diff options
| author |   Hyunwoo Kim <imv4bel@gmail.com> | 2022-09-07 09:07:14 -0700 |
|---|---|---|
| committer |   Ard Biesheuvel <ardb@kernel.org> | 2022-09-07 18:23:56 +0200 |
| commit | 9cb636b5f6a8cc6d1b50809ec8f8d33ae0c84c95 (patch) | |
| tree | bd9589d71ff723e58ae7ef421691f7728e7e8e0c /drivers/firmware | |
| parent | efi/x86: libstub: remove unused variable (diff) | |
| download | linux-dev-9cb636b5f6a8cc6d1b50809ec8f8d33ae0c84c95.tar.xz linux-dev-9cb636b5f6a8cc6d1b50809ec8f8d33ae0c84c95.zip | |
efi: capsule-loader: Fix use-after-free in efi_capsule_write
A race condition may occur if the user calls close() on another thread
during a write() operation on the device node of the efi capsule.
This is a race condition that occurs between the efi_capsule_write() and
efi_capsule_flush() functions of efi_capsule_fops, which ultimately
results in UAF.
So, the page freeing process is modified to be done in
efi_capsule_release() instead of efi_capsule_flush().
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Link: https://lore.kernel.org/all/20220907102920.GA88602@ubuntu/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efi/capsule-loader.c | 31 |
1 files changed, 7 insertions, 24 deletions
diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c index 4dde8edd53b6..3e8d4b51a814 100644 --- a/drivers/firmware/efi/capsule-loader.c +++ b/drivers/firmware/efi/capsule-loader.c @@ -243,29 +243,6 @@ failed: } /** - * efi_capsule_flush - called by file close or file flush - * @file: file pointer - * @id: not used - * - * If a capsule is being partially uploaded then calling this function - * will be treated as upload termination and will free those completed - * buffer pages and -ECANCELED will be returned. - **/ -static int efi_capsule_flush(struct file *file, fl_owner_t id) -{ - int ret = 0; - struct capsule_info *cap_info = file->private_data; - - if (cap_info->index > 0) { - pr_err("capsule upload not complete\n"); - efi_free_all_buff_pages(cap_info); - ret = -ECANCELED; - } - - return ret; -} - -/** * efi_capsule_release - called by file close * @inode: not used * @file: file pointer @@ -277,6 +254,13 @@ static int efi_capsule_release(struct inode *inode, struct file *file) { struct capsule_info *cap_info = file->private_data; + if (cap_info->index > 0 && + (cap_info->header.headersize == 0 || + cap_info->count < cap_info->total_size)) { + pr_err("capsule upload not complete\n"); + efi_free_all_buff_pages(cap_info); + } + kfree(cap_info->pages); kfree(cap_info->phys); kfree(file->private_data); @@ -324,7 +308,6 @@ static const struct file_operations efi_capsule_fops = { .owner = THIS_MODULE, .open = efi_capsule_open, .write = efi_capsule_write, - .flush = efi_capsule_flush, .release = efi_capsule_release, .llseek = no_llseek, }; |