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* src/sfnt/ttcmap.c (tt_cmap2_validate): Fix potential numeric 

overflow.
This commit is contained in:
Werner Lemberg 2018-03-13 11:11:16 +01:00
parent 78cded2c5c
commit 5bd76524ef
2 changed files with 16 additions and 10 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2018-03-13 Werner Lemberg <wl@gnu.org>
* src/sfnt/ttcmap.c (tt_cmap2_validate): Fix potential numeric
overflow.
2018-03-13 Werner Lemberg <wl@gnu.org>
Fix cmap format 2 handling (#53320).

21
src/sfnt/ttcmap.c
View File

@ -222,10 +222,10 @@
/***** The following charmap lookup and iteration functions all *****/
/***** assume that the value `charcode' fulfills the following. *****/
/***** *****/
/***** - For one byte characters, `charcode' is simply the *****/
/***** - For one-byte characters, `charcode' is simply the *****/
/***** character code. *****/
/***** *****/
/***** - For two byte characters, `charcode' is the 2-byte *****/
/***** - For two-byte characters, `charcode' is the 2-byte *****/
/***** character code in big endian format. More precisely: *****/
/***** *****/
/***** (charcode >> 8) is the first byte value *****/
@ -252,11 +252,11 @@
/* subs 518 SUBHEAD[NSUBS] sub-headers array */
/* glyph_ids 518+NSUB*8 USHORT[] glyph ID array */
/* */
/* The `keys' table is used to map charcode high-bytes to sub-headers. */
/* The `keys' table is used to map charcode high bytes to sub-headers. */
/* The value of `NSUBS' is the number of sub-headers defined in the */
/* table and is computed by finding the maximum of the `keys' table. */
/* */
/* Note that for any n, `keys[n]' is a byte offset within the `subs' */
/* Note that for any `n', `keys[n]' is a byte offset within the `subs' */
/* table, i.e., it is the corresponding sub-header index multiplied */
/* by 8. */
/* */
@ -269,8 +269,8 @@
/* delta 4 SHORT see below */
/* offset 6 USHORT see below */
/* */
/* A sub-header defines, for each high-byte, the range of valid */
/* low-bytes within the charmap. Note that the range defined by `first' */
/* A sub-header defines, for each high byte, the range of valid */
/* low bytes within the charmap. Note that the range defined by `first' */
/* and `count' must be completely included in the interval [0..255] */
/* according to the specification. */
/* */
@ -360,7 +360,7 @@
/* check range within 0..255 */
if ( valid->level >= FT_VALIDATE_PARANOID )
{
if ( first_code >= 256 || first_code + code_count > 256 )
if ( first_code >= 256 || code_count > 256 - first_code )
FT_INVALID_DATA;
}
@ -412,7 +412,7 @@
{
FT_UInt char_lo = (FT_UInt)( char_code & 0xFF );
FT_UInt char_hi = (FT_UInt)( char_code >> 8 );
FT_Byte* p = table + 6; /* keys table */
FT_Byte* p = table + 6; /* keys table */
FT_Byte* subs = table + 518; /* subheaders table */
FT_Byte* sub;
@ -425,8 +425,8 @@
sub = subs; /* jump to first sub-header */
/* check that the sub-header for this byte is 0, which */
/* indicates that it is really a valid one-byte value */
/* Otherwise, return 0 */
/* indicates that it is really a valid one-byte value; */
/* otherwise, return 0 */
/* */
p += char_lo * 2;
if ( TT_PEEK_USHORT( p ) != 0 )
@ -445,6 +445,7 @@
if ( sub == subs )
goto Exit;
}
result = sub;
}