[PATCH v2] usb: gadget: f_mass_storage: fix null pointer dereference in fsg_common_set_num_buffers()
Jeffin Philip <[email protected]>
| Newsgroups | gmane.linux.usb.general,gmane.linux.kernel,gmane.linux.kernel.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: syzbot+791be35f1fbcc85d06d7-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org
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