[PATCH] kunit: tool: Don't download risc-v opensbi firmware with wget

[David Gow <davidgow@google.com>]

When running a RISC-V test kernel under QEMU, we need an OpenSBI BIOS
file. In the original QEMU support patchset, kunit_tool would optionally
download this file from GitHub if it didn't exist, using wget.

These days, it can usually be found in the distro's qemu-system-riscv
package, and is located in /usr/share/qemu on all the distros I tried
(Debian, Arch, OpenSUSE). Use this file, and thereby don't do any
downloading in kunit_tool.

In addition, we used to shell out to whatever 'wget' was in the path,
which could have potentially been used to trick the developer into
running another binary. By not using wget at all, we nicely sidestep
this issue.

Cc: Xu Panda <xu.panda@zte.com.cn>
Fixes: 87c9c1631788 ("kunit: tool: add support for QEMU")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: David Gow <davidgow@google.com>
---

This is a replacement for "kunit: tool: use absolute path for wget":
https://lore.kernel.org/linux-kselftest/20220922083610.235936-1-xu.panda@zte.com.cn/

Instead of just changing the path to wget, it removes the download
option completely and grabs the opensbi-riscv64-generic-fw_dynamic.bin
from the /usr/share/qemu directory, where the distro package manager
should have put it.

I _think_ this should be okay to treat as a fix: we were always grabbing
this from the QEMU GitHub repository, so it should be widely available.
And if you want to treat the wget use as a security issue, getting rid
of it everywhere would be nice.

Thoughts?

-- David

---
 tools/testing/kunit/qemu_configs/riscv.py | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/tools/testing/kunit/qemu_configs/riscv.py b/tools/testing/kunit/qemu_configs/riscv.py
index 6207be146d26..12a1d525978a 100644
--- a/tools/testing/kunit/qemu_configs/riscv.py
+++ b/tools/testing/kunit/qemu_configs/riscv.py
@@ -3,17 +3,13 @@ import os
 import os.path
 import sys
 
-GITHUB_OPENSBI_URL = 'https://github.com/qemu/qemu/raw/master/pc-bios/opensbi-riscv64-generic-fw_dynamic.bin'
-OPENSBI_FILE = os.path.basename(GITHUB_OPENSBI_URL)
+OPENSBI_FILE = 'opensbi-riscv64-generic-fw_dynamic.bin'
+OPENSBI_PATH = '/usr/share/qemu/' + OPENSBI_FILE
 
-if not os.path.isfile(OPENSBI_FILE):
-	print('\n\nOpenSBI file is not in the current working directory.\n'
-	      'Would you like me to download it for you from:\n' + GITHUB_OPENSBI_URL + ' ?\n')
-	response = input('yes/[no]: ')
-	if response.strip() == 'yes':
-		os.system('wget ' + GITHUB_OPENSBI_URL)
-	else:
-		sys.exit()
+if not os.path.isfile(OPENSBI_PATH):
+	print('\n\nOpenSBI bios was not found in "' + OPENSBI_PATH + '".\n'
+	      'Please ensure that qemu-system-riscv is installed, or edit the path in "qemu_configs/riscv.py"\n')
+	sys.exit()
 
 QEMU_ARCH = QemuArchParams(linux_arch='riscv',
 			   kconfig='''
@@ -29,4 +25,4 @@ CONFIG_SERIAL_EARLYCON_RISCV_SBI=y''',
 			   extra_qemu_params=[
 					   '-machine', 'virt',
 					   '-cpu', 'rv64',
-					   '-bios', 'opensbi-riscv64-generic-fw_dynamic.bin'])
+					   '-bios', OPENSBI_PATH])
-- 
2.37.3.998.g577e59143f-goog