| Message ID | 20230824070630.8209-1-coolrrsh@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] UBSAN: shift-out-of-bounds in set_flicker | expand |
On Thu, Aug 24, 2023 at 12:36:30PM +0530, coolrrsh@gmail.com wrote: > From: Rajeshwar R Shinde <coolrrsh@gmail.com> > > Syzkaller reported the following issue: > > UBSAN: shift-out-of-bounds in drivers/media/usb/gspca/cpia1.c:1031:27 > shift exponent 245 is too large for 32-bit type 'int' > > shift-out-of-bounds error was triggered when variable > 'sd->params.exposure.gain' is greater than the number of bits of int. > When the variable 'currentexp' is left shifted beyond 31 bits then > the error is produced. Therefore added the conditional expression to > verify valid range. > > Tested via syzbot. > > Reported-by: syzbot+e27f3dbdab04e43b9f73@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/all/20230818164522.12806-1-coolrrsh@gmail.com > > Link: https://syzkaller.appspot.com/bug?extid=e27f3dbdab04e43b9f73 > > Signed-off-by: Rajeshwar R Shinde <coolrrsh@gmail.com> Please do not have blank lines beween these tags. You also have trailing whitespace in your changelog text :( > --- > v1->v2 > changed the patch > changed commit message and tested with checkpatch > > --- > drivers/media/usb/gspca/cpia1.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/media/usb/gspca/cpia1.c b/drivers/media/usb/gspca/cpia1.c > index 46ed95483e22..dafc522d5e7b 100644 > --- a/drivers/media/usb/gspca/cpia1.c > +++ b/drivers/media/usb/gspca/cpia1.c > @@ -1028,6 +1028,8 @@ static int set_flicker(struct gspca_dev *gspca_dev, int on, int apply) > sd->params.exposure.expMode = 2; > sd->exposure_status = EXPOSURE_NORMAL; > } > + if (sd->params.exposure.gain > 31) > + return -1; Do not make up error codes, please return a valid one and not a random negative number. Unless -1 is a valid value for this function? thanks, greg k-h
On 24/08/2023 09:13, Greg KH wrote: > On Thu, Aug 24, 2023 at 12:36:30PM +0530, coolrrsh@gmail.com wrote: >> From: Rajeshwar R Shinde <coolrrsh@gmail.com> >> >> Syzkaller reported the following issue: >> >> UBSAN: shift-out-of-bounds in drivers/media/usb/gspca/cpia1.c:1031:27 >> shift exponent 245 is too large for 32-bit type 'int' >> >> shift-out-of-bounds error was triggered when variable >> 'sd->params.exposure.gain' is greater than the number of bits of int. >> When the variable 'currentexp' is left shifted beyond 31 bits then >> the error is produced. Therefore added the conditional expression to >> verify valid range. >> >> Tested via syzbot. >> >> Reported-by: syzbot+e27f3dbdab04e43b9f73@syzkaller.appspotmail.com >> Closes: https://lore.kernel.org/all/20230818164522.12806-1-coolrrsh@gmail.com >> >> Link: https://syzkaller.appspot.com/bug?extid=e27f3dbdab04e43b9f73 >> >> Signed-off-by: Rajeshwar R Shinde <coolrrsh@gmail.com> > > Please do not have blank lines beween these tags. > > You also have trailing whitespace in your changelog text :( And please mention the driver name in your subject! E.g. something like: "media: gspca/cpia1: UBSAN: shift-out-of-bounds in set_flicker" That way I can actually know that this is a patch for a driver that I maintain. Regards, Hans > >> --- >> v1->v2 >> changed the patch >> changed commit message and tested with checkpatch >> >> --- >> drivers/media/usb/gspca/cpia1.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/media/usb/gspca/cpia1.c b/drivers/media/usb/gspca/cpia1.c >> index 46ed95483e22..dafc522d5e7b 100644 >> --- a/drivers/media/usb/gspca/cpia1.c >> +++ b/drivers/media/usb/gspca/cpia1.c >> @@ -1028,6 +1028,8 @@ static int set_flicker(struct gspca_dev *gspca_dev, int on, int apply) >> sd->params.exposure.expMode = 2; >> sd->exposure_status = EXPOSURE_NORMAL; >> } >> + if (sd->params.exposure.gain > 31) >> + return -1; > > Do not make up error codes, please return a valid one and not a random > negative number. Unless -1 is a valid value for this function? > > thanks, > > greg k-h
diff --git a/drivers/media/usb/gspca/cpia1.c b/drivers/media/usb/gspca/cpia1.c index 46ed95483e22..dafc522d5e7b 100644 --- a/drivers/media/usb/gspca/cpia1.c +++ b/drivers/media/usb/gspca/cpia1.c @@ -1028,6 +1028,8 @@ static int set_flicker(struct gspca_dev *gspca_dev, int on, int apply) sd->params.exposure.expMode = 2; sd->exposure_status = EXPOSURE_NORMAL; } + if (sd->params.exposure.gain > 31) + return -1; currentexp = currentexp << sd->params.exposure.gain; sd->params.exposure.gain = 0; /* round down current exposure to nearest value */