[sfnt, type42] Correct previous commit.

Really fix https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=42773.

* src/sfnt/ttload.c (check_table_dir): Revert change.

* src/type42/t42.parse.c (t42_parse_sfnts): Don't use `FT_QREALLOC` but
`FT_REALLOC` for setting up `ttf_data` to avoid uninitialized memory access
while handling malformed TrueType fonts later on.
This commit is contained in:
Werner Lemberg 2022-01-08 10:28:19 +01:00
parent bf9b1ef905
commit 7a493e3a40
2 changed files with 11 additions and 4 deletions

View File

@ -200,7 +200,7 @@
for ( nn = 0; nn < sfnt->num_tables; nn++ )
{
TT_TableRec table = { 0, 0, 0, 0 };
TT_TableRec table;
if ( FT_STREAM_READ_FIELDS( table_dir_entry_fields, &table ) )

View File

@ -718,7 +718,9 @@
goto Fail;
}
if ( FT_QREALLOC( face->ttf_data, 12, face->ttf_size ) )
/* To handle bad fonts with an invalid table directory */
/* we don't use `FT_QREALLOC` here. */
if ( FT_REALLOC( face->ttf_data, 12, face->ttf_size ) )
goto Fail;
}
/* fall through */
@ -767,8 +769,13 @@
FT_TRACE2(( " allocating %ld bytes\n", face->ttf_size + 1 ));
FT_TRACE2(( "\n" ));
if ( FT_QREALLOC( face->ttf_data, 12 + 16 * num_tables,
face->ttf_size + 1 ) )
/* To handle bad fonts we don't use `FT_QREALLOC` here: */
/* chances are high that due to incorrect values in the */
/* table directory the computation of `ttf_size` would be */
/* incorrect otherwise, causing run-time errors because of */
/* accessing uninitialized memory. */
if ( FT_REALLOC( face->ttf_data, 12 + 16 * num_tables,
face->ttf_size + 1 ) )
goto Fail;
}
/* fall through */