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Thu, 14 May 2020 13:45:09 +0000 (GMT) Subject: Re: [PATCH 11/20] amifb: get rid of pointless access_ok() calls To: Al Viro Cc: linux-kernel@vger.kernel.org, Linus Torvalds , linux-fsdevel@vger.kernel.org From: Bartlomiej Zolnierkiewicz Message-ID: <6f89732b-fba9-a947-6c61-5d1680747f3b@samsung.com> Date: Thu, 14 May 2020 15:45:09 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20200509234557.1124086-11-viro@ZenIV.linux.org.uk> Content-Language: en-US Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprEKsWRmVeSWpSXmKPExsWy7djP87pp3nvjDK5+ZLHYs/cki8XlXXPY LB71vWW3OP/3OKsDi8eJGb9ZPD5vkvPY9OQtUwBzFJdNSmpOZllqkb5dAlfG0p9bGAtWcVdc 6PjO1sA4kbOLkZNDQsBE4sibZqYuRi4OIYEVjBLd3XPYIJwvjBKT3lxlh3A+M0pMfDmJCaZl 3sFlUC3LGSU6P7xlhnDeMkosbO1n7GLk4BAW8JD4vbcepEFEQFXizqkzYM3MAoUSG+98ZQSx 2QSsJCa2rwKzeQXsJHbceMQCYrMA1f/73gZWLyoQIfHpwWFWiBpBiZMzn4DVcAo4SCw494IR Yqa4xK0n86Hmy0tsfzsH7B4JgX52iV9vVjNDXO0icfn1BKgPhCVeHd/CDmHLSPzfOZ8JomEd o8TfjhdQ3dsZJZZP/scGUWUtcefcLzaQz5gFNCXW79KHCDtKLH+6FuxhCQE+iRtvBSGO4JOY tG06M0SYV6KjTQiiWk1iw7INbDBru3auZJ7AqDQLyWuzkLwzC8k7sxD2LmBkWcUonlpanJue Wmycl1quV5yYW1yal66XnJ+7iRGYUk7/O/51B+O+P0mHGAU4GJV4eB9c3x0nxJpYVlyZe4hR goNZSYTXbz1QiDclsbIqtSg/vqg0J7X4EKM0B4uSOK/xopexQgLpiSWp2ampBalFMFkmDk6p BsZ41et10p0yrfV+5k2WZx/9q7Zd8NS+uT88rb5506L/HgzbmitVfvbrvLderBmTanzxTcm0 Yw6elk8b9APtPkmv/HNgyaNb1VcOfw09WNC1LXbjDO9/rLa33wpnnnJ11P3xY5FwPXfjp+Jw Qf7U6d/ieuZpNmnwcakdnD1t5kcB8ZxURfX3j5VYijMSDbWYi4oTAWfwInAlAwAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrEIsWRmVeSWpSXmKPExsVy+t/xe7qp3nvjDD5vNLLYs/cki8XlXXPY LB71vWW3OP/3OKsDi8eJGb9ZPD5vkvPY9OQtUwBzlJ5NUX5pSapCRn5xia1StKGFkZ6hpYWe kYmlnqGxeayVkamSvp1NSmpOZllqkb5dgl7G0p9bGAtWcVdc6PjO1sA4kbOLkZNDQsBEYt7B ZUxdjFwcQgJLGSW6jr1i72LkAErISBxfXwZRIyzx51oXG4gtJPCaUeLCYWmQEmEBD4nfe+tB wiICqhJ3Tp1hArGZBQol2qd+Z4EY+Y1RYsH1LmaQBJuAlcTE9lWMIDavgJ3EjhuPWEBsFqDm f9/bwJpFBSIkDu+YBVUjKHFy5hOwGk4BB4kF514wQixQl/gz7xIzhC0ucevJfKjF8hLb385h nsAoNAtJ+ywkLbOQtMxC0rKAkWUVo0hqaXFuem6xoV5xYm5xaV66XnJ+7iZGYPxsO/Zz8w7G SxuDDzEKcDAq8fBa3NodJ8SaWFZcmXuIUYKDWUmE1289UIg3JbGyKrUoP76oNCe1+BCjKdBz E5mlRJPzgbGdVxJvaGpobmFpaG5sbmxmoSTO2yFwMEZIID2xJDU7NbUgtQimj4mDU6qBMf7H 9Ltz6v0bp5e/38m+1jNWZ5dTUPBStUsGx53eFx5grT3GJux6WtGl6omYsqufzMstb38+eM1z e3HzHKmpX10sJsXdP7bDxZj9QoGKR+uq9Z9nsi+w6Dz+z4B7kUJT0fbXspw8m/Y4TNpx8eIJ IQaXT/+6+YVubphx7sR9LsUd4cb3mo4/OKvEUpyRaKjFXFScCADNsvlytQIAAA== X-CMS-MailID: 20200514134509eucas1p28834b8da955386c10df913d82582aadd X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20200509234610eucas1p258be307cde10392b26c322354db78a9b X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20200509234610eucas1p258be307cde10392b26c322354db78a9b References: <20200509234124.GM23230@ZenIV.linux.org.uk> <20200509234557.1124086-1-viro@ZenIV.linux.org.uk> <20200509234557.1124086-11-viro@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Al, On 5/10/20 1:45 AM, Al Viro wrote: > From: Al Viro > > addresses passed only to get_user() and put_user() This driver lacks checks for {get,put}_user() return values so it will now return 0 ("success") even if {get,put}_user() fails. Am I missing something? > Signed-off-by: Al Viro > --- > drivers/video/fbdev/amifb.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/drivers/video/fbdev/amifb.c b/drivers/video/fbdev/amifb.c > index 20e03e00b66d..6062104f3afb 100644 > --- a/drivers/video/fbdev/amifb.c > +++ b/drivers/video/fbdev/amifb.c > @@ -1855,8 +1855,6 @@ static int ami_get_var_cursorinfo(struct fb_var_cursorinfo *var, > var->yspot = par->crsr.spot_y; > if (size > var->height * var->width) > return -ENAMETOOLONG; > - if (!access_ok(data, size)) > - return -EFAULT; > delta = 1 << par->crsr.fmode; > lspr = lofsprite + (delta << 1); > if (par->bplcon0 & BPC0_LACE) > @@ -1935,8 +1933,6 @@ static int ami_set_var_cursorinfo(struct fb_var_cursorinfo *var, > return -EINVAL; > if (!var->height) > return -EINVAL; > - if (!access_ok(data, var->width * var->height)) > - return -EFAULT; > delta = 1 << fmode; > lofsprite = shfsprite = (u_short *)spritememory; > lspr = lofsprite + (delta << 1); > Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics