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Commit f2bac04e authored by Sami Tolvanen's avatar Sami Tolvanen
Browse files

Add error and range checks to parse_range 

Only trusted input is passed to parse_range, but check for invalid
input to catch possible problems in transfer lists.

Bug: 21033983
Bug: 21034030
Bug: 21034172
Bug: 21034406
Change-Id: Ia17537a2d23d5f701522fbc42ed38924e1ee3366
parent 3badd563

updater/blockimg.c

+71 −10
Original line number Diff line number Diff line
@@ -60,30 +60,91 @@ typedef struct { 
    int pos[0];

} RangeSet;



#define RANGESET_MAX_POINTS \

    ((int)((INT_MAX / sizeof(int)) - sizeof(RangeSet)))



static RangeSet* parse_range(char* text) {

    char* save;

    int num;

    num = strtol(strtok_r(text, ",", &save), NULL, 0);

    char* token;

    int i, num;

    long int val;

    RangeSet* out = NULL;

    size_t bufsize;



    RangeSet* out = malloc(sizeof(RangeSet) + num * sizeof(int));

    if (out == NULL) {

        fprintf(stderr, "failed to allocate range of %zu bytes\n",

                sizeof(RangeSet) + num * sizeof(int));

        exit(1);

    if (!text) {

        goto err;

    }



    token = strtok_r(text, ",", &save);



    if (!token) {

        goto err;

    }



    val = strtol(token, NULL, 0);



    if (val < 2 || val > RANGESET_MAX_POINTS) {

        goto err;

    } else if (val % 2) {

        goto err; // must be even

    }



    num = (int) val;

    bufsize = sizeof(RangeSet) + num * sizeof(int);



    out = malloc(bufsize);



    if (!out) {

        fprintf(stderr, "failed to allocate range of %zu bytes\n", bufsize);

        goto err;

    }



    out->count = num / 2;

    out->size = 0;

    int i;



    for (i = 0; i < num; ++i) {

        out->pos[i] = strtol(strtok_r(NULL, ",", &save), NULL, 0);

        token = strtok_r(NULL, ",", &save);



        if (!token) {

            goto err;

        }



        val = strtol(token, NULL, 0);



        if (val < 0 || val > INT_MAX) {

            goto err;

        }



        out->pos[i] = (int) val;



        if (i % 2) {

            if (out->pos[i - 1] >= out->pos[i]) {

                goto err; // empty or negative range

            }



            if (out->size > INT_MAX - out->pos[i]) {

                goto err; // overflow

            }



            out->size += out->pos[i];

        } else {

            if (out->size < 0) {

                goto err;

            }



            out->size -= out->pos[i];

        }

    }



    if (out->size <= 0) {

        goto err;

    }



    return out;



err:

    fprintf(stderr, "failed to parse range '%s'\n", text ? text : "NULL");

    exit(1);

}



static int range_overlaps(RangeSet* r1, RangeSet* r2) {