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ext/phar: 32-bit/64-bit divergence parsing tar entries with size ≥ 2 GiB (uint32_t → zend_off_t) #24242

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ext/phar: 32-bit/64-bit divergence parsing tar entries with size ≥ 2 GiB (uint32_t → zend_off_t) #24242

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56 changes: 42 additions & 14 deletions ext/phar/tar.c
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Original file line number Diff line number Diff line change
Expand Up @@ -144,6 +144,22 @@ static uint32_t phar_tar_checksum(const char *buf, size_t len) /* {{{ */
}
/* }}} */

static bool phar_tar_skip(php_stream *fp, uint32_t size, size_t totalsize)
{
zend_off_t offset = php_stream_tell(fp);

if (offset < 0
#if SIZEOF_ZEND_LONG == 4
|| size > ZEND_LONG_MAX
#endif
|| (size_t) offset > totalsize || size > totalsize - (size_t) offset) {
return false;
}

return php_stream_seek(fp, size, SEEK_CUR) == 0
&& php_stream_tell(fp) == offset + (zend_off_t) size;
}

bool phar_is_tar(const char *buf, const char *fname) /* {{{ */
{
tar_header *header = (tar_header *) buf;
Expand Down Expand Up @@ -260,6 +276,8 @@ zend_result phar_parse_tarfile(
char buf[512], *actual_alias = NULL, *p;
phar_entry_info entry = {0};
size_t pos = 0, read, totalsize;
zend_off_t end;
php_stream_statbuf ssb;
tar_header *hdr;
uint32_t sum1, sum2, size, old;
phar_archive_data *myphar, *actual;
Expand All @@ -270,9 +288,17 @@ zend_result phar_parse_tarfile(
*error = NULL;
}

php_stream_seek(fp, 0, SEEK_END);
totalsize = php_stream_tell(fp);
php_stream_seek(fp, 0, SEEK_SET);
if ((php_stream_stat(fp, &ssb) == 0 && ssb.sb.st_size > ZEND_LONG_MAX)
|| php_stream_seek(fp, 0, SEEK_END) != 0
|| (end = php_stream_tell(fp)) < 0
|| php_stream_seek(fp, 0, SEEK_SET) != 0) {
if (error) {
spprintf(error, 4096, "phar error: tar file \"%s\" exceeds the supported stream offset range", fname);
}
php_stream_close(fp);
return FAILURE;
}
totalsize = (size_t) end;
read = php_stream_read(fp, buf, sizeof(buf));

if (read != sizeof(buf)) {
Expand Down Expand Up @@ -324,7 +350,8 @@ zend_result phar_parse_tarfile(
}
}

if (!phar_tar_size(hdr->size, sizeof(hdr->size), &size)) {
if (!phar_tar_size(hdr->size, sizeof(hdr->size), &size)
|| (uint64_t) size + 511 > (uint64_t) ZEND_LONG_MAX) {
if (error) {
spprintf(error, 4096, "phar error: \"%s\" is a corrupted tar file (invalid entry size)", fname);
}
Expand Down Expand Up @@ -397,12 +424,17 @@ zend_result phar_parse_tarfile(
goto bail;
}
myphar->sig_len = sig_len;
php_stream_seek(fp, curloc + 512, SEEK_SET);
if (curloc < 0 || (size_t) curloc > totalsize
|| totalsize - (size_t) curloc < 512
|| php_stream_seek(fp, curloc + 512, SEEK_SET) != 0) {
if (error) {
spprintf(error, 4096, "phar error: \"%s\" is a corrupted tar file (truncated)", fname);
}
goto bail;
}
/* signature checked out, let's ensure this is the last file in the phar */
if (((hdr->typeflag == '\0') || (hdr->typeflag == TAR_FILE)) && size > 0) {
/* this is not good enough - seek succeeds even on truncated tars */
php_stream_seek(fp, 512, SEEK_CUR);
if ((uint32_t)php_stream_tell(fp) > totalsize) {
if (!phar_tar_skip(fp, 512, totalsize)) {
if (error) {
spprintf(error, 4096, "phar error: \"%s\" is a corrupted tar file (truncated)", fname);
}
Expand Down Expand Up @@ -470,9 +502,7 @@ zend_result phar_parse_tarfile(
/* skip blank stuff */
size = ((size+511)&~511) - size;

/* this is not good enough - seek succeeds even on truncated tars */
php_stream_seek(fp, size, SEEK_CUR);
if ((uint32_t)php_stream_tell(fp) > totalsize) {
if (!phar_tar_skip(fp, size, totalsize)) {
zend_string_free(entry.filename);
if (error) {
spprintf(error, 4096, "phar error: \"%s\" is a corrupted tar file (truncated)", fname);
Expand Down Expand Up @@ -663,9 +693,7 @@ zend_result phar_parse_tarfile(

if (phar_tar_type_has_data(hdr->typeflag) && size > 0) {
next:
/* this is not good enough - seek succeeds even on truncated tars */
php_stream_seek(fp, size, SEEK_CUR);
if ((uint32_t)php_stream_tell(fp) > totalsize) {
if (!phar_tar_skip(fp, size, totalsize)) {
if (error) {
spprintf(error, 4096, "phar error: \"%s\" is a corrupted tar file (truncated)", fname);
}
Expand Down
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