From: Todd Kjos tkjos@android.com
mainline inclusion from mainline-v5.1-rc1 commit ec74136ded792deed80780a2f8baf3521eeb72f9 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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To allow servers to verify client identity, allow a node flag to be set that causes the sender's security context to be delivered with the transaction. The BR_TRANSACTION command is extended in BR_TRANSACTION_SEC_CTX to contain a pointer to the security context string.
Signed-off-by: Todd Kjos tkjos@google.com Reviewed-by: Joel Fernandes (Google) joel@joelfernandes.org 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/binder.c | 106 ++++++++++++++++++++++------ include/uapi/linux/android/binder.h | 19 +++++ 2 files changed, 102 insertions(+), 23 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index f6a8fd678b4b..888af4181941 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -355,6 +355,8 @@ struct binder_error { * (invariant after initialized) * @min_priority: minimum scheduling priority * (invariant after initialized) + * @txn_security_ctx: require sender's security context + * (invariant after initialized) * @async_todo: list of async work items * (protected by @proc->inner_lock) * @@ -391,6 +393,7 @@ struct binder_node { * invariant after initialization */ u8 accept_fds:1; + u8 txn_security_ctx:1; u8 min_priority; }; bool has_async_transaction; @@ -645,6 +648,7 @@ struct binder_transaction { long saved_priority; kuid_t sender_euid; struct list_head fd_fixups; + binder_uintptr_t security_ctx; /** * @lock: protects @from, @to_proc, and @to_thread * @@ -1147,6 +1151,7 @@ static struct binder_node *binder_init_node_ilocked( node->work.type = BINDER_WORK_NODE; node->min_priority = flags & FLAT_BINDER_FLAG_PRIORITY_MASK; node->accept_fds = !!(flags & FLAT_BINDER_FLAG_ACCEPTS_FDS); + node->txn_security_ctx = !!(flags & FLAT_BINDER_FLAG_TXN_SECURITY_CTX); spin_lock_init(&node->lock); INIT_LIST_HEAD(&node->work.entry); INIT_LIST_HEAD(&node->async_todo); @@ -2723,6 +2728,8 @@ static void binder_transaction(struct binder_proc *proc, binder_size_t last_fixup_min_off = 0; struct binder_context *context = proc->context; int t_debug_id = atomic_inc_return(&binder_last_id); + char *secctx = NULL; + u32 secctx_sz = 0;
e = binder_transaction_log_add(&binder_transaction_log); e->debug_id = t_debug_id; @@ -2963,6 +2970,20 @@ static void binder_transaction(struct binder_proc *proc, t->flags = tr->flags; t->priority = task_nice(current);
+ if (target_node && target_node->txn_security_ctx) { + u32 secid; + + security_task_getsecid(proc->tsk, &secid); + ret = security_secid_to_secctx(secid, &secctx, &secctx_sz); + if (ret) { + return_error = BR_FAILED_REPLY; + return_error_param = ret; + return_error_line = __LINE__; + goto err_get_secctx_failed; + } + extra_buffers_size += ALIGN(secctx_sz, sizeof(u64)); + } + trace_binder_transaction(reply, t, target_node);
t->buffer = binder_alloc_new_buf(&target_proc->alloc, tr->data_size, @@ -2979,6 +3000,19 @@ static void binder_transaction(struct binder_proc *proc, t->buffer = NULL; goto err_binder_alloc_buf_failed; } + if (secctx) { + size_t buf_offset = ALIGN(tr->data_size, sizeof(void *)) + + ALIGN(tr->offsets_size, sizeof(void *)) + + ALIGN(extra_buffers_size, sizeof(void *)) - + ALIGN(secctx_sz, sizeof(u64)); + char *kptr = t->buffer->data + buf_offset; + + t->security_ctx = (uintptr_t)kptr + + binder_alloc_get_user_buffer_offset(&target_proc->alloc); + memcpy(kptr, secctx, secctx_sz); + security_release_secctx(secctx, secctx_sz); + secctx = NULL; + } t->buffer->debug_id = t->debug_id; t->buffer->transaction = t; t->buffer->target_node = target_node; @@ -3248,6 +3282,9 @@ static void binder_transaction(struct binder_proc *proc, t->buffer->transaction = NULL; binder_alloc_free_buf(&target_proc->alloc, t->buffer); err_binder_alloc_buf_failed: + if (secctx) + security_release_secctx(secctx, secctx_sz); +err_get_secctx_failed: kfree(tcomplete); binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE); err_alloc_tcomplete_failed: @@ -3981,11 +4018,13 @@ static int binder_thread_read(struct binder_proc *proc,
while (1) { uint32_t cmd; - struct binder_transaction_data tr; + struct binder_transaction_data_secctx tr; + struct binder_transaction_data *trd = &tr.transaction_data; struct binder_work *w = NULL; struct list_head *list = NULL; struct binder_transaction *t = NULL; struct binder_thread *t_from; + size_t trsize = sizeof(*trd);
binder_inner_proc_lock(proc); if (!binder_worklist_empty_ilocked(&thread->todo)) @@ -4180,8 +4219,8 @@ static int binder_thread_read(struct binder_proc *proc, if (t->buffer->target_node) { struct binder_node *target_node = t->buffer->target_node;
- tr.target.ptr = target_node->ptr; - tr.cookie = target_node->cookie; + trd->target.ptr = target_node->ptr; + trd->cookie = target_node->cookie; t->saved_priority = task_nice(current); if (t->priority < target_node->min_priority && !(t->flags & TF_ONE_WAY)) @@ -4191,22 +4230,23 @@ static int binder_thread_read(struct binder_proc *proc, binder_set_nice(target_node->min_priority); cmd = BR_TRANSACTION; } else { - tr.target.ptr = 0; - tr.cookie = 0; + trd->target.ptr = 0; + trd->cookie = 0; cmd = BR_REPLY; } - tr.code = t->code; - tr.flags = t->flags; - tr.sender_euid = from_kuid(current_user_ns(), t->sender_euid); + trd->code = t->code; + trd->flags = t->flags; + trd->sender_euid = from_kuid(current_user_ns(), t->sender_euid);
t_from = binder_get_txn_from(t); if (t_from) { struct task_struct *sender = t_from->proc->tsk;
- tr.sender_pid = task_tgid_nr_ns(sender, - task_active_pid_ns(current)); + trd->sender_pid = + task_tgid_nr_ns(sender, + task_active_pid_ns(current)); } else { - tr.sender_pid = 0; + trd->sender_pid = 0; }
ret = binder_apply_fd_fixups(t); @@ -4237,15 +4277,20 @@ static int binder_thread_read(struct binder_proc *proc, } continue; } - tr.data_size = t->buffer->data_size; - tr.offsets_size = t->buffer->offsets_size; - tr.data.ptr.buffer = (binder_uintptr_t) + trd->data_size = t->buffer->data_size; + trd->offsets_size = t->buffer->offsets_size; + trd->data.ptr.buffer = (binder_uintptr_t) ((uintptr_t)t->buffer->data + binder_alloc_get_user_buffer_offset(&proc->alloc)); - tr.data.ptr.offsets = tr.data.ptr.buffer + + trd->data.ptr.offsets = trd->data.ptr.buffer + ALIGN(t->buffer->data_size, sizeof(void *));
+ tr.secctx = t->security_ctx; + if (t->security_ctx) { + cmd = BR_TRANSACTION_SEC_CTX; + trsize = sizeof(tr); + } if (put_user(cmd, (uint32_t __user *)ptr)) { if (t_from) binder_thread_dec_tmpref(t_from); @@ -4256,7 +4301,7 @@ static int binder_thread_read(struct binder_proc *proc, return -EFAULT; } ptr += sizeof(uint32_t); - if (copy_to_user(ptr, &tr, sizeof(tr))) { + if (copy_to_user(ptr, &tr, trsize)) { if (t_from) binder_thread_dec_tmpref(t_from);
@@ -4265,7 +4310,7 @@ static int binder_thread_read(struct binder_proc *proc,
return -EFAULT; } - ptr += sizeof(tr); + ptr += trsize;
trace_binder_transaction_received(t); binder_stat_br(proc, thread, cmd); @@ -4273,16 +4318,18 @@ static int binder_thread_read(struct binder_proc *proc, "%d:%d %s %d %d:%d, cmd %d size %zd-%zd ptr %016llx-%016llx\n", proc->pid, thread->pid, (cmd == BR_TRANSACTION) ? "BR_TRANSACTION" : - "BR_REPLY", + (cmd == BR_TRANSACTION_SEC_CTX) ? + "BR_TRANSACTION_SEC_CTX" : "BR_REPLY", t->debug_id, t_from ? t_from->proc->pid : 0, t_from ? t_from->pid : 0, cmd, t->buffer->data_size, t->buffer->offsets_size, - (u64)tr.data.ptr.buffer, (u64)tr.data.ptr.offsets); + (u64)trd->data.ptr.buffer, + (u64)trd->data.ptr.offsets);
if (t_from) binder_thread_dec_tmpref(t_from); t->buffer->allow_user_free = 1; - if (cmd == BR_TRANSACTION && !(t->flags & TF_ONE_WAY)) { + if (cmd != BR_REPLY && !(t->flags & TF_ONE_WAY)) { binder_inner_proc_lock(thread->proc); t->to_parent = thread->transaction_stack; t->to_thread = thread; @@ -4631,7 +4678,8 @@ static int binder_ioctl_write_read(struct file *filp, return ret; }
-static int binder_ioctl_set_ctx_mgr(struct file *filp) +static int binder_ioctl_set_ctx_mgr(struct file *filp, + struct flat_binder_object *fbo) { int ret = 0; struct binder_proc *proc = filp->private_data; @@ -4660,7 +4708,7 @@ static int binder_ioctl_set_ctx_mgr(struct file *filp) } else { context->binder_context_mgr_uid = curr_euid; } - new_node = binder_new_node(proc, NULL); + new_node = binder_new_node(proc, fbo); if (!new_node) { ret = -ENOMEM; goto out; @@ -4783,8 +4831,20 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) binder_inner_proc_unlock(proc); break; } + case BINDER_SET_CONTEXT_MGR_EXT: { + struct flat_binder_object fbo; + + if (copy_from_user(&fbo, ubuf, sizeof(fbo))) { + ret = -EINVAL; + goto err; + } + ret = binder_ioctl_set_ctx_mgr(filp, &fbo); + if (ret) + goto err; + break; + } case BINDER_SET_CONTEXT_MGR: - ret = binder_ioctl_set_ctx_mgr(filp); + ret = binder_ioctl_set_ctx_mgr(filp, NULL); if (ret) goto err; break; diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h index b9ba520f7e4b..2832134e5397 100644 --- a/include/uapi/linux/android/binder.h +++ b/include/uapi/linux/android/binder.h @@ -41,6 +41,14 @@ enum { enum { FLAT_BINDER_FLAG_PRIORITY_MASK = 0xff, FLAT_BINDER_FLAG_ACCEPTS_FDS = 0x100, + + /** + * @FLAT_BINDER_FLAG_TXN_SECURITY_CTX: request security contexts + * + * Only when set, causes senders to include their security + * context + */ + FLAT_BINDER_FLAG_TXN_SECURITY_CTX = 0x1000, };
#ifdef BINDER_IPC_32BIT @@ -218,6 +226,7 @@ struct binder_node_info_for_ref { #define BINDER_VERSION _IOWR('b', 9, struct binder_version) #define BINDER_GET_NODE_DEBUG_INFO _IOWR('b', 11, struct binder_node_debug_info) #define BINDER_GET_NODE_INFO_FOR_REF _IOWR('b', 12, struct binder_node_info_for_ref) +#define BINDER_SET_CONTEXT_MGR_EXT _IOW('b', 13, struct flat_binder_object)
/* * NOTE: Two special error codes you should check for when calling @@ -276,6 +285,11 @@ struct binder_transaction_data { } data; };
+struct binder_transaction_data_secctx { + struct binder_transaction_data transaction_data; + binder_uintptr_t secctx; +}; + struct binder_transaction_data_sg { struct binder_transaction_data transaction_data; binder_size_t buffers_size; @@ -311,6 +325,11 @@ enum binder_driver_return_protocol { BR_OK = _IO('r', 1), /* No parameters! */
+ BR_TRANSACTION_SEC_CTX = _IOR('r', 2, + struct binder_transaction_data_secctx), + /* + * binder_transaction_data_secctx: the received command. + */ BR_TRANSACTION = _IOR('r', 2, struct binder_transaction_data), BR_REPLY = _IOR('r', 3, struct binder_transaction_data), /*