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| author | Christian Brauner <christian.brauner@ubuntu.com> | 2019-10-08 15:01:59 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-10 14:39:22 +0200 |
| commit | 51d8a7eca67784b155a07aeab4bfb9f63ebaaf9e (patch) | |
| tree | 8a4c36a4e4c90fe082121c682ff13c101562d28d | |
| parent | misc: fastrpc: prevent memory leak in fastrpc_dma_buf_attach (diff) | |
| download | linux-51d8a7eca67784b155a07aeab4bfb9f63ebaaf9e.tar.xz linux-51d8a7eca67784b155a07aeab4bfb9f63ebaaf9e.zip | |
binder: prevent UAF read in print_binder_transaction_log_entry()
When a binder transaction is initiated on a binder device coming from a
binderfs instance, a pointer to the name of the binder device is stashed
in the binder_transaction_log_entry's context_name member. Later on it
is used to print the name in print_binder_transaction_log_entry(). By
the time print_binder_transaction_log_entry() accesses context_name
binderfs_evict_inode() might have already freed the associated memory
thereby causing a UAF. Do the simple thing and prevent this by copying
the name of the binder device instead of stashing a pointer to it.
Reported-by: Jann Horn <jannh@google.com>
Fixes: 03e2e07e3814 ("binder: Make transaction_log available in binderfs")
Link: https://lore.kernel.org/r/CAG48ez14Q0-F8LqsvcNbyR2o6gPW8SHXsm4u5jmD9MpsteM2Tw@mail.gmail.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Todd Kjos <tkjos@google.com>
Reviewed-by: Hridya Valsaraju <hridya@google.com>
Link: https://lore.kernel.org/r/20191008130159.10161-1-christian.brauner@ubuntu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/android/binder.c | 4 | ||||
| -rw-r--r-- | drivers/android/binder_internal.h | 2 |
2 files changed, 4 insertions, 2 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index c0a491277aca..5b9ac2122e89 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -57,6 +57,7 @@ #include <linux/sched/signal.h> #include <linux/sched/mm.h> #include <linux/seq_file.h> +#include <linux/string.h> #include <linux/uaccess.h> #include <linux/pid_namespace.h> #include <linux/security.h> @@ -66,6 +67,7 @@ #include <linux/task_work.h> #include <uapi/linux/android/binder.h> +#include <uapi/linux/android/binderfs.h> #include <asm/cacheflush.h> @@ -2876,7 +2878,7 @@ static void binder_transaction(struct binder_proc *proc, e->target_handle = tr->target.handle; e->data_size = tr->data_size; e->offsets_size = tr->offsets_size; - e->context_name = proc->context->name; + strscpy(e->context_name, proc->context->name, BINDERFS_MAX_NAME); if (reply) { binder_inner_proc_lock(proc); diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h index bd47f7f72075..ae991097d14d 100644 --- a/drivers/android/binder_internal.h +++ b/drivers/android/binder_internal.h @@ -130,7 +130,7 @@ struct binder_transaction_log_entry { int return_error_line; uint32_t return_error; uint32_t return_error_param; - const char *context_name; + char context_name[BINDERFS_MAX_NAME + 1]; }; struct binder_transaction_log { |