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authorMasami Hiramatsu <mhiramat@kernel.org>2020-11-13 02:27:31 +0900
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-11-12 20:36:52 -0500
commit50b8a742850fce7293bed45753152c425f7e931b (patch)
tree2e1a2a5174f4db385f491e143be0f6800a3c65c7 /init/main.c
parent645f224e7ba2f4200bf163153d384ceb0de5462e (diff)
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bootconfig: Extend the magic check range to the preceding 3 bytes
Since Grub may align the size of initrd to 4 if user pass initrd from cpio, we have to check the preceding 3 bytes as well. Link: https://lkml.kernel.org/r/160520205132.303174.4876760192433315429.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 85c46b78da58 ("bootconfig: Add bootconfig magic word for indicating bootconfig explicitly") Reported-by: Chen Yu <yu.chen.surf@gmail.com> Tested-by: Chen Yu <yu.chen.surf@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'init/main.c')
-rw-r--r--init/main.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/init/main.c b/init/main.c
index 130376ec10ba..20baced721ad 100644
--- a/init/main.c
+++ b/init/main.c
@@ -269,14 +269,24 @@ static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
u32 size, csum;
char *data;
u32 *hdr;
+ int i;
if (!initrd_end)
return NULL;
data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
- if (memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
- return NULL;
+ /*
+ * Since Grub may align the size of initrd to 4, we must
+ * check the preceding 3 bytes as well.
+ */
+ for (i = 0; i < 4; i++) {
+ if (!memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
+ goto found;
+ data--;
+ }
+ return NULL;
+found:
hdr = (u32 *)(data - 8);
size = hdr[0];
csum = hdr[1];