In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()<\/p>\n
When fbcon_do_set_font() fails (e.g., due to a memory allocation failure
\ninside vc_resize() under heavy memory pressure), it jumps to the `err_out`
\nlabel to roll back the console state. However, the current rollback logic
\nforgets to restore the `hi_font` state, leading to a severe state machine
\ncorruption.<\/p>\n
Earlier in the function, `set_vc_hi_font()` might be called to change
\n`vc->vc_hi_font_mask` and mutate the screen buffer. If `vc_resize()`
\nsubsequently fails, the `err_out` path restores `vc_font.charcount`
\nbut entirely skips rolling back the `vc_hi_font_mask` and the screen
\nbuffer.<\/p>\n
This mismatch leaves the terminal in a desynchronized state. Because
\n`vc_hi_font_mask` remains set, the VT subsystem will still accept
\ncharacter indices greater than 255 from userspace and write them to the
\nscreen buffer. Subsequent rendering calls (e.g., `fbcon_putcs()`) will
\nthen use these inflated indices to access the reverted, 256-character
\nfont array, leading to a deterministic out-of-bounds read and potential
\nkernel memory disclosure.<\/p>\n
Fix this by adding the missing rollback logic for the `hi_font` mask
\nand screen buffer in the error path.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fbdev: fbcon: fix out-of-bounds read in err_out of fbcon_do_set_font()<\/p>\n
When fbcon_do_set_font() fails (e.g., due to a memory alloc<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-14870","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/14870","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=14870"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14870"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14870"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}