cramfs: error message about endianess (ac8d35c5) · Commits · 戴 / test

The README file in the cramfs subdirectory says: "All data is currently in host-endian format; neither mkcramfs nor the kernel ever do swabbing." If somebody tries to mount a cramfs with the wrong endianess, cramfs only complains about a wrong magic but doesn't inform the user that only the endianess isn't right. The following patch adds an error message to the cramfs sources. If a user tries to mount a cramfs with the wrong endianess using the patched sources, cramfs will display the message "cramfs: wrong endianess". Signed-off-by:

Andi Drebes <lists-receive@programmierforen.de> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

fs/cramfs/inode.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -258,12 +258,21 @@ static int cramfs_fill_super(struct super_block sb, void data, int silent)

		/* Do sanity checks on the superblock */
		if (super.magic != CRAMFS_MAGIC) {
		/* check for wrong endianess */
		if (super.magic == CRAMFS_MAGIC_WEND) {
		if (!silent)
		printk(KERN_ERR "cramfs: wrong endianess\n");
		goto out;
		}

		/* check at 512 byte offset */
		mutex_lock(&read_mutex);
		memcpy(&super, cramfs_read(sb, 512, sizeof(super)), sizeof(super));
		mutex_unlock(&read_mutex);
		if (super.magic != CRAMFS_MAGIC) {
		if (!silent)
		if (super.magic == CRAMFS_MAGIC_WEND && !silent)
		printk(KERN_ERR "cramfs: wrong endianess\n");
		else if (!silent)
		printk(KERN_ERR "cramfs: wrong magic\n");
		goto out;
		}

include/linux/cramfs_fs.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@
		#include <linux/types.h>

		#define CRAMFS_MAGIC 0x28cd3d45 /* some random number */
		#define CRAMFS_MAGIC_WEND 0x453dcd28 /* magic number with the wrong endianess */
		#define CRAMFS_SIGNATURE "Compressed ROMFS"

		/*

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