diff options
author | Dan Carpenter <dan.carpenter@oracle.com> | 2019-08-21 10:24:56 +0300 |
---|---|---|
committer | Noralf Trønnes <noralf@tronnes.org> | 2019-08-26 14:50:55 +0200 |
commit | d72cf01f410aa09868d98b672f3f92328c96b32d (patch) | |
tree | a1e21abcd34b9e5d5a47d090cbb9314e303557ed /drivers | |
parent | 6dbe0c4b0fc0646442b2b1580d022404e582fd7b (diff) | |
download | linux-d72cf01f410aa09868d98b672f3f92328c96b32d.tar.bz2 |
drm/mipi-dbi: fix a loop in debugfs code
This code will likely crash if we try to do a zero byte write. The code
looks like this:
/* strip trailing whitespace */
for (i = count - 1; i > 0; i--)
if (isspace(buf[i]))
...
We're writing zero bytes so count = 0. You would think that "count - 1"
would be negative one, but because "i" is unsigned it is a large
positive numer instead. The "i > 0" condition is true and the "buf[i]"
access will be out of bounds.
The fix is to make "i" signed and now everything works as expected. The
upper bound of "count" is capped in __kernel_write() at MAX_RW_COUNT so
we don't have to worry about it being higher than INT_MAX.
Fixes: 02dd95fe3169 ("drm/tinydrm: Add MIPI DBI support")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[noralf: Adjust title]
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190821072456.GJ26957@mwanda
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/gpu/drm/drm_mipi_dbi.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c index 1961f713aaab..c4ee2709a6f3 100644 --- a/drivers/gpu/drm/drm_mipi_dbi.c +++ b/drivers/gpu/drm/drm_mipi_dbi.c @@ -1187,8 +1187,7 @@ static ssize_t mipi_dbi_debugfs_command_write(struct file *file, struct mipi_dbi_dev *dbidev = m->private; u8 val, cmd = 0, parameters[64]; char *buf, *pos, *token; - unsigned int i; - int ret, idx; + int i, ret, idx; if (!drm_dev_enter(&dbidev->drm, &idx)) return -ENODEV; |