From e246eb568bc4cbbdd8a30a3c11151ff9b7ca7312 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Mon, 15 Feb 2016 10:34:05 +0000 Subject: [PATCH 1/2] efi: Add pstore variables to the deletion whitelist Laszlo explains why this is a good idea, 'This is because the pstore filesystem can be backed by UEFI variables, and (for example) a crash might dump the last kilobytes of the dmesg into a number of pstore entries, each entry backed by a separate UEFI variable in the above GUID namespace, and with a variable name according to the above pattern. Please see "drivers/firmware/efi/efi-pstore.c". While this patch series will not prevent the user from deleting those UEFI variables via the pstore filesystem (i.e., deleting a pstore fs entry will continue to delete the backing UEFI variable), I think it would be nice to preserve the possibility for the sysadmin to delete Linux-created UEFI variables that carry portions of the crash log, *without* having to mount the pstore filesystem.' There's also no chance of causing machines to become bricked by deleting these variables, which is the whole purpose of excluding things from the whitelist. Use the LINUX_EFI_CRASH_GUID guid and a wildcard '*' for the match so that we don't have to update the string in the future if new variable name formats are created for crash dump variables. Reported-by: Laszlo Ersek Acked-by: Peter Jones Tested-by: Peter Jones Cc: Matthew Garrett Cc: "Lee, Chun-Yi" Signed-off-by: Matt Fleming --- drivers/firmware/efi/vars.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index 50f10bad2604..7f2ea21c730d 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -198,6 +198,7 @@ static const struct variable_validate variable_validate[] = { { EFI_GLOBAL_VARIABLE_GUID, "OsIndications", NULL }, { EFI_GLOBAL_VARIABLE_GUID, "PlatformLang", validate_ascii_string }, { EFI_GLOBAL_VARIABLE_GUID, "Timeout", validate_uint16 }, + { LINUX_EFI_CRASH_GUID, "*", NULL }, { NULL_GUID, "", NULL }, }; From a68075908a37850918ad96b056acc9ac4ce1bd90 Mon Sep 17 00:00:00 2001 From: Jason Andryuk Date: Fri, 12 Feb 2016 23:13:33 +0000 Subject: [PATCH 2/2] lib/ucs2_string: Correct ucs2 -> utf8 conversion The comparisons should be >= since 0x800 and 0x80 require an additional bit to store. For the 3 byte case, the existing shift would drop off 2 more bits than intended. For the 2 byte case, there should be 5 bits bits in byte 1, and 6 bits in byte 2. Signed-off-by: Jason Andryuk Reviewed-by: Laszlo Ersek Cc: Peter Jones Cc: Matthew Garrett Cc: "Lee, Chun-Yi" Signed-off-by: Matt Fleming --- lib/ucs2_string.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c index 17dd74e21ef9..f0b323abb4c6 100644 --- a/lib/ucs2_string.c +++ b/lib/ucs2_string.c @@ -59,9 +59,9 @@ ucs2_utf8size(const ucs2_char_t *src) for (i = 0; i < ucs2_strlen(src); i++) { u16 c = src[i]; - if (c > 0x800) + if (c >= 0x800) j += 3; - else if (c > 0x80) + else if (c >= 0x80) j += 2; else j += 1; @@ -88,19 +88,19 @@ ucs2_as_utf8(u8 *dest, const ucs2_char_t *src, unsigned long maxlength) for (i = 0; maxlength && i < limit; i++) { u16 c = src[i]; - if (c > 0x800) { + if (c >= 0x800) { if (maxlength < 3) break; maxlength -= 3; dest[j++] = 0xe0 | (c & 0xf000) >> 12; - dest[j++] = 0x80 | (c & 0x0fc0) >> 8; + dest[j++] = 0x80 | (c & 0x0fc0) >> 6; dest[j++] = 0x80 | (c & 0x003f); - } else if (c > 0x80) { + } else if (c >= 0x80) { if (maxlength < 2) break; maxlength -= 2; - dest[j++] = 0xc0 | (c & 0xfe0) >> 5; - dest[j++] = 0x80 | (c & 0x01f); + dest[j++] = 0xc0 | (c & 0x7c0) >> 6; + dest[j++] = 0x80 | (c & 0x03f); } else { maxlength -= 1; dest[j++] = c & 0x7f;