| From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 044/164] ext4: fix potential use after free in __ext4_journal_stop | Date | Wed, 2 Dec 2015 08:58:15 -0800 |
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3.19.8-ckt11 -stable review patch. If anyone has any objections, please let me know.
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From: Lukas Czerner <lczerner@redhat.com>
commit 6934da9238da947628be83635e365df41064b09b upstream.
There is a use-after-free possibility in __ext4_journal_stop() in the case that we free the handle in the first jbd2_journal_stop() because we're referencing handle->h_err afterwards. This was introduced in 9705acd63b125dee8b15c705216d7186daea4625 and it is wrong. Fix it by storing the handle->h_err value beforehand and avoid referencing potentially freed handle.
Fixes: 9705acd63b125dee8b15c705216d7186daea4625 Signed-off-by: Lukas Czerner <lczerner@redhat.com> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- fs/ext4/ext4_jbd2.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index d418431..e770c1ee 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -88,13 +88,13 @@ int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle) return 0; } + err = handle->h_err; if (!handle->h_transaction) { - err = jbd2_journal_stop(handle); - return handle->h_err ? handle->h_err : err; + rc = jbd2_journal_stop(handle); + return err ? err : rc; } sb = handle->h_transaction->t_journal->j_private; - err = handle->h_err; rc = jbd2_journal_stop(handle); if (!err) -- 1.9.1
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