diff options
Diffstat (limited to 'debian/patches/cve_2022_2601/0008-font-Fix-integer-underflow-in-binary-search-of-char-.patch')
| -rw-r--r-- | debian/patches/cve_2022_2601/0008-font-Fix-integer-underflow-in-binary-search-of-char-.patch | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/debian/patches/cve_2022_2601/0008-font-Fix-integer-underflow-in-binary-search-of-char-.patch b/debian/patches/cve_2022_2601/0008-font-Fix-integer-underflow-in-binary-search-of-char-.patch new file mode 100644 index 0000000..0db8d15 --- /dev/null +++ b/debian/patches/cve_2022_2601/0008-font-Fix-integer-underflow-in-binary-search-of-char-.patch @@ -0,0 +1,86 @@ +From c140a086838e7c9af87842036f891b8393a8c4bc Mon Sep 17 00:00:00 2001 +From: Zhang Boyang <zhangboyang.id@gmail.com> +Date: Sun, 14 Aug 2022 18:09:38 +0800 +Subject: [PATCH 08/14] font: Fix integer underflow in binary search of char + index + +If search target is less than all entries in font->index then "hi" +variable is set to -1, which translates to SIZE_MAX and leads to errors. + +This patch fixes the problem by replacing the entire binary search code +with the libstdc++'s std::lower_bound() implementation. + +Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com> +Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> +--- + grub-core/font/font.c | 40 ++++++++++++++++++++++------------------ + 1 file changed, 22 insertions(+), 18 deletions(-) + +diff --git a/grub-core/font/font.c b/grub-core/font/font.c +index e4cb0d867..abd412a5e 100644 +--- a/grub-core/font/font.c ++++ b/grub-core/font/font.c +@@ -688,12 +688,12 @@ read_be_int16 (grub_file_t file, grub_int16_t * value) + static inline struct char_index_entry * + find_glyph (const grub_font_t font, grub_uint32_t code) + { +- struct char_index_entry *table; +- grub_size_t lo; +- grub_size_t hi; +- grub_size_t mid; ++ struct char_index_entry *table, *first, *end; ++ grub_size_t len; + + table = font->char_index; ++ if (table == NULL) ++ return NULL; + + /* Use BMP index if possible. */ + if (code < 0x10000 && font->bmp_idx) +@@ -706,25 +706,29 @@ find_glyph (const grub_font_t font, grub_uint32_t code) + */ + } + +- /* Do a binary search in `char_index', which is ordered by code point. */ +- lo = 0; +- hi = font->num_chars - 1; +- +- if (!table) +- return 0; ++ /* ++ * Do a binary search in char_index which is ordered by code point. ++ * The code below is the same as libstdc++'s std::lower_bound(). ++ */ ++ first = table; ++ len = font->num_chars; ++ end = first + len; + +- while (lo <= hi) ++ while (len > 0) + { +- mid = lo + (hi - lo) / 2; +- if (code < table[mid].code) +- hi = mid - 1; +- else if (code > table[mid].code) +- lo = mid + 1; ++ grub_size_t half = len >> 1; ++ struct char_index_entry *middle = first + half; ++ ++ if (middle->code < code) ++ { ++ first = middle + 1; ++ len = len - half - 1; ++ } + else +- return &table[mid]; ++ len = half; + } + +- return 0; ++ return (first < end && first->code == code) ? first : NULL; + } + + /* Get a glyph for the Unicode character CODE in FONT. The glyph is loaded +-- +2.30.2 + |