diff options
Diffstat (limited to 'meta/recipes-bsp/grub/files/CVE-2020-10713.patch')
| -rw-r--r-- | meta/recipes-bsp/grub/files/CVE-2020-10713.patch | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/meta/recipes-bsp/grub/files/CVE-2020-10713.patch b/meta/recipes-bsp/grub/files/CVE-2020-10713.patch new file mode 100644 index 0000000000..c507ed3ea8 --- /dev/null +++ b/meta/recipes-bsp/grub/files/CVE-2020-10713.patch @@ -0,0 +1,73 @@ +From a4d3fbdff1e3ca8f87642af2ac8752c30c617a3e Mon Sep 17 00:00:00 2001 +From: Peter Jones <pjones@redhat.com> +Date: Wed, 15 Apr 2020 15:45:02 -0400 +Subject: yylex: Make lexer fatal errors actually be fatal + +When presented with a command that can't be tokenized to anything +smaller than YYLMAX characters, the parser calls YY_FATAL_ERROR(errmsg), +expecting that will stop further processing, as such: + + #define YY_DO_BEFORE_ACTION \ + yyg->yytext_ptr = yy_bp; \ + yyleng = (int) (yy_cp - yy_bp); \ + yyg->yy_hold_char = *yy_cp; \ + *yy_cp = '\0'; \ + if ( yyleng >= YYLMAX ) \ + YY_FATAL_ERROR( "token too large, exceeds YYLMAX" ); \ + yy_flex_strncpy( yytext, yyg->yytext_ptr, yyleng + 1 , yyscanner); \ + yyg->yy_c_buf_p = yy_cp; + +The code flex generates expects that YY_FATAL_ERROR() will either return +for it or do some form of longjmp(), or handle the error in some way at +least, and so the strncpy() call isn't in an "else" clause, and thus if +YY_FATAL_ERROR() is *not* actually fatal, it does the call with the +questionable limit, and predictable results ensue. + +Unfortunately, our implementation of YY_FATAL_ERROR() is: + + #define YY_FATAL_ERROR(msg) \ + do { \ + grub_printf (_("fatal error: %s\n"), _(msg)); \ + } while (0) + +The same pattern exists in yyless(), and similar problems exist in users +of YY_INPUT(), several places in the main parsing loop, +yy_get_next_buffer(), yy_load_buffer_state(), yyensure_buffer_stack, +yy_scan_buffer(), etc. + +All of these callers expect YY_FATAL_ERROR() to actually be fatal, and +the things they do if it returns after calling it are wildly unsafe. + +Fixes: CVE-2020-10713 + +Signed-off-by: Peter Jones <pjones@redhat.com> +Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com> + +Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=a4d3fbdff1e3ca8f87642af2ac8752c30c617a3e] +CVE: CVE-2020-10713 +Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com> +--- + grub-core/script/yylex.l | 4 ++-- + 1 file changed, 2 insertions(+), 2 deletions(-) + +diff --git a/grub-core/script/yylex.l b/grub-core/script/yylex.l +index 7b44c37b7..b7203c823 100644 +--- a/grub-core/script/yylex.l ++++ b/grub-core/script/yylex.l +@@ -37,11 +37,11 @@ + + /* + * As we don't have access to yyscanner, we cannot do much except to +- * print the fatal error. ++ * print the fatal error and exit. + */ + #define YY_FATAL_ERROR(msg) \ + do { \ +- grub_printf (_("fatal error: %s\n"), _(msg)); \ ++ grub_fatal (_("fatal error: %s\n"), _(msg));\ + } while (0) + + #define COPY(str, hint) \ +-- +cgit v1.2.1 + |