Fix #53467: Phar cannot compress large archives

When Phars are flushed, a new temporary file is created for each entry
which should be compressed, and the `compressed_filesize` is retrieved.
Afterwards, the Phar manifest is written, and only after that the files
are copied to the actual Phar.  So for each such entry there is an open
temp file, what easily exceeds the limit.

Therefore, we use a single temporary file for all entries, and store
the start offset in the otherwise unused `header_offset` member.  We
ensure that the `cfp` members are properly set to NULL even if flushing
fails, to avoid use after free scenarios.

This solution is based on a suggestion by @lserni[1].

Closes GH-6643.

[1] <https://github.com/box-project/box2/issues/80#issuecomment-77147371>

diff --git a/NEWS b/NEWS
index 9ca7f5624b021ea664f344e91a408642d543bfed..0ef6168f56599204b43bb835b60a1af1efab334c 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -9,6 +9,7 @@ PHP                                                                        NEWS
   . Fixed bug #75850 (Unclear error message wrt. __halt_compiler() w/o
     semicolon) (cmb)
   . Fixed bug #70091 (Phar does not mark UTF-8 filenames in ZIP archives). (cmb)
+  . Fixed bug #53467 (Phar cannot compress large archives). (cmb, lserni)
 
 - Standard:
   . Fixed bug #80654 (file_get_contents() maxlen fails above (2**31)-1 bytes).

diff --git a/ext/phar/phar.c b/ext/phar/phar.c
index 2749283ff5a3775361d70ca138640db23f80ebaa..7cb1b06363874cf34eeb9bc8be5b515d68953984 100644 (file)
--- a/ext/phar/phar.c
+++ b/ext/phar/phar.c
@@ -2508,6 +2508,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
        smart_str main_metadata_str = {0};
        int free_user_stub, free_fp = 1, free_ufp = 1;
        int manifest_hack = 0;
+       php_stream *shared_cfp = NULL;
 
        if (phar->is_persistent) {
                if (error) {
@@ -2788,10 +2789,13 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                        return EOF;
                }
 
-               /* create new file that holds the compressed version */
+               /* create new file that holds the compressed versions */
                /* work around inability to specify freedom in write and strictness
                in read count */
-               entry->cfp = php_stream_fopen_tmpfile();
+               if (shared_cfp == NULL) {
+                       shared_cfp = php_stream_fopen_tmpfile();
+               }
+               entry->cfp = shared_cfp;
                if (!entry->cfp) {
                        if (error) {
                                spprintf(error, 0, "unable to create temporary file");
@@ -2800,8 +2804,11 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                                php_stream_close(oldfile);
                        }
                        php_stream_close(newfile);
-                       return EOF;
+                       goto cleanup;
                }
+               /* for real phars, header_offset is unused; we misuse it here to store the offset in the temp file */
+               ZEND_ASSERT(entry->header_offset == 0);
+               entry->header_offset = php_stream_tell(entry->cfp);
                php_stream_flush(file);
                if (-1 == phar_seek_efp(entry, 0, SEEK_SET, 0, 0)) {
                        if (closeoldfile) {
@@ -2811,7 +2818,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                        if (error) {
                                spprintf(error, 0, "unable to seek to start of file \"%s\" while creating new phar \"%s\"", entry->filename, phar->fname);
                        }
-                       return EOF;
+                       goto cleanup;
                }
                php_stream_filter_append((&entry->cfp->writefilters), filter);
                if (SUCCESS != php_stream_copy_to_stream_ex(file, entry->cfp, entry->uncompressed_filesize, NULL)) {
@@ -2822,15 +2829,14 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                        if (error) {
                                spprintf(error, 0, "unable to copy compressed file contents of file \"%s\" while creating new phar \"%s\"", entry->filename, phar->fname);
                        }
-                       return EOF;
+                       goto cleanup;
                }
                php_stream_filter_flush(filter, 1);
                php_stream_flush(entry->cfp);
                php_stream_filter_remove(filter, 1);
                php_stream_seek(entry->cfp, 0, SEEK_END);
-               entry->compressed_filesize = (uint32_t) php_stream_tell(entry->cfp);
+               entry->compressed_filesize = ((uint32_t) php_stream_tell(entry->cfp)) - entry->header_offset;
                /* generate crc on compressed file */
-               php_stream_rewind(entry->cfp);
                entry->old_flags = entry->flags;
                entry->is_modified = 1;
                global_flags |= (entry->flags & PHAR_ENT_COMPRESSION_MASK);
@@ -2886,7 +2892,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                        spprintf(error, 0, "unable to write manifest header of new phar \"%s\"", phar->fname);
                }
 
-               return EOF;
+               goto cleanup;
        }
 
        phar->alias_len = restore_alias_len;
@@ -2907,7 +2913,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                        spprintf(error, 0, "unable to write manifest meta-data of new phar \"%s\"", phar->fname);
                }
 
-               return EOF;
+               goto cleanup;
        }
        smart_str_free(&main_metadata_str);
 
@@ -2942,7 +2948,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                                        spprintf(error, 0, "unable to write filename of file \"%s\" to manifest of new phar \"%s\"", entry->filename, phar->fname);
                                }
                        }
-                       return EOF;
+                       goto cleanup;
                }
 
                /* set the manifest meta-data:
@@ -2975,7 +2981,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                                spprintf(error, 0, "unable to write temporary manifest of file \"%s\" to manifest of new phar \"%s\"", entry->filename, phar->fname);
                        }
 
-                       return EOF;
+                       goto cleanup;
                }
        } ZEND_HASH_FOREACH_END();
        /* Hack - see bug #65028, add padding byte to the end of the manifest */
@@ -2991,7 +2997,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                                spprintf(error, 0, "unable to write manifest padding byte");
                        }
 
-                       return EOF;
+                       goto cleanup;
                }
        }
 
@@ -3004,7 +3010,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
 
                if (entry->cfp) {
                        file = entry->cfp;
-                       php_stream_rewind(file);
+                       php_stream_seek(file, entry->header_offset, SEEK_SET);
                } else {
                        file = phar_get_efp(entry, 0);
                        if (-1 == phar_seek_efp(entry, 0, SEEK_SET, 0, 0)) {
@@ -3015,7 +3021,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                                if (error) {
                                        spprintf(error, 0, "unable to seek to start of file \"%s\" while creating new phar \"%s\"", entry->filename, phar->fname);
                                }
-                               return EOF;
+                               goto cleanup;
                        }
                }
 
@@ -3027,7 +3033,7 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                        if (error) {
                                spprintf(error, 0, "unable to seek to start of file \"%s\" while creating new phar \"%s\"", entry->filename, phar->fname);
                        }
-                       return EOF;
+                       goto cleanup;
                }
 
                /* this will have changed for all files that have either changed compression or been modified */
@@ -3044,14 +3050,14 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                                spprintf(error, 0, "unable to write contents of file \"%s\" to new phar \"%s\"", entry->filename, phar->fname);
                        }
 
-                       return EOF;
+                       goto cleanup;
                }
 
                entry->is_modified = 0;
 
                if (entry->cfp) {
-                       php_stream_close(entry->cfp);
                        entry->cfp = NULL;
+                       entry->header_offset = 0;
                }
 
                if (entry->fp_type == PHAR_MOD) {
@@ -3067,6 +3073,11 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                }
        } ZEND_HASH_FOREACH_END();
 
+       if (shared_cfp != NULL) {
+               php_stream_close(shared_cfp);
+               shared_cfp = NULL;
+       }
+
        /* append signature */
        if (global_flags & PHAR_HDR_SIGNATURE) {
                char sig_buf[4];
@@ -3196,6 +3207,19 @@ int phar_flush(phar_archive_data *phar, char *user_stub, zend_long len, int conv
                return EOF;
        }
 
+       return EOF;
+
+cleanup:
+       if (shared_cfp != NULL) {
+               php_stream_close(shared_cfp);
+       }
+       ZEND_HASH_FOREACH_PTR(&phar->manifest, entry) {
+               if (entry->cfp) {
+                       entry->cfp = NULL;
+                       entry->header_offset = 0;
+               }
+       } ZEND_HASH_FOREACH_END();
+
        return EOF;
 }
 /* }}} */