Andrew Geissler | 90fd73c | 2021-03-05 15:25:55 -0600 | [diff] [blame] | 1 | Description: [CVE-2021-26937] Fix out of bounds array access |
| 2 | Author: Michael Schrรถder <mls@suse.de> |
| 3 | Bug-Debian: https://bugs.debian.org/982435 |
| 4 | Bug: https://savannah.gnu.org/bugs/?60030 |
| 5 | Bug: https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00000.html |
| 6 | Bug-OSS-Security: https://www.openwall.com/lists/oss-security/2021/02/09/3 |
| 7 | Origin: https://lists.gnu.org/archive/html/screen-devel/2021-02/msg00010.html |
| 8 | |
| 9 | CVE: CVE-2021-26937 |
| 10 | Upstream-Status: Pending |
| 11 | Signed-off-by: Scott Murray <scott.murray@konsulko.com> |
| 12 | |
| 13 | --- a/encoding.c |
| 14 | +++ b/encoding.c |
| 15 | @@ -43,7 +43,7 @@ |
| 16 | # ifdef UTF8 |
| 17 | static int recode_char __P((int, int, int)); |
| 18 | static int recode_char_to_encoding __P((int, int)); |
| 19 | -static void comb_tofront __P((int, int)); |
| 20 | +static void comb_tofront __P((int)); |
| 21 | # ifdef DW_CHARS |
| 22 | static int recode_char_dw __P((int, int *, int, int)); |
| 23 | static int recode_char_dw_to_encoding __P((int, int *, int)); |
| 24 | @@ -1263,6 +1263,8 @@ |
| 25 | {0x30000, 0x3FFFD}, |
| 26 | }; |
| 27 | |
| 28 | + if (c >= 0xdf00 && c <= 0xdfff) |
| 29 | + return 1; /* dw combining sequence */ |
| 30 | return ((bisearch(c, wide, sizeof(wide) / sizeof(struct interval) - 1)) || |
| 31 | (cjkwidth && |
| 32 | bisearch(c, ambiguous, |
| 33 | @@ -1330,11 +1332,12 @@ |
| 34 | } |
| 35 | |
| 36 | static void |
| 37 | -comb_tofront(root, i) |
| 38 | -int root, i; |
| 39 | +comb_tofront(i) |
| 40 | +int i; |
| 41 | { |
| 42 | for (;;) |
| 43 | { |
| 44 | + int root = i >= 0x700 ? 0x801 : 0x800; |
| 45 | debug1("bring to front: %x\n", i); |
| 46 | combchars[combchars[i]->prev]->next = combchars[i]->next; |
| 47 | combchars[combchars[i]->next]->prev = combchars[i]->prev; |
| 48 | @@ -1396,9 +1399,9 @@ |
| 49 | { |
| 50 | /* full, recycle old entry */ |
| 51 | if (c1 >= 0xd800 && c1 < 0xe000) |
| 52 | - comb_tofront(root, c1 - 0xd800); |
| 53 | + comb_tofront(c1 - 0xd800); |
| 54 | i = combchars[root]->prev; |
| 55 | - if (c1 == i + 0xd800) |
| 56 | + if (i == 0x800 || i == 0x801 || c1 == i + 0xd800) |
| 57 | { |
| 58 | /* completely full, can't recycle */ |
| 59 | debug("utf8_handle_comp: completely full!\n"); |
| 60 | @@ -1422,7 +1425,7 @@ |
| 61 | mc->font = (i >> 8) + 0xd8; |
| 62 | mc->fontx = 0; |
| 63 | debug3("combinig char %x %x -> %x\n", c1, c, i + 0xd800); |
| 64 | - comb_tofront(root, i); |
| 65 | + comb_tofront(i); |
| 66 | } |
| 67 | |
| 68 | #else /* !UTF8 */ |