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Commit d8dc5b3f authored by Dominik Laskowski's avatar Dominik Laskowski
Browse files

screencap: Fix parsing of display IDs 

The underlying type of DisplayId is uint64_t, but screencap parsed the
IDs as signed 64-bit, invoking undefined behavior for out-of-range IDs.
In practice, out-of-range IDs were clamped, so SF failed to find them.

Fixes: 302580952
Test: screencap works for virtual display on Felix
Change-Id: I09a863d0c68dbb857b6f756b51159e5e3d853f5d
parent fa76ad2f

cmds/screencap/screencap.cpp

+12 −3
Original line number Diff line number Diff line
@@ -142,13 +142,22 @@ int main(int argc, char** argv) 
            case 'p':

                png = true;

                break;

            case 'd':

                displayIdOpt = DisplayId::fromValue(atoll(optarg));

            case 'd': {

                errno = 0;

                char* end = nullptr;

                const uint64_t id = strtoull(optarg, &end, 10);

                if (!end || *end != '\0' || errno == ERANGE) {

                    fprintf(stderr, "Invalid display ID: Out of range [0, 2^64).\n");

                    return 1;

                }



                displayIdOpt = DisplayId::fromValue(id);

                if (!displayIdOpt) {

                    fprintf(stderr, "Invalid display ID: %s\n", optarg);

                    fprintf(stderr, "Invalid display ID: Incorrect encoding.\n");

                    return 1;

                }

                break;

            }

            case '?':

            case 'h':

                if (ids.size() == 1) {