usb: gadget: f_midi2: fix use-after-free in string attribute show path

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f_midi2_opts_str_show() takes the string lock internally, but its
callers dereference the opts->info.<field> pointer before calling it,
outside the lock. This races with f_midi2_opts_str_store(), which
frees the old string under opts->lock when the attribute is written
concurrently, the show path can read a pointer that gets freed
before the lock inside str_show() is even taken.

Change f_midi2_opts_str_show() to take a pointer to the string field,
matching the existing pattern in f_midi2_opts_str_store(), and
dereference it only after the lock is held. Update all three callers
(iface_name, block name, and the EP string option macro) accordingly.

Reported-by: syzbot+2280f1cca5e6b0c353e4@syzkaller.appspotmail.com
Cc: stable <stable@kernel.org>
Closes: https://syzkaller.appspot.com/bug?extid=2280f1cca5e6b0c353e4
Signed-off-by: Ivy Lopez <skunkolee@gmail.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260816005434.34018-1-skunkolee@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Ivy Lopez 2026-08-15 18:54:33 -06:00 • committed by Greg Kroah-Hartman

parent e24e337035

commit fed0aa7c6e

1 changed files with 6 additions and 6 deletions

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drivers/usb/gadget/function/f_midi2.c

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