diff options
| author | Jani Nikula <jani.nikula@intel.com> | 2023-02-16 22:44:58 +0200 |
|---|---|---|
| committer | Dmitry Osipenko <dmitry.osipenko@collabora.com> | 2023-02-27 02:58:37 +0300 |
| commit | 5bacecc3c56131c31f18b23d366f2184328fd9cf (patch) | |
| tree | 87fc3f9fd7ac7cc8a381b2d29b65a9132d9ed0a2 /drivers/gpu/drm/drm_displayid.c | |
| parent | 25c0e4062db43b790fbecf14d7cce6fc75fb3b26 (diff) | |
drm/displayid: add displayid_get_header() and check bounds better
Add a helper to get a pointer to struct displayid_header. To be
pedantic, add buffer overflow checks to not touch the base if that
itself would overflow.
Cc: Iaroslav Boliukin <iam@lach.pw>
Cc: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4a03b3a5132642d3cdb6d4c2641422955a917292.1676580180.git.jani.nikula@intel.com
Diffstat (limited to 'drivers/gpu/drm/drm_displayid.c')
| -rw-r--r-- | drivers/gpu/drm/drm_displayid.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_displayid.c b/drivers/gpu/drm/drm_displayid.c index 38ea8203df45..7d03159dc146 100644 --- a/drivers/gpu/drm/drm_displayid.c +++ b/drivers/gpu/drm/drm_displayid.c @@ -7,13 +7,28 @@ #include <drm/drm_edid.h> #include <drm/drm_print.h> +static const struct displayid_header * +displayid_get_header(const u8 *displayid, int length, int index) +{ + const struct displayid_header *base; + + if (sizeof(*base) > length - index) + return ERR_PTR(-EINVAL); + + base = (const struct displayid_header *)&displayid[index]; + + return base; +} + static int validate_displayid(const u8 *displayid, int length, int idx) { int i, dispid_length; u8 csum = 0; const struct displayid_header *base; - base = (const struct displayid_header *)&displayid[idx]; + base = displayid_get_header(displayid, length, idx); + if (IS_ERR(base)) + return PTR_ERR(base); DRM_DEBUG_KMS("base revision 0x%x, length %d, %d %d\n", base->rev, base->bytes, base->prod_id, base->ext_count); |