Bug 460421 - kernel: ext2 does not force ro-mode when revision level is too high [rhel-5.3]
kernel: ext2 does not force ro-mode when revision level is too high [rhel-5.3]
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
medium Severity low
: rc
: ---
Assigned To: Eric Sandeen
Red Hat Kernel QE team
Depends On:
Blocks: 460422
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Reported: 2008-08-28 03:26 EDT by Eugene Teo (Security Response)
Modified: 2010-04-01 15:57 EDT (History)
5 users (show)

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Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Last Closed: 2010-04-01 15:57:15 EDT
Type: ---
Regression: ---
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oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Eugene Teo (Security Response) 2008-08-28 03:26:41 EDT
Description of problem:
The ext2 filesystem does not force read-only mode when the revision level is too high. That is, when le32_to_cpu(es->s_rev_level) > EXT3_MAX_SUPP_REV.
Comment 2 Eugene Teo (Security Response) 2008-08-28 03:31:59 EDT
 738 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 739 {
1066     ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1067     return 0;

 576 static int ext2_setup_super (struct super_block * sb,
 577                   struct ext2_super_block * es,
 578                   int read_only)
 579 {
 580     int res = 0;
 581     struct ext2_sb_info *sbi = EXT2_SB(sb);
 583     if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 584         printk ("EXT2-fs warning: revision level too high, "
 585             "forcing read-only mode\n");
 586         res = MS_RDONLY;
 587     }
 618     return res;
 619 }

It doesn't look like this piece of code is tested at all. The status returned from ext2_setup_super is not checked at all, so what it did was to print a warning message. I believe this should be done in the early part of ext2_fill_super().
Comment 10 RHEL Product and Program Management 2009-02-16 10:34:22 EST
Updating PM score.
Comment 12 Eric Sandeen 2010-04-01 15:57:15 EDT
I don't think this is a critical fix for RHEL at this point.

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