[media] vivid: fix smatch errors

The smatch utility got really confused about the grp % 22 code. Rewrote
it so it now understands that there really isn't a buffer overwrite.

vivid-rds-gen.c:82 vivid_rds_generate() error: buffer overflow 'rds->psname' 9 <= 43
vivid-rds-gen.c:83 vivid_rds_generate() error: buffer overflow 'rds->psname' 9 <= 42
vivid-rds-gen.c:89 vivid_rds_generate() error: buffer overflow 'rds->radiotext' 65 <= 84
vivid-rds-gen.c:90 vivid_rds_generate() error: buffer overflow 'rds->radiotext' 65 <= 85
vivid-rds-gen.c:92 vivid_rds_generate() error: buffer overflow 'rds->radiotext' 65 <= 86
vivid-rds-gen.c:93 vivid_rds_generate() error: buffer overflow 'rds->radiotext' 65 <= 87

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/platform/vivid/vivid-rds-gen.c b/drivers/media/platform/vivid/vivid-rds-gen.c
index c382343fdb66935eeb6bcb53e8e4898ce3c30721..53c7777dc0019701329a8e06336a4cbab2cbcc91 100644 (file)
--- a/drivers/media/platform/vivid/vivid-rds-gen.c
+++ b/drivers/media/platform/vivid/vivid-rds-gen.c
@@ -55,6 +55,7 @@ void vivid_rds_generate(struct vivid_rds_gen *rds)
 {
        struct v4l2_rds_data *data = rds->data;
        unsigned grp;
+       unsigned idx;
        struct tm tm;
        unsigned date;
        unsigned time;
@@ -73,24 +74,26 @@ void vivid_rds_generate(struct vivid_rds_gen *rds)
                case 0 ... 3:
                case 22 ... 25:
                case 44 ... 47: /* Group 0B */
+                       idx = (grp % 22) % 4;
                        data[1].lsb |= (rds->ta << 4) | (rds->ms << 3);
-                       data[1].lsb |= vivid_get_di(rds, grp % 22);
+                       data[1].lsb |= vivid_get_di(rds, idx);
                        data[1].msb |= 1 << 3;
                        data[2].lsb = rds->picode & 0xff;
                        data[2].msb = rds->picode >> 8;
                        data[2].block = V4L2_RDS_BLOCK_C_ALT | (V4L2_RDS_BLOCK_C_ALT << 3);
-                       data[3].lsb = rds->psname[2 * (grp % 22) + 1];
-                       data[3].msb = rds->psname[2 * (grp % 22)];
+                       data[3].lsb = rds->psname[2 * idx + 1];
+                       data[3].msb = rds->psname[2 * idx];
                        break;
                case 4 ... 19:
                case 26 ... 41: /* Group 2A */
-                       data[1].lsb |= (grp - 4) % 22;
+                       idx = ((grp - 4) % 22) % 16;
+                       data[1].lsb |= idx;
                        data[1].msb |= 4 << 3;
-                       data[2].msb = rds->radiotext[4 * ((grp - 4) % 22)];
-                       data[2].lsb = rds->radiotext[4 * ((grp - 4) % 22) + 1];
+                       data[2].msb = rds->radiotext[4 * idx];
+                       data[2].lsb = rds->radiotext[4 * idx + 1];
                        data[2].block = V4L2_RDS_BLOCK_C | (V4L2_RDS_BLOCK_C << 3);
-                       data[3].msb = rds->radiotext[4 * ((grp - 4) % 22) + 2];
-                       data[3].lsb = rds->radiotext[4 * ((grp - 4) % 22) + 3];
+                       data[3].msb = rds->radiotext[4 * idx + 2];
+                       data[3].lsb = rds->radiotext[4 * idx + 3];
                        break;
                case 56:
                        /*