efi/x86: Map the entire EFI vendor string before copying it
BugLink: https://bugs.launchpad.net/bugs/1868627 [ Upstream commit ffc2760b ] Fix a couple of issues with the way we map and copy the vendor string: - we map only 2 bytes, which usually works since you get at least a page, but if the vendor string happens to cross a page boundary, a crash will result - only call early_memunmap() if early_memremap() succeeded, or we will call it with a NULL address which it doesn't like, - while at it, switch to early_memremap_ro(), and array indexing rather than pointer dereferencing to read the CHAR16 characters. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arvind Sankar <nivedita@alum.mit.edu> Cc: Matthew Garrett <mjg59@google.com> Cc: linux-efi@vger.kernel.org Fixes: 5b83683f ("x86: EFI runtime service support") Link: https://lkml.kernel.org/r/20200103113953.9571-5-ardb@kernel.orgSigned-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com> Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>
Showing
Please register or sign in to comment