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05429983fa
commit da99466ac2 upstream.
This fixes a global out-of-bounds read access in the copy_buffer
function of the floppy driver.
The FDDEFPRM ioctl allows one to set the geometry of a disk. The sect
and head fields (unsigned int) of the floppy_drive structure are used to
compute the max_sector (int) in the make_raw_rw_request function. It is
possible to overflow the max_sector. Next, max_sector is passed to the
copy_buffer function and used in one of the memcpy calls.
An unprivileged user could trigger the bug if the device is accessible,
but requires a floppy disk to be inserted.
The patch adds the check for the .sect * .head multiplication for not
overflowing in the set_geometry function.
The bug was found by syzkaller.
Signed-off-by: Denis Efremov <efremov@ispras.ru>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
4678 lines
118 KiB
4678 lines
118 KiB