[PATCH AUTOSEL 5.6 018/606] bootconfig: Fix to remove bootconfig data from initrd while boot

Sasha Levin
2020-06-09T00:42:14Z

From: Masami Hiramatsu <mhiramat@kernel.org>

commit de462e5f10718517bacf2f84c8aa2804567ef7df upstream.

If there is a bootconfig data in the tail of initrd/initramfs,
initrd image sanity check caused an error while decompression
stage as follows.

[ 0.883882] Unpacking initramfs...
[ 2.696429] Initramfs unpacking failed: invalid magic at start of compressed archive

This error will be ignored if CONFIG_BLK_DEV_RAM=n,
but CONFIG_BLK_DEV_RAM=y the kernel failed to mount rootfs
and causes a panic.

To fix this issue, shrink down the initrd_end for removing
tailing bootconfig data while boot the kernel.

Link: http://lkml.kernel.org/r/158788401014.24243.17424755854115077915.stgit@devnote2

Cc: Borislav Petkov <bp@alien8.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 7684b8582c24 ("bootconfig: Load boot config from the tail of initrd")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
init/main.c | 69 ++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 52 insertions(+), 17 deletions(-)

diff --git a/init/main.c b/init/main.c
index 9c7948b3763a..ee0345e7e9f1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -257,6 +257,47 @@ static int __init loglevel(char *str)

early_param("loglevel", loglevel);

+#ifdef CONFIG_BLK_DEV_INITRD
+static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
+{
+ u32 size, csum;
+ char *data;
+ u32 *hdr;
+
+ if (!initrd_end)
+ return NULL;
+
+ data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
+ if (memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
+ return NULL;
+
+ hdr = (u32 *)(data - 8);
+ size = hdr[0];
+ csum = hdr[1];
+
+ data = ((void *)hdr) - size;
+ if ((unsigned long)data < initrd_start) {
+ pr_err("bootconfig size %d is greater than initrd size %ld\n",
+ size, initrd_end - initrd_start);
+ return NULL;
+ }
+
+ /* Remove bootconfig from initramfs/initrd */
+ initrd_end = (unsigned long)data;
+ if (_size)
+ *_size = size;
+ if (_csum)
+ *_csum = csum;
+
+ return data;
+}
+#else
+static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
+{
+ return NULL;
+}
+#endif
+
#ifdef CONFIG_BOOT_CONFIG

char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
@@ -355,9 +396,12 @@ static void __init setup_boot_config(const char *cmdline)
static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
u32 size, csum;
char *data, *copy;
- u32 *hdr;
int ret;

+ data = get_boot_config_from_initrd(&size, &csum);
+ if (!data)
+ goto not_found;
+
strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
bootconfig_params);
@@ -365,27 +409,12 @@ static void __init setup_boot_config(const char *cmdline)
if (!bootconfig_found)
return;

- if (!initrd_end)
- goto not_found;
-
- data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
- if (memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
- goto not_found;
-
- hdr = (u32 *)(data - 8);
- size = hdr[0];
- csum = hdr[1];
-
if (size >= XBC_DATA_MAX) {
pr_err("bootconfig size %d greater than max size %d\n",
size, XBC_DATA_MAX);
return;
}

- data = ((void *)hdr) - size;
- if ((unsigned long)data < initrd_start)
- goto not_found;
-
if (boot_config_checksum((unsigned char *)data, size) != csum) {
pr_err("bootconfig checksum failed\n");
return;
@@ -414,8 +443,14 @@ static void __init setup_boot_config(const char *cmdline)
not_found:
pr_err("'bootconfig' found on command line, but no bootconfig found\n");
}
+
#else
-#define setup_boot_config(cmdline) do { } while (0)
+
+static void __init setup_boot_config(const char *cmdline)
+{
+ /* Remove bootconfig data from initrd */
+ get_boot_config_from_initrd(NULL, NULL);
+}

static int __init warn_bootconfig(char *str)
{
--
2.25.1