From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f73.google.com (mail-oo1-f73.google.com [209.85.161.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 42F5D3B52E8 for ; Fri, 27 Feb 2026 23:39:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772235574; cv=none; b=s4w3XuB95aK7dzx4tiHKtPVkxF+iFCl9tYY5M4Xp0KipkYqQrY4yecJKbktTOJ7a6YqDe3f0zAI4poAfSy7cXgvSMdRGTvjupEP7Dqt395fzE1aCWtyZLdmdpOJW2fj2/OxRtWf18VuPKfmDnhRni/imcSAjtjVddVWtdA1gWUw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772235574; c=relaxed/simple; bh=BjDIIe88AEsckrtwAjj93CmAX57GI3uuDWU+eakcZrQ=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=Mb0fj+ORRBjjOXSVMTPJ7eJwfSNF0H5miZPEzBExqQr8DdqKGS3N3fjVBlwrSAcn/4Pe9K5kivCszWJyhcIIsOt5uDpgN2jg0v9q2FadTCkp3r1kp7unOL8volmCI3BBfU5cSjSSy+qwoOL2kRCdPLJ5//CcO+2aAiGYw9O52VQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--rananta.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=3ANFJIWm; arc=none smtp.client-ip=209.85.161.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--rananta.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="3ANFJIWm" Received: by mail-oo1-f73.google.com with SMTP id 006d021491bc7-679c69b46c6so23826386eaf.0 for ; Fri, 27 Feb 2026 15:39:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772235572; x=1772840372; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=wjWzLo2XlCuyIDdW74QDqar0cCQChKUuTAH2m9cJEjM=; b=3ANFJIWmF57LSdb+z2BoA6wihmUrHg6jgaGmVY3hdwxnDlUzLQjoxjm9EgvU7QvF4Q yz4CViyI+TP3Zu3UuWELyLKirWAkB2PX3RKjCC7QFBJiI2MHTjVwxr99gHjMLnrXOIK3 QZahFWqvfFTOhuARzd4lw2knvInaY61HKARADY7UDScxsCSE2X+aQEzebXxNsi5M7bGa BuWk4UcZTiEBbB2qlYtq4QObYYR3GpOzhLvrpXSXWnw4qD8pk3MVHzZ8tVZH8zJMO/x+ M5aE190ryJ8YjKWr4QRsDsj3G/0FXeztMtyNld6Yxsvw7H5S8H5HA+IMFKf4l0NKt32j XhGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772235572; x=1772840372; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wjWzLo2XlCuyIDdW74QDqar0cCQChKUuTAH2m9cJEjM=; b=a9YVxu4AIrhG5e+tcEEKa/qWPCOL8O99ofqtEk1Ka6pgU7KxD3ZQotc/OHW5Ie0Ezk yvPBuKMPp+Oi20zZJLWTKUhCC/XadhV5OpQi+PfDqDUo+2k+pZjpuhNTPR402ypzP669 LtQev3YqdbecO/6JLMV+nld4UCxKVXzsAMbVk1SA1ibfHBFpeaaJIinSqXtXIWlEfF4O al9xQ/CP6CNfB9xM0R8F4vcFePOGob4wvahWx+sRB8gJHnW/LlqLplkLRKNegzDN4xxu DDsZE0+5W+KzmNbyLx/ykQMcPAh/0UoXO0zEFDGIw7f1sJRzSEjt+Es0q+LD5R5oQaGD kLDg== X-Forwarded-Encrypted: i=1; AJvYcCV/niFwgS/5KpvamB6Uc09BUSMP4hXhK6PvMJAVyrDxJ6KRGshHyEk/LBySwaidTrB83xUu66yfoca3JXM=@vger.kernel.org X-Gm-Message-State: AOJu0Yxvu1xZSCdphKxYrzC+RQEKXF6YONq28Ft2kj5QJfFyxZZzfdxy XFz6iJmyUyey5zfjfCFAVqEvuYJ+XprqQd7DN9tey+b8ngG2GIg/2frjlG6fT7HkaBecWlzDLCp dQw2OJZBKYw== X-Received: from ilsi8.prod.google.com ([2002:a05:6e02:548:b0:4d5:db92:a626]) (user=rananta job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6820:4810:b0:679:a5d2:569b with SMTP id 006d021491bc7-679faf0684fmr2005217eaf.40.1772235572033; Fri, 27 Feb 2026 15:39:32 -0800 (PST) Date: Fri, 27 Feb 2026 23:39:22 +0000 In-Reply-To: <20260227233928.84530-1-rananta@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260227233928.84530-1-rananta@google.com> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260227233928.84530-3-rananta@google.com> Subject: [PATCH v5 2/8] vfio: selftests: Introduce snprintf_assert() From: Raghavendra Rao Ananta To: David Matlack , Alex Williamson Cc: Vipin Sharma , Josh Hilke , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Raghavendra Rao Ananta Content-Type: text/plain; charset="UTF-8" Introduce snprintf_assert() to protect the users of snprintf() to fail if the requested operation was truncated due to buffer limits. VFIO tests and libraries, including a new sysfs library that will be introduced by an upcoming patch, rely quite heavily on snprintf()s to build PCI sysfs paths. Having a protection against this will be helpful to prevent false test failures. Signed-off-by: Raghavendra Rao Ananta Reviewed-by: David Matlack --- .../vfio/lib/include/libvfio/assert.h | 5 +++++ .../selftests/vfio/lib/vfio_pci_device.c | 8 +++---- .../selftests/vfio/vfio_dma_mapping_test.c | 6 +++--- .../selftests/vfio/vfio_pci_device_test.c | 21 ++++++++++--------- 4 files changed, 23 insertions(+), 17 deletions(-) diff --git a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h index f4ebd122d9b6f..77b68c7129a64 100644 --- a/tools/testing/selftests/vfio/lib/include/libvfio/assert.h +++ b/tools/testing/selftests/vfio/lib/include/libvfio/assert.h @@ -51,4 +51,9 @@ VFIO_ASSERT_EQ(__ret, 0, "ioctl(%s, %s, %s) returned %d\n", #_fd, #_op, #_arg, __ret); \ } while (0) +#define snprintf_assert(_s, _size, _fmt, ...) do { \ + int __ret = snprintf(_s, _size, _fmt, ##__VA_ARGS__); \ + VFIO_ASSERT_LT(__ret, _size); \ +} while (0) + #endif /* SELFTESTS_VFIO_LIB_INCLUDE_LIBVFIO_ASSERT_H */ diff --git a/tools/testing/selftests/vfio/lib/vfio_pci_device.c b/tools/testing/selftests/vfio/lib/vfio_pci_device.c index 4e5871f1ebc3b..1538d2b30ae59 100644 --- a/tools/testing/selftests/vfio/lib/vfio_pci_device.c +++ b/tools/testing/selftests/vfio/lib/vfio_pci_device.c @@ -209,7 +209,7 @@ static unsigned int vfio_pci_get_group_from_dev(const char *bdf) unsigned int group; int ret; - snprintf(sysfs_path, PATH_MAX, "%s/%s/iommu_group", PCI_SYSFS_PATH, bdf); + snprintf_assert(sysfs_path, PATH_MAX, "%s/%s/iommu_group", PCI_SYSFS_PATH, bdf); ret = readlink(sysfs_path, dev_iommu_group_path, sizeof(dev_iommu_group_path)); VFIO_ASSERT_NE(ret, -1, "Failed to get the IOMMU group for device: %s\n", bdf); @@ -229,7 +229,7 @@ static void vfio_pci_group_setup(struct vfio_pci_device *device, const char *bdf int group; group = vfio_pci_get_group_from_dev(bdf); - snprintf(group_path, sizeof(group_path), "/dev/vfio/%d", group); + snprintf_assert(group_path, sizeof(group_path), "/dev/vfio/%d", group); device->group_fd = open(group_path, O_RDWR); VFIO_ASSERT_GE(device->group_fd, 0, "open(%s) failed\n", group_path); @@ -300,7 +300,7 @@ const char *vfio_pci_get_cdev_path(const char *bdf) cdev_path = calloc(PATH_MAX, 1); VFIO_ASSERT_NOT_NULL(cdev_path); - snprintf(dir_path, sizeof(dir_path), "/sys/bus/pci/devices/%s/vfio-dev/", bdf); + snprintf_assert(dir_path, sizeof(dir_path), "/sys/bus/pci/devices/%s/vfio-dev/", bdf); dir = opendir(dir_path); VFIO_ASSERT_NOT_NULL(dir, "Failed to open directory %s\n", dir_path); @@ -310,7 +310,7 @@ const char *vfio_pci_get_cdev_path(const char *bdf) if (strncmp("vfio", entry->d_name, 4)) continue; - snprintf(cdev_path, PATH_MAX, "/dev/vfio/devices/%s", entry->d_name); + snprintf_assert(cdev_path, PATH_MAX, "/dev/vfio/devices/%s", entry->d_name); break; } diff --git a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c index abb170bdcef7e..7d0de8c79de13 100644 --- a/tools/testing/selftests/vfio/vfio_dma_mapping_test.c +++ b/tools/testing/selftests/vfio/vfio_dma_mapping_test.c @@ -44,9 +44,9 @@ static int intel_iommu_mapping_get(const char *bdf, u64 iova, FILE *file; char *rest; - snprintf(iommu_mapping_path, sizeof(iommu_mapping_path), - "/sys/kernel/debug/iommu/intel/%s/domain_translation_struct", - bdf); + snprintf_assert(iommu_mapping_path, sizeof(iommu_mapping_path), + "/sys/kernel/debug/iommu/intel/%s/domain_translation_struct", + bdf); printf("Searching for IOVA 0x%lx in %s\n", iova, iommu_mapping_path); diff --git a/tools/testing/selftests/vfio/vfio_pci_device_test.c b/tools/testing/selftests/vfio/vfio_pci_device_test.c index 7c0fe8ce3a61f..93c11fd5e0818 100644 --- a/tools/testing/selftests/vfio/vfio_pci_device_test.c +++ b/tools/testing/selftests/vfio/vfio_pci_device_test.c @@ -39,16 +39,17 @@ FIXTURE_TEARDOWN(vfio_pci_device_test) iommu_cleanup(self->iommu); } -#define read_pci_id_from_sysfs(_file) ({ \ - char __sysfs_path[PATH_MAX]; \ - char __buf[32]; \ - int __fd; \ - \ - snprintf(__sysfs_path, PATH_MAX, "/sys/bus/pci/devices/%s/%s", device_bdf, _file); \ - ASSERT_GT((__fd = open(__sysfs_path, O_RDONLY)), 0); \ - ASSERT_GT(read(__fd, __buf, ARRAY_SIZE(__buf)), 0); \ - ASSERT_EQ(0, close(__fd)); \ - (u16)strtoul(__buf, NULL, 0); \ +#define read_pci_id_from_sysfs(_file) ({ \ + char __sysfs_path[PATH_MAX]; \ + char __buf[32]; \ + int __fd; \ + \ + snprintf_assert(__sysfs_path, PATH_MAX, "/sys/bus/pci/devices/%s/%s", \ + device_bdf, _file); \ + ASSERT_GT((__fd = open(__sysfs_path, O_RDONLY)), 0); \ + ASSERT_GT(read(__fd, __buf, ARRAY_SIZE(__buf)), 0); \ + ASSERT_EQ(0, close(__fd)); \ + (u16)strtoul(__buf, NULL, 0); \ }) TEST_F(vfio_pci_device_test, config_space_read_write) -- 2.53.0.473.g4a7958ca14-goog