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Message-ID: <20200623174438.GL4151@kadam>
Date: Tue, 23 Jun 2020 20:44:38 +0300
From: Dan Carpenter <dan.carpenter@...cle.com>
To: kbuild@...ts.01.org, Kent Gibson <warthog618@...il.com>,
linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
bgolaszewski@...libre.com, linus.walleij@...aro.org
Cc: lkp@...el.com, kbuild-all@...ts.01.org,
Kent Gibson <warthog618@...il.com>
Subject: Re: [PATCH 16/22] gpiolib: cdev: add V2 uAPI implementation to
parity with V1
[ The copy_to_user() overflow code is weird. Why do we need to do a
atomic_read()? That suggests that there is a potential time of check
time of use bug where we do:
if (atomic_read(&gcdev->watch_abi_version) == 2) // <<-- time of check
event_size = sizeof(struct gpioline_info_changed_v2);
...
if (atomic_read(&gcdev->watch_abi_version) == 2) { // <<-- time of use
copy_to_user(blah, blah, event_size);
If the value for "gcdev->watch_abi_version" changes between the time
of check and the time of use then it can read beyond the end of the
buffer.
-- dan ]
Hi Kent,
Thank you for the patch! Perhaps something to improve:
url: https://github.com/0day-ci/linux/commits/Kent-Gibson/gpio-cdev-add-uAPI-V2/20200623-120634
base: https://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git for-next
config: openrisc-randconfig-m031-20200623 (attached as .config)
compiler: or1k-linux-gcc (GCC) 9.3.0
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...cle.com>
smatch warnings:
drivers/gpio/gpiolib-cdev.c:891 line_free() error: dereferencing freed memory 'line'
drivers/gpio/gpiolib-cdev.c:949 line_create() warn: possible memory leak of 'line'
drivers/gpio/gpiolib-cdev.c:1860 lineinfo_watch_read() error: copy_to_user() '&event_v1' too small (104 vs 168)
# https://github.com/0day-ci/linux/commit/f3b3ae8752adc5ac33dcf83d49b0b02f2d7ef43b
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout f3b3ae8752adc5ac33dcf83d49b0b02f2d7ef43b
vim +/line +891 drivers/gpio/gpiolib-cdev.c
f3b3ae8752adc5 Kent Gibson 2020-06-23 877 static void line_free(struct line *line)
f3b3ae8752adc5 Kent Gibson 2020-06-23 878 {
f3b3ae8752adc5 Kent Gibson 2020-06-23 879 int i;
f3b3ae8752adc5 Kent Gibson 2020-06-23 880
f3b3ae8752adc5 Kent Gibson 2020-06-23 881 for (i = 0; i < line->num_descs; i++) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 882 if (line->edets)
f3b3ae8752adc5 Kent Gibson 2020-06-23 883 edge_detector_stop(&line->edets[i]);
f3b3ae8752adc5 Kent Gibson 2020-06-23 884 if (line->descs[i])
f3b3ae8752adc5 Kent Gibson 2020-06-23 885 gpiod_free(line->descs[i]);
f3b3ae8752adc5 Kent Gibson 2020-06-23 886 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 887 kfifo_free(&line->events);
f3b3ae8752adc5 Kent Gibson 2020-06-23 888 kfree(line->label);
f3b3ae8752adc5 Kent Gibson 2020-06-23 889 kfree(line->edets);
f3b3ae8752adc5 Kent Gibson 2020-06-23 890 kfree(line);
f3b3ae8752adc5 Kent Gibson 2020-06-23 @891 put_device(&line->gdev->dev);
f3b3ae8752adc5 Kent Gibson 2020-06-23 892 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 893
f3b3ae8752adc5 Kent Gibson 2020-06-23 894 static int line_release(struct inode *inode, struct file *file)
f3b3ae8752adc5 Kent Gibson 2020-06-23 895 {
f3b3ae8752adc5 Kent Gibson 2020-06-23 896 struct line *line = file->private_data;
f3b3ae8752adc5 Kent Gibson 2020-06-23 897
f3b3ae8752adc5 Kent Gibson 2020-06-23 898 line_free(line);
f3b3ae8752adc5 Kent Gibson 2020-06-23 899 return 0;
f3b3ae8752adc5 Kent Gibson 2020-06-23 900 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 901
f3b3ae8752adc5 Kent Gibson 2020-06-23 902 static const struct file_operations line_fileops = {
f3b3ae8752adc5 Kent Gibson 2020-06-23 903 .release = line_release,
f3b3ae8752adc5 Kent Gibson 2020-06-23 904 .read = line_read,
f3b3ae8752adc5 Kent Gibson 2020-06-23 905 .poll = line_poll,
f3b3ae8752adc5 Kent Gibson 2020-06-23 906 .owner = THIS_MODULE,
f3b3ae8752adc5 Kent Gibson 2020-06-23 907 .llseek = noop_llseek,
f3b3ae8752adc5 Kent Gibson 2020-06-23 908 .unlocked_ioctl = line_ioctl,
f3b3ae8752adc5 Kent Gibson 2020-06-23 909 #ifdef CONFIG_COMPAT
f3b3ae8752adc5 Kent Gibson 2020-06-23 910 .compat_ioctl = line_ioctl_compat,
f3b3ae8752adc5 Kent Gibson 2020-06-23 911 #endif
f3b3ae8752adc5 Kent Gibson 2020-06-23 912 };
f3b3ae8752adc5 Kent Gibson 2020-06-23 913
f3b3ae8752adc5 Kent Gibson 2020-06-23 914 static int line_create(struct gpio_device *gdev, void __user *ip)
f3b3ae8752adc5 Kent Gibson 2020-06-23 915 {
f3b3ae8752adc5 Kent Gibson 2020-06-23 916 struct gpioline_request linereq;
f3b3ae8752adc5 Kent Gibson 2020-06-23 917 struct line *line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 918 struct file *file;
f3b3ae8752adc5 Kent Gibson 2020-06-23 919 int fd, i, ret, size;
f3b3ae8752adc5 Kent Gibson 2020-06-23 920 struct gpioline_config *lc;
f3b3ae8752adc5 Kent Gibson 2020-06-23 921 unsigned long *vals;
f3b3ae8752adc5 Kent Gibson 2020-06-23 922
f3b3ae8752adc5 Kent Gibson 2020-06-23 923 if (copy_from_user(&linereq, ip, sizeof(linereq)))
f3b3ae8752adc5 Kent Gibson 2020-06-23 924 return -EFAULT;
f3b3ae8752adc5 Kent Gibson 2020-06-23 925 if ((linereq.num_lines == 0) || (linereq.num_lines > GPIOLINES_MAX))
f3b3ae8752adc5 Kent Gibson 2020-06-23 926 return -EINVAL;
f3b3ae8752adc5 Kent Gibson 2020-06-23 927
f3b3ae8752adc5 Kent Gibson 2020-06-23 928 if (padding_not_zeroed(linereq.padding, GPIOLINE_REQUEST_PAD_SIZE))
f3b3ae8752adc5 Kent Gibson 2020-06-23 929 return -EINVAL;
f3b3ae8752adc5 Kent Gibson 2020-06-23 930
f3b3ae8752adc5 Kent Gibson 2020-06-23 931 lc = &linereq.config;
f3b3ae8752adc5 Kent Gibson 2020-06-23 932 ret = gpioline_config_validate(lc);
f3b3ae8752adc5 Kent Gibson 2020-06-23 933 if (ret)
f3b3ae8752adc5 Kent Gibson 2020-06-23 934 return ret;
f3b3ae8752adc5 Kent Gibson 2020-06-23 935
f3b3ae8752adc5 Kent Gibson 2020-06-23 936 /* event_buffer_size only valid with edge_detection */
f3b3ae8752adc5 Kent Gibson 2020-06-23 937 if ((linereq.event_buffer_size) &&
f3b3ae8752adc5 Kent Gibson 2020-06-23 938 !(linereq.config.flags & GPIOLINE_FLAG_V2_EDGE_DETECTION))
f3b3ae8752adc5 Kent Gibson 2020-06-23 939 return -EINVAL;
f3b3ae8752adc5 Kent Gibson 2020-06-23 940
f3b3ae8752adc5 Kent Gibson 2020-06-23 941 line = kzalloc(struct_size(line, descs, linereq.num_lines),
f3b3ae8752adc5 Kent Gibson 2020-06-23 942 GFP_KERNEL);
f3b3ae8752adc5 Kent Gibson 2020-06-23 943 if (!line)
f3b3ae8752adc5 Kent Gibson 2020-06-23 944 return -ENOMEM;
f3b3ae8752adc5 Kent Gibson 2020-06-23 945
f3b3ae8752adc5 Kent Gibson 2020-06-23 946 line->edets = kcalloc(linereq.num_lines, sizeof(*line->edets),
f3b3ae8752adc5 Kent Gibson 2020-06-23 947 GFP_KERNEL);
f3b3ae8752adc5 Kent Gibson 2020-06-23 948 if (!line->edets)
f3b3ae8752adc5 Kent Gibson 2020-06-23 @949 return -ENOMEM;
^^^^^^^^^^^^^^^
kfree(line) before returning.
f3b3ae8752adc5 Kent Gibson 2020-06-23 950
f3b3ae8752adc5 Kent Gibson 2020-06-23 951 for (i = 0; i < linereq.num_lines; i++)
f3b3ae8752adc5 Kent Gibson 2020-06-23 952 line->edets[i].line = line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 953
f3b3ae8752adc5 Kent Gibson 2020-06-23 954 line->gdev = gdev;
f3b3ae8752adc5 Kent Gibson 2020-06-23 955 get_device(&gdev->dev);
f3b3ae8752adc5 Kent Gibson 2020-06-23 956
f3b3ae8752adc5 Kent Gibson 2020-06-23 957 /* Make sure this is terminated */
f3b3ae8752adc5 Kent Gibson 2020-06-23 958 linereq.consumer[sizeof(linereq.consumer)-1] = '\0';
f3b3ae8752adc5 Kent Gibson 2020-06-23 959 if (strlen(linereq.consumer)) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 960 line->label = kstrdup(linereq.consumer, GFP_KERNEL);
f3b3ae8752adc5 Kent Gibson 2020-06-23 961 if (!line->label) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 962 ret = -ENOMEM;
f3b3ae8752adc5 Kent Gibson 2020-06-23 963 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 964 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 965 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 966
f3b3ae8752adc5 Kent Gibson 2020-06-23 967 mutex_init(&line->config_mutex);
f3b3ae8752adc5 Kent Gibson 2020-06-23 968 init_waitqueue_head(&line->wait);
f3b3ae8752adc5 Kent Gibson 2020-06-23 969 if (lc->edge_detection) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 970 size = linereq.event_buffer_size;
f3b3ae8752adc5 Kent Gibson 2020-06-23 971
f3b3ae8752adc5 Kent Gibson 2020-06-23 972 if (size > GPIOLINES_MAX*16)
f3b3ae8752adc5 Kent Gibson 2020-06-23 973 size = GPIOLINES_MAX*16;
f3b3ae8752adc5 Kent Gibson 2020-06-23 974 else if (size == 0)
f3b3ae8752adc5 Kent Gibson 2020-06-23 975 size = linereq.num_lines*16;
f3b3ae8752adc5 Kent Gibson 2020-06-23 976
f3b3ae8752adc5 Kent Gibson 2020-06-23 977 ret = kfifo_alloc(&line->events, size, GFP_KERNEL);
f3b3ae8752adc5 Kent Gibson 2020-06-23 978 if (ret)
f3b3ae8752adc5 Kent Gibson 2020-06-23 979 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 980
f3b3ae8752adc5 Kent Gibson 2020-06-23 981 line->edge_detection = lc->edge_detection;
f3b3ae8752adc5 Kent Gibson 2020-06-23 982 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 983
f3b3ae8752adc5 Kent Gibson 2020-06-23 984 atomic_set(&line->seqno, 0);
f3b3ae8752adc5 Kent Gibson 2020-06-23 985 line->num_descs = linereq.num_lines;
f3b3ae8752adc5 Kent Gibson 2020-06-23 986 vals = (unsigned long *)lc->values.bitmap;
f3b3ae8752adc5 Kent Gibson 2020-06-23 987
f3b3ae8752adc5 Kent Gibson 2020-06-23 988 /* Request each GPIO */
f3b3ae8752adc5 Kent Gibson 2020-06-23 989 for (i = 0; i < linereq.num_lines; i++) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 990 u32 offset = linereq.offsets[i];
f3b3ae8752adc5 Kent Gibson 2020-06-23 991 struct gpio_desc *desc = gpiochip_get_desc(gdev->chip, offset);
f3b3ae8752adc5 Kent Gibson 2020-06-23 992
f3b3ae8752adc5 Kent Gibson 2020-06-23 993 if (IS_ERR(desc)) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 994 ret = PTR_ERR(desc);
f3b3ae8752adc5 Kent Gibson 2020-06-23 995 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 996 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 997
f3b3ae8752adc5 Kent Gibson 2020-06-23 998 ret = gpiod_request(desc, line->label);
f3b3ae8752adc5 Kent Gibson 2020-06-23 999 if (ret)
f3b3ae8752adc5 Kent Gibson 2020-06-23 1000 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1001
f3b3ae8752adc5 Kent Gibson 2020-06-23 1002 line->descs[i] = desc;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1003 gpioline_config_to_desc_flags(lc, &desc->flags);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1004
f3b3ae8752adc5 Kent Gibson 2020-06-23 1005 ret = gpiod_set_transitory(desc, false);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1006 if (ret < 0)
f3b3ae8752adc5 Kent Gibson 2020-06-23 1007 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1008
f3b3ae8752adc5 Kent Gibson 2020-06-23 1009 /*
f3b3ae8752adc5 Kent Gibson 2020-06-23 1010 * Lines have to be requested explicitly for input
f3b3ae8752adc5 Kent Gibson 2020-06-23 1011 * or output, else the line will be treated "as is".
f3b3ae8752adc5 Kent Gibson 2020-06-23 1012 */
f3b3ae8752adc5 Kent Gibson 2020-06-23 1013 if (lc->flags & GPIOLINE_FLAG_V2_DIRECTION) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 1014 if (lc->direction == GPIOLINE_DIRECTION_OUTPUT) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 1015 int val = test_bit(i, vals);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1016
f3b3ae8752adc5 Kent Gibson 2020-06-23 1017 ret = gpiod_direction_output(desc, val);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1018 if (ret)
f3b3ae8752adc5 Kent Gibson 2020-06-23 1019 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1020 } else {
f3b3ae8752adc5 Kent Gibson 2020-06-23 1021 ret = gpiod_direction_input(desc);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1022 if (ret)
f3b3ae8752adc5 Kent Gibson 2020-06-23 1023 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1024 ret = edge_detector_setup(&line->edets[i], lc);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1025 if (ret)
f3b3ae8752adc5 Kent Gibson 2020-06-23 1026 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1027 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 1028 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 1029
f3b3ae8752adc5 Kent Gibson 2020-06-23 1030 atomic_notifier_call_chain(&desc->gdev->notifier,
f3b3ae8752adc5 Kent Gibson 2020-06-23 1031 GPIOLINE_CHANGED_REQUESTED, desc);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1032
f3b3ae8752adc5 Kent Gibson 2020-06-23 1033 dev_dbg(&gdev->dev, "registered chardev handle for line %d\n",
f3b3ae8752adc5 Kent Gibson 2020-06-23 1034 offset);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1035 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 1036
f3b3ae8752adc5 Kent Gibson 2020-06-23 1037 fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1038 if (fd < 0) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 1039 ret = fd;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1040 goto out_free_line;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1041 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 1042
f3b3ae8752adc5 Kent Gibson 2020-06-23 1043 file = anon_inode_getfile("gpio-line",
f3b3ae8752adc5 Kent Gibson 2020-06-23 1044 &line_fileops,
f3b3ae8752adc5 Kent Gibson 2020-06-23 1045 line,
f3b3ae8752adc5 Kent Gibson 2020-06-23 1046 O_RDONLY | O_CLOEXEC);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1047 if (IS_ERR(file)) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 1048 ret = PTR_ERR(file);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1049 goto out_put_unused_fd;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1050 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 1051
f3b3ae8752adc5 Kent Gibson 2020-06-23 1052 linereq.fd = fd;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1053 if (copy_to_user(ip, &linereq, sizeof(linereq))) {
f3b3ae8752adc5 Kent Gibson 2020-06-23 1054 /*
f3b3ae8752adc5 Kent Gibson 2020-06-23 1055 * fput() will trigger the release() callback, so do not go onto
f3b3ae8752adc5 Kent Gibson 2020-06-23 1056 * the regular error cleanup path here.
f3b3ae8752adc5 Kent Gibson 2020-06-23 1057 */
f3b3ae8752adc5 Kent Gibson 2020-06-23 1058 fput(file);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1059 put_unused_fd(fd);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1060 return -EFAULT;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1061 }
f3b3ae8752adc5 Kent Gibson 2020-06-23 1062
f3b3ae8752adc5 Kent Gibson 2020-06-23 1063 fd_install(fd, file);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1064
f3b3ae8752adc5 Kent Gibson 2020-06-23 1065 dev_dbg(&gdev->dev, "registered chardev handle for %d lines\n",
f3b3ae8752adc5 Kent Gibson 2020-06-23 1066 line->num_descs);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1067
f3b3ae8752adc5 Kent Gibson 2020-06-23 1068 return 0;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1069
f3b3ae8752adc5 Kent Gibson 2020-06-23 1070 out_put_unused_fd:
f3b3ae8752adc5 Kent Gibson 2020-06-23 1071 put_unused_fd(fd);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1072 out_free_line:
f3b3ae8752adc5 Kent Gibson 2020-06-23 1073 line_free(line);
f3b3ae8752adc5 Kent Gibson 2020-06-23 1074 return ret;
f3b3ae8752adc5 Kent Gibson 2020-06-23 1075 }
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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