Bug 250419 - HAL fstab-sync zero-bytes /etc/fstab if / is full.
HAL fstab-sync zero-bytes /etc/fstab if / is full.
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: hal (Show other bugs)
All Linux
high Severity high
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Assigned To: David Zeuthen
Depends On:
Blocks: 246627
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Reported: 2007-08-01 10:18 EDT by Jose Plans
Modified: 2013-03-05 22:51 EST (History)
2 users (show)

See Also:
Fixed In Version: RHBA-2008-0734
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2008-07-24 15:58:52 EDT
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)
Patch from lmacchia@redhat.com (384 bytes, patch)
2007-08-01 10:26 EDT, Jose Plans
no flags Details | Diff

  None (edit)
Description Jose Plans 2007-08-01 10:18:02 EDT
Description of problem:
fstab-sync from hal doesn't detect properly write(2) as the error "-1" is stored
on a signed size_t instead of ssize_t.

This has made some systems to lose their /etc/fstab and therfore provide some
serious impacts on boot.

static boolean
add_udi (const char *udi)
        if (!fs_table_write (fs_table, fd)) <-- fs_table_write will always
return 1 [1]
                goto error;
        if (rename (temp_filename, _PATH_FSTAB) < 0) <- rename will report
ENOSPC but.. it was too late.

[1] return will always be TRUE as size_t is unsigned:

static boolean
fs_table_write (FSTable *table, int fd)
  char *fstab_contents;
-  size_t bytes_written, bytes_to_write;
+  size_t bytes_written, bytes_to_write; <--- signed for error handling on write(2)
  while ((bytes_written = write (fd, fstab_contents + bytes_written,
                                 bytes_to_write)) < bytes_to_write)
      if (bytes_written < 0)             <--- with size_t this will never happen.
  return TRUE; <--- return 1.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
- fill the root partition to 100%
- crash
- system starts
- it mounts all the file system according to fstab
- it runs fstab-sync and NOW corrupts it (as per strace)
Actual results:
/etc/fstab empty.

Expected results:
/etc/fstab not empty.

Additional info:
Patch attached from Leo Macchia <lmacchia@redhat.com>
Comment 1 Jose Plans 2007-08-01 10:26:48 EDT
Created attachment 160416 [details]
Patch from lmacchia@redhat.com
Comment 2 Jose Plans 2007-08-01 10:28:40 EDT
Patched confirmed to work.
Comment 3 Jose Plans 2007-08-01 10:30:26 EDT
Hmm typo on #c0 :
-  size_t bytes_written, bytes_to_write;
+  ssize_t bytes_written, bytes_to_write; <--- signed for error handling on write(2)
Comment 4 RHEL Product and Program Management 2007-11-28 23:16:43 EST
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
Comment 5 David Zeuthen 2008-02-15 16:16:52 EST
Looks like something we should fix. Dev ACK.
Comment 7 David Zeuthen 2008-04-10 18:18:29 EDT
Fix is in hal-0.4.2-8.EL4.
Comment 11 errata-xmlrpc 2008-07-24 15:58:52 EDT
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.


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