| Description: [CVE-2021-26937] Fix out of bounds array access |
| Author: Michael Schrรถder <mls@suse.de> |
| Bug-Debian: https://bugs.debian.org/982435 |
| Bug: https://savannah.gnu.org/bugs/?60030 |
| Bug: https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.html |
| Bug-OSS-Security: https://www.openwall.com/lists/oss-security/2021/02/09/3 |
| Origin: https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00010.html |
| |
| CVE: CVE-2021-26937 |
| Upstream-Status: Pending |
| Signed-off-by: Scott Murray <scott.murray@konsulko.com> |
| |
| --- a/encoding.c |
| +++ b/encoding.c |
| @@ -43,7 +43,7 @@ |
| # ifdef UTF8 |
| static int recode_char __P((int, int, int)); |
| static int recode_char_to_encoding __P((int, int)); |
| -static void comb_tofront __P((int, int)); |
| +static void comb_tofront __P((int)); |
| # ifdef DW_CHARS |
| static int recode_char_dw __P((int, int *, int, int)); |
| static int recode_char_dw_to_encoding __P((int, int *, int)); |
| @@ -1263,6 +1263,8 @@ |
| {0x30000, 0x3FFFD}, |
| }; |
| |
| + if (c >= 0xdf00 && c <= 0xdfff) |
| + return 1; /* dw combining sequence */ |
| return ((bisearch(c, wide, sizeof(wide) / sizeof(struct interval) - 1)) || |
| (cjkwidth && |
| bisearch(c, ambiguous, |
| @@ -1330,11 +1332,12 @@ |
| } |
| |
| static void |
| -comb_tofront(root, i) |
| -int root, i; |
| +comb_tofront(i) |
| +int i; |
| { |
| for (;;) |
| { |
| + int root = i >= 0x700 ? 0x801 : 0x800; |
| debug1("bring to front: %x\n", i); |
| combchars[combchars[i]->prev]->next = combchars[i]->next; |
| combchars[combchars[i]->next]->prev = combchars[i]->prev; |
| @@ -1396,9 +1399,9 @@ |
| { |
| /* full, recycle old entry */ |
| if (c1 >= 0xd800 && c1 < 0xe000) |
| - comb_tofront(root, c1 - 0xd800); |
| + comb_tofront(c1 - 0xd800); |
| i = combchars[root]->prev; |
| - if (c1 == i + 0xd800) |
| + if (i == 0x800 || i == 0x801 || c1 == i + 0xd800) |
| { |
| /* completely full, can't recycle */ |
| debug("utf8_handle_comp: completely full!\n"); |
| @@ -1422,7 +1425,7 @@ |
| mc->font = (i >> 8) + 0xd8; |
| mc->fontx = 0; |
| debug3("combinig char %x %x -> %x\n", c1, c, i + 0xd800); |
| - comb_tofront(root, i); |
| + comb_tofront(i); |
| } |
| |
| #else /* !UTF8 */ |