efi/libstub: prevent read overflow in find_file_option()

[ Upstream commit c4039b29fe9637e1135912813f830994af4c867f ]

If the buffer has slashes up to the end then this will read past the end
of the array.  I don't anticipate that this is an issue for many people
in real life, but it's the right thing to do and it makes static
checkers happy.

Fixes: 7a88a6227dc7 ("efi/libstub: Fix path separator regression")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Dan Carpenter 2021-04-23 14:48:31 +03:00 committed by Greg Kroah-Hartman
parent b828601c75
commit 951f8ef71d

View File

@ -103,7 +103,7 @@ static int find_file_option(const efi_char16_t *cmdline, int cmdline_len,
return 0;
/* Skip any leading slashes */
while (cmdline[i] == L'/' || cmdline[i] == L'\\')
while (i < cmdline_len && (cmdline[i] == L'/' || cmdline[i] == L'\\'))
i++;
while (--result_len > 0 && i < cmdline_len) {