hidraw: fix number of bytes to copy from uevent in parse_uevent_info #497
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Commit 5c9f147 (libusb#432) replaced a call to strdup with an explicit memcpy to a buffer on the stack. However, it incorrectly used the buffer size, instead of the clamped uevent length, as the argument to memcpy, resulting in reads past the end of uevent: $ valgrind -q hidtest/hidtest_hidraw 1>/dev/null ==51900== Invalid read of size 8 ==51900== at 0x48571D5: parse_uevent_info (hid.c:496) ==51900== by 0x48574F2: create_device_info_for_device (hid.c:578) ==51900== by 0x4857ED7: hid_enumerate (hid.c:876) ==51900== by 0x1094CE: main (test.c:105) ==51900== Address 0x4b6c1a0 is 7 bytes after a block of size 185 alloc'd ==51900== at 0x4846CC3: realloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so) ==51900== by 0x4AA0E45: UnknownInlinedFun (fileio.c:534) ==51900== by 0x4AA0E45: read_virtual_file_at.constprop.0 (fileio.c:572) ==51900== by 0x4A9D37C: UnknownInlinedFun (fileio.h:74) ==51900== by 0x4A9D37C: UnknownInlinedFun (fileio.h:77) ==51900== by 0x4A9D37C: sd_device_get_sysattr_value (sd-device.c:2318) ==51900== by 0x4A8B0D1: udev_device_get_sysattr_value (libudev-device.c:747) ==51900== by 0x48574BE: create_device_info_for_device (hid.c:578) ==51900== by 0x4857ED7: hid_enumerate (hid.c:876) ==51900== by 0x1094CE: main (test.c:105) ==51900== Fix this by using uevent_len as the argument to memcpy. Calling strndupa was considered but abandoned, as it is not standard. Fixes: 5c9f147 (libusb#432) Fixes: 4779d63
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That is a good catch, thanks. |
The buffer size, instead of the clamped uevent length, was being used as the argument to memcpy, allowing reads past the end of uevent.
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Sure! Done. |
Youw
approved these changes
Jan 9, 2023
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This is no-workaround and high-risk bug introdecud in the latest release. |
netfab
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to netfab/overlay
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Jan 10, 2023
hotfix release : libusb/hidapi#497 Signed-off-by: Fabrice Delliaux <netbox253@gmail.com>
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Commit 5c9f147 (#432) replaced a call to strdup with an explicit memcpy to a buffer on the stack.
However, it incorrectly used the buffer size, instead of the clamped uevent length, as the argument to memcpy, resulting in reads past the end of uevent:
Fix this by using uevent_len as the argument to memcpy.
Calling strndupa was considered but abandoned, as it is not standard.
Fixes: 5c9f147 (#432)
Fixes: 4779d63