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Validate PKWARE compressed size before header subtraction #520

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Validate PKWARE compressed size before header subtraction #520

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15 changes: 15 additions & 0 deletions lib/zip_source_pkware_decode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -53,6 +53,7 @@ static void trad_pkware_free(struct trad_pkware *);
zip_source_t *zip_source_pkware_decode(zip_t *za, zip_source_t *src, zip_uint16_t em, int flags, const char *password) {
struct trad_pkware *ctx;
zip_source_t *s2;
zip_stat_t st;

if (password == NULL || src == NULL || em != ZIP_EM_TRAD_PKWARE) {
zip_error_set(&za->error, ZIP_ER_INVAL, 0);
Expand All @@ -63,6 +64,16 @@ zip_source_t *zip_source_pkware_decode(zip_t *za, zip_source_t *src, zip_uint16_
return NULL;
}

if (zip_source_stat(src, &st) != 0) {
zip_error_set_from_source(&za->error, src);
return NULL;
}

if ((st.valid & ZIP_STAT_COMP_SIZE) == 0 || st.comp_size < ZIP_CRYPTO_PKWARE_HEADERLEN) {
zip_error_set(&za->error, ZIP_ER_OPNOTSUPP, 0);
return NULL;
}

if ((ctx = trad_pkware_new(password, &za->error)) == NULL) {
return NULL;
}
Expand Down Expand Up @@ -160,6 +171,10 @@ static zip_int64_t pkware_decrypt(zip_source_t *src, void *ud, void *data, zip_u
st->encryption_method = ZIP_EM_NONE;
st->valid |= ZIP_STAT_ENCRYPTION_METHOD;
if (st->valid & ZIP_STAT_COMP_SIZE) {
if (st->comp_size < ZIP_CRYPTO_PKWARE_HEADERLEN) {
zip_error_set(&ctx->error, ZIP_ER_INCONS, ZIP_ER_DETAIL_CDIR_ENTRY_INVALID);
return -1;
}
st->comp_size -= ZIP_CRYPTO_PKWARE_HEADERLEN;
}

Expand Down