Commit 0bcaa65a authored by Lubomir Rintel's avatar Lubomir Rintel Committed by Linus Torvalds
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fs/sysv: v7: adjust sanity checks for some volumes 



Newly mkfs-ed filesystems from Seventh Edition have last modification time
set to zero, but are otherwise perfectly valid.

Also, tighten up other sanity checks to filter out most filesystems with

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarLubomir Rintel <lkundrak@v3.sk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a36517e9

fs/sysv/super.c

+4 −2
Original line number Diff line number Diff line
@@ -469,7 +469,7 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent) 
	v7sb = (struct v7_super_block *) bh->b_data;

	if (fs16_to_cpu(sbi, v7sb->s_nfree) > V7_NICFREE ||

	    fs16_to_cpu(sbi, v7sb->s_ninode) > V7_NICINOD ||

	    fs32_to_cpu(sbi, v7sb->s_time) == 0)

	    fs32_to_cpu(sbi, v7sb->s_fsize) > V7_MAXSIZE)

		goto failed;



	/* plausibility check on root inode: it is a directory,
@@ -479,7 +479,9 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent) 
	v7i = (struct sysv_inode *)(bh2->b_data + 64);

	if ((fs16_to_cpu(sbi, v7i->i_mode) & ~0777) != S_IFDIR ||

	    (fs32_to_cpu(sbi, v7i->i_size) == 0) ||

	    (fs32_to_cpu(sbi, v7i->i_size) & 017) != 0)

	    (fs32_to_cpu(sbi, v7i->i_size) & 017) ||

	    (fs32_to_cpu(sbi, v7i->i_size) > V7_NFILES *

	     sizeof(struct sysv_dir_entry)))

		goto failed;

	brelse(bh2);

	bh2 = NULL;

include/linux/sysv_fs.h

+11 −0
Original line number Diff line number Diff line
@@ -148,6 +148,17 @@ struct v7_super_block { 
	char    s_fname[6];     /* file system name */

	char    s_fpack[6];     /* file system pack name */

};

/* Constants to aid sanity checking */

/* This is not a hard limit, nor enforced by v7 kernel. It's actually just

 * the limit used by Seventh Edition's ls, though is high enough to assume

 * that no reasonable file system would have that much entries in root

 * directory. Thus, if we see anything higher, we just probably got the

 * endiannes wrong. */

#define V7_NFILES	1024

/* The disk addresses are three-byte (despite direct block addresses being

 * aligned word-wise in inode). If the most significant byte is non-zero,

 * something is most likely wrong (not a filesystem, bad bytesex). */

#define V7_MAXSIZE	0x00ffffff



/* Coherent super-block data on disk */

#define COH_NICINOD	100	/* number of inode cache entries */

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