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- From 2f533a89a8dfcacbf2c9dbc77d910f111f24bf33 Mon Sep 17 00:00:00 2001
- From: Daniel Axtens <dja@axtens.net>
- Date: Fri, 22 Jan 2021 17:10:48 +1100
- Subject: [PATCH] commands/menuentry: Fix quoting in setparams_prefix()
- Commit 9acdcbf32542 (use single quotes in menuentry setparams command)
- says that expressing a quoted single quote will require 3 characters. It
- actually requires (and always did require!) 4 characters:
- str: a'b => a'\''b
- len: 3 => 6 (2 for the letters + 4 for the quote)
- This leads to not allocating enough memory and thus out of bounds writes
- that have been observed to cause heap corruption.
- Allocate 4 bytes for each single quote.
- Commit 22e7dbb2bb81 (Fix quoting in legacy parser.) does the same
- quoting, but it adds 3 as extra overhead on top of the single byte that
- the quote already needs. So it's correct.
- Fixes: 9acdcbf32542 (use single quotes in menuentry setparams command)
- Fixes: CVE-2021-20233
- Reported-by: Daniel Axtens <dja@axtens.net>
- Signed-off-by: Daniel Axtens <dja@axtens.net>
- Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
- Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
- ---
- grub-core/commands/menuentry.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
- diff --git a/grub-core/commands/menuentry.c b/grub-core/commands/menuentry.c
- index 9164df7..720e6d8 100644
- --- a/grub-core/commands/menuentry.c
- +++ b/grub-core/commands/menuentry.c
- @@ -230,7 +230,7 @@ setparams_prefix (int argc, char **args)
- len += 3; /* 3 = 1 space + 2 quotes */
- p = args[i];
- while (*p)
- - len += (*p++ == '\'' ? 3 : 1);
- + len += (*p++ == '\'' ? 4 : 1);
- }
-
- result = grub_malloc (len + 2);
- --
- 2.14.2
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