[PATCH v2] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()
Jeffin Philip <[email protected]>
| Newsgroups | org.kernel.vger.linux-usb,org.kernel.vger.linux-kernel,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
Previously fsg_num_buffers_validate() was removed as it was not necessary due to Kconfig setting the limits for n from 2 to 256 with default as 2. However, setting the page content in such a way that kstrtou8() reflects n value as either 0 or 1 bypasses these restrictions leading to a null pointer dereference if n is 0. Fix this by adding a check for n < 2 and returning -EINVAL if n is either 0 or 1 consistent with Kconfig logic. Reported-by: [email protected] Closes: https://syzkaller.appspot.com/bug?extid=791be35f1fbcc85d06d7 Fixes: fe5a6c48fd95 ("usb: gadget: storage: get rid of fsg_num_buffers_validate()") Cc: [email protected] Signed-off-by: Jeffin Philip <[email protected]> --- Changes in v2: - Change check from n = 0 to n < 2 consistent with Kconfig logic --- drivers/usb/gadget/function/f_mass_storage.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c index a50743caf083..4e743be220cc 100644 --- a/drivers/usb/gadget/function/f_mass_storage.c +++ b/drivers/usb/gadget/function/f_mass_storage.c @@ -2747,6 +2747,9 @@ int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n) struct fsg_buffhd *bh, *buffhds; int i; + if (n < 2) + return -EINVAL; + buffhds = kzalloc_objs(*buffhds, n); if (!buffhds) return -ENOMEM; -- 2.55.0