| Message ID | 20200113100132.ixpaymordi24n3av@kili.mountain (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] fbdev: potential information leak in do_fb_ioctl() | expand |
On 1/13/20 12:08 PM, Dan Carpenter wrote: > The "fix" struct has a 2 byte hole after ->ywrapstep and the > "fix = info->fix;" assignment doesn't necessarily clear it. It depends > on the compiler. The solution is just to replace the assignment with an > memcpy(). > > Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held") > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Patch queued for v5.6, thanks. Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics > --- > v2: Use memcpy() > > drivers/video/fbdev/core/fbmem.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c > index d04554959ea7..bb8d8dbc0461 100644 > --- a/drivers/video/fbdev/core/fbmem.c > +++ b/drivers/video/fbdev/core/fbmem.c > @@ -1115,7 +1115,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, > break; > case FBIOGET_FSCREENINFO: > lock_fb_info(info); > - fix = info->fix; > + memcpy(&fix, &info->fix, sizeof(fix)); > if (info->flags & FBINFO_HIDE_SMEM_START) > fix.smem_start = 0; > unlock_fb_info(info); >
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index d04554959ea7..bb8d8dbc0461 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1115,7 +1115,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, break; case FBIOGET_FSCREENINFO: lock_fb_info(info); - fix = info->fix; + memcpy(&fix, &info->fix, sizeof(fix)); if (info->flags & FBINFO_HIDE_SMEM_START) fix.smem_start = 0; unlock_fb_info(info);
The "fix" struct has a 2 byte hole after ->ywrapstep and the "fix = info->fix;" assignment doesn't necessarily clear it. It depends on the compiler. The solution is just to replace the assignment with an memcpy(). Fixes: 1f5e31d7e55a ("fbmem: don't call copy_from/to_user() with mutex held") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- v2: Use memcpy() drivers/video/fbdev/core/fbmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)