[Bug libc/17273] New: getmntent() returns wrong default value for fs_passno

[Bug libc/17273] New: getmntent() returns wrong default value for fs_passno

[naszar at ya dot ru]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

            Bug ID: 17273
           Summary: getmntent() returns wrong default value for fs_passno
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: libc
          Assignee: unassigned at sourceware dot org
          Reporter: naszar at ya dot ru
                CC: drepper.fsp at gmail dot com

Created attachment 7747
  --> https://sourceware.org/bugzilla/attachment.cgi?id=7747&action=edit
simple test program

man 5 fstab states that if the fifth field (fs_freq) and the sixth field
(fs_passno) is not present a value of zero is returned (i.q.
fs_req=0,fs_passno=0 if there is no fifth and sixth field in /etc/fstab  line).
If fourth field ends with '\n' all work fine. But if there is extra tabs or
spaces getmntent() returns garbage in ((struct mntent *) mp)->mnt_passno. It is
because in misc/mntent_r.c:__getmntent_r() at line 167 no checks that sscanf()
returns EOF or no striping for spaces and tabs like it done at line 164 for
example.
In my mashine attached test_mntent (for testtab which also attached) say:
mnt_dir=/home    mnt_freq=42    mnt_passno=666
mnt_dir=/home    mnt_freq=42    mnt_passno=666
but must:
mnt_dir=/home    mnt_freq=42    mnt_passno=666
mnt_dir=/home    mnt_freq=0    mnt_passno=0

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[naszar at ya dot ru]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

--- Comment #1 from naszar <naszar at ya dot ru> ---
Created attachment 7748
  --> https://sourceware.org/bugzilla/attachment.cgi?id=7748&action=edit
test fstab

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[naszar at ya dot ru]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

naszar <naszar at ya dot ru> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |naszar at ya dot ru

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
            Version|unspecified                 |2.21
         Resolution|---                         |FIXED

--- Comment #2 from Mike Frysinger <vapier at gentoo dot org> ---
this was discussed here:
https://sourceware.org/ml/libc-alpha/2014-08/msg00476.html
https://sourceware.org/ml/libc-alpha/2014-10/msg00035.html
https://sourceware.org/ml/libc-alpha/2014-12/msg00225.html
https://sourceware.org/ml/libc-alpha/2015-01/msg00109.html

and merged here:
https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=fb87ee96d7dd0714d52004e4676629f8d9db732f

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |18887


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=18887
[Bug 18887] memory corruption when using getmntent on blank lines
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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

--- Comment #3 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
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The branch, master has been updated
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commit b0e805fa0d6fea33745952df7b7f5442ca4c374f
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Fri Aug 28 17:08:49 2015 -0400

    getmntent: fix memory corruption w/blank lines [BZ #18887]

    The fix for BZ #17273 introduced a single byte of memory corruption when
    the line is entirely blank.  It would walk back past the start of the
    buffer if the heap happened to be 0x20 or 0x09 and then write a NUL byte.
        buffer = '\n';
        end_ptr = buffer;
        while (end_ptr[-1] == ' ' || end_ptr[-1] == '\t')
                end_ptr--;
        *end_ptr = '\0';

    Fix that and rework the tests.  Adding the testcase for BZ #17273 to the
    existing \040 parser does not really make sense as it's unrelated, and
    leads to confusing behavior: it implicitly relies on the new entry being
    longer than the previous entry (since it just rewinds the FILE*).  Split
    it out into its own dedicated testcase instead.

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                          |   10 +++++
 misc/Makefile                                      |    3 +-
 misc/mntent_r.c                                    |    4 +-
 .../tst-mntent-blank-corrupt.c                     |   43 ++++++++-----------
 .../tst-mntent-blank-passno.c                      |   40 ++++++++++--------
 misc/tst-mntent.c                                  |   20 ---------
 6 files changed, 55 insertions(+), 65 deletions(-)
 copy posix/bug-regex35.c => misc/tst-mntent-blank-corrupt.c (60%)
 copy math/tst-definitions.c => misc/tst-mntent-blank-passno.c (55%)

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

--- Comment #4 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
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The branch, release/2.21/master has been updated
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      from  978908245b2c0f759100708a9966649f7b273664 (commit)

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commit f2cdbadd8a078482d3b9fc2b59e888c64cc4efae
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Fri Aug 28 17:08:49 2015 -0400

    getmntent: fix memory corruption w/blank lines [BZ #18887]

    The fix for BZ #17273 introduced a single byte of memory corruption when
    the line is entirely blank.  It would walk back past the start of the
    buffer if the heap happened to be 0x20 or 0x09 and then write a NUL byte.
        buffer = '\n';
        end_ptr = buffer;
        while (end_ptr[-1] == ' ' || end_ptr[-1] == '\t')
                end_ptr--;
        *end_ptr = '\0';

    Fix that and rework the tests.  Adding the testcase for BZ #17273 to the
    existing \040 parser does not really make sense as it's unrelated, and
    leads to confusing behavior: it implicitly relies on the new entry being
    longer than the previous entry (since it just rewinds the FILE*).  Split
    it out into its own dedicated testcase instead.

    (cherry picked from commit b0e805fa0d6fea33745952df7b7f5442ca4c374f)

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                          |   10 +++++
 NEWS                                               |    2 +-
 misc/Makefile                                      |    3 +-
 misc/mntent_r.c                                    |    4 +-
 .../tst-mntent-blank-corrupt.c                     |   27 +++++++------
 .../tst-mntent-blank-passno.c                      |   40 +++++++++++---------
 misc/tst-mntent.c                                  |   20 ----------
 7 files changed, 53 insertions(+), 53 deletions(-)
 copy libio/test-fmemopen.c => misc/tst-mntent-blank-corrupt.c (60%)
 copy math/tst-definitions.c => misc/tst-mntent-blank-passno.c (55%)

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

--- Comment #5 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
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The branch, release/2.22/master has been updated
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      from  64c25345714d792b283c8c8469d58f898d1ef109 (commit)

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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=3007f797a1a596e954f44879a5a7267966186ba4

commit 3007f797a1a596e954f44879a5a7267966186ba4
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Fri Aug 28 17:08:49 2015 -0400

    getmntent: fix memory corruption w/blank lines [BZ #18887]

    The fix for BZ #17273 introduced a single byte of memory corruption when
    the line is entirely blank.  It would walk back past the start of the
    buffer if the heap happened to be 0x20 or 0x09 and then write a NUL byte.
        buffer = '\n';
        end_ptr = buffer;
        while (end_ptr[-1] == ' ' || end_ptr[-1] == '\t')
                end_ptr--;
        *end_ptr = '\0';

    Fix that and rework the tests.  Adding the testcase for BZ #17273 to the
    existing \040 parser does not really make sense as it's unrelated, and
    leads to confusing behavior: it implicitly relies on the new entry being
    longer than the previous entry (since it just rewinds the FILE*).  Split
    it out into its own dedicated testcase instead.

    (cherry picked from commit b0e805fa0d6fea33745952df7b7f5442ca4c374f)

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                          |   10 +++++
 NEWS                                               |    2 +-
 misc/Makefile                                      |    3 +-
 misc/mntent_r.c                                    |    4 +-
 .../tst-mntent-blank-corrupt.c                     |   43 ++++++++-----------
 .../tst-mntent-blank-passno.c                      |   40 ++++++++++--------
 misc/tst-mntent.c                                  |   20 ---------
 7 files changed, 56 insertions(+), 66 deletions(-)
 copy posix/bug-regex35.c => misc/tst-mntent-blank-corrupt.c (60%)
 copy math/tst-definitions.c => misc/tst-mntent-blank-passno.c (55%)

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

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https://sourceware.org/bugzilla/show_bug.cgi?id=17273

--- Comment #6 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
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The branch, gentoo/2.21 has been updated
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      from  43d7ce9238c59c61003994cb26eff4a6a072ebd5 (commit)

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commit 460e5da421067eb690ba3b9d11183c4b7db37e4f
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Fri Aug 28 17:08:49 2015 -0400

    getmntent: fix memory corruption w/blank lines [BZ #18887]

    The fix for BZ #17273 introduced a single byte of memory corruption when
    the line is entirely blank.  It would walk back past the start of the
    buffer if the heap happened to be 0x20 or 0x09 and then write a NUL byte.
        buffer = '\n';
        end_ptr = buffer;
        while (end_ptr[-1] == ' ' || end_ptr[-1] == '\t')
                end_ptr--;
        *end_ptr = '\0';

    Fix that and rework the tests.  Adding the testcase for BZ #17273 to the
    existing \040 parser does not really make sense as it's unrelated, and
    leads to confusing behavior: it implicitly relies on the new entry being
    longer than the previous entry (since it just rewinds the FILE*).  Split
    it out into its own dedicated testcase instead.

    (cherry picked from commit b0e805fa0d6fea33745952df7b7f5442ca4c374f)
    (cherry picked from commit f2cdbadd8a078482d3b9fc2b59e888c64cc4efae)

-----------------------------------------------------------------------

Summary of changes:
 misc/Makefile                                      |    3 +-
 misc/mntent_r.c                                    |    4 +-
 .../tst-mntent-blank-corrupt.c                     |   27 +++++++------
 .../tst-mntent-blank-passno.c                      |   40 +++++++++++---------
 misc/tst-mntent.c                                  |   20 ----------
 5 files changed, 42 insertions(+), 52 deletions(-)
 copy libio/test-fmemopen.c => misc/tst-mntent-blank-corrupt.c (60%)
 copy math/tst-definitions.c => misc/tst-mntent-blank-passno.c (55%)

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[Bug libc/17273] getmntent() returns wrong default value for fs_passno

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=17273

--- Comment #7 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
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The branch, gentoo/2.22 has been updated
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commit ca6a9ce6151759981cc2efd58e053148c7db2fea
Author: Mike Frysinger <vapier@gentoo.org>
Date:   Fri Aug 28 17:08:49 2015 -0400

    getmntent: fix memory corruption w/blank lines [BZ #18887]

    The fix for BZ #17273 introduced a single byte of memory corruption when
    the line is entirely blank.  It would walk back past the start of the
    buffer if the heap happened to be 0x20 or 0x09 and then write a NUL byte.
        buffer = '\n';
        end_ptr = buffer;
        while (end_ptr[-1] == ' ' || end_ptr[-1] == '\t')
                end_ptr--;
        *end_ptr = '\0';

    Fix that and rework the tests.  Adding the testcase for BZ #17273 to the
    existing \040 parser does not really make sense as it's unrelated, and
    leads to confusing behavior: it implicitly relies on the new entry being
    longer than the previous entry (since it just rewinds the FILE*).  Split
    it out into its own dedicated testcase instead.

    (cherry picked from commit b0e805fa0d6fea33745952df7b7f5442ca4c374f)
    (cherry picked from commit 3007f797a1a596e954f44879a5a7267966186ba4)

-----------------------------------------------------------------------

Summary of changes:
 misc/Makefile                                      |    3 +-
 misc/mntent_r.c                                    |    4 +-
 .../tst-mntent-blank-corrupt.c                     |   43 ++++++++-----------
 .../tst-mntent-blank-passno.c                      |   40 ++++++++++--------
 misc/tst-mntent.c                                  |   20 ---------
 5 files changed, 45 insertions(+), 65 deletions(-)
 copy posix/bug-regex35.c => misc/tst-mntent-blank-corrupt.c (60%)
 copy math/tst-definitions.c => misc/tst-mntent-blank-passno.c (55%)

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