In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
HID: picolcd: clamp eeprom debugfs read to bytes actually received<\/p>\n
picolcd_debug_eeprom_read() trusts resp->raw_data[2] — a length byte
\nsupplied by the device in its REPORT_EE_DATA reply — clamped only to
\nthe caller’s read() count:<\/p>\n
\tret = resp->raw_data[2];
\n\tif (ret > s)
\n\t\tret = s;
\n\tif (copy_to_user(u, resp->raw_data+3, ret))<\/p>\n
It never checks resp->raw_size, the number of bytes picolcd_raw_event()
\nactually copied into the 64-byte raw_data[] of the kmalloc’d struct
\npicolcd_pending. A device (or a spoofed picoLCD) returning a length byte
\nof 0xff, read with a count >= 255, makes copy_to_user() read past
\nraw_data[] into adjacent slab memory and return it to userspace through
\nthe debugfs “eeprom” file:<\/p>\n
\tBUG: KASAN: slab-out-of-bounds in _copy_to_user
\n\tRead of size 255 … picolcd_debug_eeprom_read+0x214\/0x2f0 [hid_picolcd]<\/p>\n
The debug-dump path in the same file already validates the device length
\nbyte against the received size before trusting it; this read does not.
\nThe file is created S_IRUSR (root-only) and a crafted device is needed,
\nso it is neither unprivileged- nor remotely-triggerable.<\/p>\n
Clamp the copy length to resp->raw_size – 3 (the payload actually
\nreceived, minus the 3-byte header), floored at 0 for short replies.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
HID: picolcd: clamp eeprom debugfs read to bytes actually received<\/p>\n
picolcd_debug_eeprom_read() trusts resp->raw_data[2] — a lengt<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-21550","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/21550","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21550"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21550"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21550"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}