This is a note to let you know that I've just added the patch titled efi/libstub: Fix path separator regression to the 5.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: efi-libstub-fix-path-separator-regression.patch and it can be found in the queue-5.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 973597b4266c06ad4ccb1c6fe7d407fe5fa65733 Author: Philipp Fent <fent@xxxxxxxxx> Date: Mon Jun 15 13:51:09 2020 +0200 efi/libstub: Fix path separator regression [ Upstream commit 7a88a6227dc7f2e723bba11ece05e57bd8dce8e4 ] Commit 9302c1bb8e47 ("efi/libstub: Rewrite file I/O routine") introduced a regression that made a couple of (badly configured) systems fail to boot [1]: Until 5.6, we silently accepted Unix-style file separators in EFI paths, which might violate the EFI standard, but are an easy to make mistake. This fix restores the pre-5.7 behaviour. [1] https://bbs.archlinux.org/viewtopic.php?id=256273 Fixes: 9302c1bb8e47 ("efi/libstub: Rewrite file I/O routine") Signed-off-by: Philipp Fent <fent@xxxxxxxxx> Link: https://lore.kernel.org/r/20200615115109.7823-1-fent@xxxxxxxxx [ardb: rewrite as chained if/else statements] Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/firmware/efi/libstub/file.c b/drivers/firmware/efi/libstub/file.c index ea66b1f16a79d..f1c4faf58c764 100644 --- a/drivers/firmware/efi/libstub/file.c +++ b/drivers/firmware/efi/libstub/file.c @@ -104,12 +104,20 @@ static int find_file_option(const efi_char16_t *cmdline, int cmdline_len, if (!found) return 0; + /* Skip any leading slashes */ + while (cmdline[i] == L'/' || cmdline[i] == L'\\') + i++; + while (--result_len > 0 && i < cmdline_len) { - if (cmdline[i] == L'\0' || - cmdline[i] == L'\n' || - cmdline[i] == L' ') + efi_char16_t c = cmdline[i++]; + + if (c == L'\0' || c == L'\n' || c == L' ') break; - *result++ = cmdline[i++]; + else if (c == L'/') + /* Replace UNIX dir separators with EFI standard ones */ + *result++ = L'\\'; + else + *result++ = c; } *result = L'\0'; return i;