offp - + (uintptr_t)buffer->data; + + binder_alloc_copy_from_buffer(&proc->alloc, &object_offset, + buffer, buffer_offset, + sizeof(object_offset)); + object_size = binder_validate_object(buffer, object_offset); if (object_size == 0) { pr_err("transaction release %d bad object at offset %lld, size %zd\n", - debug_id, (u64)*offp, buffer->data_size); + debug_id, (u64)object_offset, buffer->data_size); continue; } - hdr = (struct binder_object_header *)(buffer->data + *offp); + hdr = (struct binder_object_header *) + (buffer->data + object_offset); switch (hdr->type) { case BINDER_TYPE_BINDER: case BINDER_TYPE_WEAK_BINDER: { @@ -2369,8 +2377,20 @@ static void binder_transaction_buffer_release(struct binder_proc *proc, continue; } fd_array = (u32 *)(parent_buffer + (uintptr_t)fda->parent_offset); - for (fd_index = 0; fd_index < fda->num_fds; fd_index++) - binder_deferred_fd_close(fd_array[fd_index]); + for (fd_index = 0; fd_index < fda->num_fds; + fd_index++) { + u32 fd; + binder_size_t offset = + (uintptr_t)&fd_array[fd_index] - + (uintptr_t)buffer->data; + + binder_alloc_copy_from_buffer(&proc->alloc, + &fd, + buffer, + offset, + sizeof(fd)); + binder_deferred_fd_close(fd); + } } break; default: pr_err("transaction release %d bad object type %x\n", @@ -2502,7 +2522,7 @@ static int binder_translate_handle(struct flat_binder_object *fp, return ret; }
-static int binder_translate_fd(u32 *fdp, +static int binder_translate_fd(u32 fd, binder_size_t fd_offset, struct binder_transaction *t, struct binder_thread *thread, struct binder_transaction *in_reply_to) @@ -2513,7 +2533,6 @@ static int binder_translate_fd(u32 *fdp, struct file *file; int ret = 0; bool target_allows_fd; - int fd = *fdp;
if (in_reply_to) target_allows_fd = !!(in_reply_to->flags & TF_ACCEPT_FDS); @@ -2552,7 +2571,7 @@ static int binder_translate_fd(u32 *fdp, goto err_alloc; } fixup->file = file; - fixup->offset = (uintptr_t)fdp - (uintptr_t)t->buffer->data; + fixup->offset = fd_offset; trace_binder_transaction_fd_send(t, fd, fixup->offset); list_add_tail(&fixup->fixup_entry, &t->fd_fixups);
@@ -2604,8 +2623,17 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda, return -EINVAL; } for (fdi = 0; fdi < fda->num_fds; fdi++) { - int ret = binder_translate_fd(&fd_array[fdi], t, thread, - in_reply_to); + u32 fd; + int ret; + binder_size_t offset = + (uintptr_t)&fd_array[fdi] - + (uintptr_t)t->buffer->data; + + binder_alloc_copy_from_buffer(&target_proc->alloc, + &fd, t->buffer, + offset, sizeof(fd)); + ret = binder_translate_fd(fd, offset, t, thread, + in_reply_to); if (ret < 0) return ret; } @@ -3070,7 +3098,9 @@ static void binder_transaction(struct binder_proc *proc,
t->security_ctx = (uintptr_t)kptr + binder_alloc_get_user_buffer_offset(&target_proc->alloc); - memcpy(kptr, secctx, secctx_sz); + binder_alloc_copy_to_buffer(&target_proc->alloc, + t->buffer, buf_offset, + secctx, secctx_sz); security_release_secctx(secctx, secctx_sz); secctx = NULL; } @@ -3132,11 +3162,21 @@ static void binder_transaction(struct binder_proc *proc, off_min = 0; for (; offp < off_end; offp++) { struct binder_object_header *hdr; - size_t object_size = binder_validate_object(t->buffer, *offp); - - if (object_size == 0 || *offp < off_min) { + size_t object_size; + binder_size_t object_offset; + binder_size_t buffer_offset = + (uintptr_t)offp - (uintptr_t)t->buffer->data; + + binder_alloc_copy_from_buffer(&target_proc->alloc, + &object_offset, + t->buffer, + buffer_offset, + sizeof(object_offset)); + object_size = binder_validate_object(t->buffer, object_offset); + if (object_size == 0 || object_offset < off_min) { binder_user_error("%d:%d got transaction with invalid offset (%lld, min %lld max %lld) or object.\n", - proc->pid, thread->pid, (u64)*offp, + proc->pid, thread->pid, + (u64)object_offset, (u64)off_min, (u64)t->buffer->data_size); return_error = BR_FAILED_REPLY; @@ -3145,8 +3185,9 @@ static void binder_transaction(struct binder_proc *proc, goto err_bad_offset; }
- hdr = (struct binder_object_header *)(t->buffer->data + *offp); - off_min = *offp + object_size; + hdr = (struct binder_object_header *) + (t->buffer->data + object_offset); + off_min = object_offset + object_size; switch (hdr->type) { case BINDER_TYPE_BINDER: case BINDER_TYPE_WEAK_BINDER: { @@ -3177,8 +3218,10 @@ static void binder_transaction(struct binder_proc *proc,
case BINDER_TYPE_FD: { struct binder_fd_object *fp = to_binder_fd_object(hdr); - int ret = binder_translate_fd(&fp->fd, t, thread, - in_reply_to); + binder_size_t fd_offset = object_offset + + (uintptr_t)&fp->fd - (uintptr_t)fp; + int ret = binder_translate_fd(fp->fd, fd_offset, t, + thread, in_reply_to);
if (ret < 0) { return_error = BR_FAILED_REPLY; @@ -3973,6 +4016,7 @@ static int binder_wait_for_work(struct binder_thread *thread,
/** * binder_apply_fd_fixups() - finish fd translation + * @proc: binder_proc associated @t->buffer * @t: binder transaction with list of fd fixups * * Now that we are in the context of the transaction target @@ -3984,14 +4028,14 @@ static int binder_wait_for_work(struct binder_thread *thread, * fput'ing files that have not been processed and ksys_close'ing * any fds that have already been allocated. */ -static int binder_apply_fd_fixups(struct binder_transaction *t) +static int binder_apply_fd_fixups(struct binder_proc *proc, + struct binder_transaction *t) { struct binder_txn_fd_fixup *fixup, *tmp; int ret = 0;
list_for_each_entry(fixup, &t->fd_fixups, fixup_entry) { int fd = get_unused_fd_flags(O_CLOEXEC); - u32 *fdp;
if (fd < 0) { binder_debug(BINDER_DEBUG_TRANSACTION, @@ -4006,33 +4050,20 @@ static int binder_apply_fd_fixups(struct binder_transaction *t) trace_binder_transaction_fd_recv(t, fd, fixup->offset); fd_install(fd, fixup->file); fixup->file = NULL; - fdp = (u32 *)(t->buffer->data + fixup->offset); - /* - * This store can cause problems for CPUs with a - * VIVT cache (eg ARMv5) since the cache cannot - * detect virtual aliases to the same physical cacheline. - * To support VIVT, this address and the user-space VA - * would both need to be flushed. Since this kernel - * VA is not constructed via page_to_virt(), we can't - * use flush_dcache_page() on it, so we'd have to use - * an internal function. If devices with VIVT ever - * need to run Android, we'll either need to go back - * to patching the translated fd from the sender side - * (using the non-standard kernel functions), or rework - * how the kernel uses the buffer to use page_to_virt() - * addresses instead of allocating in our own vm area. - * - * For now, we disable compilation if CONFIG_CPU_CACHE_VIVT. - */ - *fdp = fd; + binder_alloc_copy_to_buffer(&proc->alloc, t->buffer, + fixup->offset, &fd, + sizeof(u32)); } list_for_each_entry_safe(fixup, tmp, &t->fd_fixups, fixup_entry) { if (fixup->file) { fput(fixup->file); } else if (ret) { - u32 *fdp = (u32 *)(t->buffer->data + fixup->offset); + u32 fd;
- binder_deferred_fd_close(*fdp); + binder_alloc_copy_from_buffer(&proc->alloc, &fd, + t->buffer, fixup->offset, + sizeof(fd)); + binder_deferred_fd_close(fd); } list_del(&fixup->fixup_entry); kfree(fixup); @@ -4325,7 +4356,7 @@ static int binder_thread_read(struct binder_proc *proc, trd->sender_pid = 0; }
- ret = binder_apply_fd_fixups(t); + ret = binder_apply_fd_fixups(proc, t); if (ret) { struct binder_buffer *buffer = t->buffer; bool oneway = !!(t->flags & TF_ONE_WAY); diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 342fbe124628..f3054e30e85b 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -1171,3 +1171,61 @@ binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc, } return 0; } + +static void binder_alloc_do_buffer_copy(struct binder_alloc *alloc, + bool to_buffer, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + void *ptr, + size_t bytes) +{ + /* All copies must be 32-bit aligned and 32-bit size */ + BUG_ON(!check_buffer(alloc, buffer, buffer_offset, bytes)); + + while (bytes) { + unsigned long size; + struct page *page; + pgoff_t pgoff; + void *tmpptr; + void *base_ptr; + + page = binder_alloc_get_page(alloc, buffer, + buffer_offset, &pgoff); + size = min_t(size_t, bytes, PAGE_SIZE - pgoff); + base_ptr = kmap_atomic(page); + tmpptr = base_ptr + pgoff; + if (to_buffer) + memcpy(tmpptr, ptr, size); + else + memcpy(ptr, tmpptr, size); + /* + * kunmap_atomic() takes care of flushing the cache + * if this device has VIVT cache arch + */ + kunmap_atomic(base_ptr); + bytes -= size; + pgoff = 0; + ptr = ptr + size; + buffer_offset += size; + } +} + +void binder_alloc_copy_to_buffer(struct binder_alloc *alloc, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + void *src, + size_t bytes) +{ + binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset, + src, bytes); +} + +void binder_alloc_copy_from_buffer(struct binder_alloc *alloc, + void *dest, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + size_t bytes) +{ + binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset, + dest, bytes); +} diff --git a/drivers/android/binder_alloc.h b/drivers/android/binder_alloc.h index 995155f31dbd..9d682b9d6c24 100644 --- a/drivers/android/binder_alloc.h +++ b/drivers/android/binder_alloc.h @@ -191,5 +191,17 @@ binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc, const void __user *from, size_t bytes);
+void binder_alloc_copy_to_buffer(struct binder_alloc *alloc, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + void *src, + size_t bytes); + +void binder_alloc_copy_from_buffer(struct binder_alloc *alloc, + void *dest, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + size_t bytes); + #endif /* _LINUX_BINDER_ALLOC_H */