media: gspca: UBSAN: shift-out-of-bounds in set_flicker
Subsystems (2)
PATCH v3 1/1 media: gspca: UBSAN: shift-out-of-bounds in set_flicker
From: Rajeshwar R Shinde <[email protected]>
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'
When the value of the variable "sd->params.exposure.gain" exceeds the number of bits in an int, a shift-out-of-bounds error occurs. The error is generated when the variable "currentexp" is left-shifted by more than 31 bits. In order to confirm the range is valid, the conditional expression was added.
---v1->v2
Changed the patchv2->v3
Changed the commit message
--- drivers/media/usb/gspca/cpia1.c | 2 ++ 1 file changed, 2 insertions(+)
drivers/media/usb/gspca/cpia1.c +2 -0
@@ -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 */
Signature · 6 lines
2.25.1 _______________________________________________ Linux-kernel-mentees mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
Quoted 13 lines · On Thu, Aug 24, 2023 at 02:27:31PM +0530, [email protected] wrote:
From: Rajeshwar R Shinde <[email protected]>
Syzkaller reported the following issue:
UBSAN: shift-out-of-bounds in drivers/media/usb/gspca/cpia1.c:1031:27shift exponent 245 is too large for 32-bit type 'int'
When the value of the variable "
sd->params.exposure.gain" exceeds the number of bits in an int, a shift-out-of-bounds error occurs. The error is generated when the variable "currentexp" is left-shifted by more than 31 bits. In order to confirm the range is valid, the conditional expression was added.
Quoted 4 lines
You have loads of trailing whitespace, please fix your editor to not do that.
Quoted 3 lines
---
v1->v2
Changed the patch
In what way? Be specific.
Quoted 2 lines
v2->v3
Changed the commit message
Again, be specific please. Otherwise all changes could be listed with these two sentances and that helps none of us out :(
Quoted 9 lines
--- drivers/media/usb/gspca/cpia1.c | 2 ++ 1 file changed, 2 insertions(+)drivers/media/usb/gspca/cpia1.c +0
-0
drivers/media/usb/gspca/cpia1.c static int set_flicker(struct gspca_dev *gspca_dev, int on, int apply) · line 1032
Quoted 5 lines
drivers/media/usb/gspca/cpia1.c +2
-0@@ -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 ;
Why is this still -1?
greg k-h
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